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linux-pinenote/security/smack/smack_lsm.c
Al Viro 4040153087 security: trim security.h 
Trim security.h

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: James Morris <jmorris@namei.org>
2012-02-14 10:45:42 +11:00

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/*
* Simplified MAC Kernel (smack) security module
*
* This file contains the smack hook function implementations.
*
* Authors:
* Casey Schaufler <casey@schaufler-ca.com>
* Jarkko Sakkinen <jarkko.sakkinen@intel.com>
*
* Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
* Copyright (C) 2009 Hewlett-Packard Development Company, L.P.
* Paul Moore <paul@paul-moore.com>
* Copyright (C) 2010 Nokia Corporation
* Copyright (C) 2011 Intel Corporation.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2,
* as published by the Free Software Foundation.
*/
#include <linux/xattr.h>
#include <linux/pagemap.h>
#include <linux/mount.h>
#include <linux/stat.h>
#include <linux/kd.h>
#include <asm/ioctls.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/pipe_fs_i.h>
#include <net/netlabel.h>
#include <net/cipso_ipv4.h>
#include <linux/audit.h>
#include <linux/magic.h>
#include <linux/dcache.h>
#include <linux/personality.h>
#include <linux/msg.h>
#include <linux/shm.h>
#include <linux/binfmts.h>
#include "smack.h"
#define task_security(task) (task_cred_xxx((task), security))
#define TRANS_TRUE "TRUE"
#define TRANS_TRUE_SIZE 4
/**
* smk_fetch - Fetch the smack label from a file.
* @ip: a pointer to the inode
* @dp: a pointer to the dentry
*
* Returns a pointer to the master list entry for the Smack label
* or NULL if there was no label to fetch.
*/
static char *smk_fetch(const char *name, struct inode *ip, struct dentry *dp)
{
int rc;
char in[SMK_LABELLEN];
if (ip->i_op->getxattr == NULL)
return NULL;
rc = ip->i_op->getxattr(dp, name, in, SMK_LABELLEN);
if (rc < 0)
return NULL;
return smk_import(in, rc);
}
/**
* new_inode_smack - allocate an inode security blob
* @smack: a pointer to the Smack label to use in the blob
*
* Returns the new blob or NULL if there's no memory available
*/
struct inode_smack *new_inode_smack(char *smack)
{
struct inode_smack *isp;
isp = kzalloc(sizeof(struct inode_smack), GFP_KERNEL);
if (isp == NULL)
return NULL;
isp->smk_inode = smack;
isp->smk_flags = 0;
mutex_init(&isp->smk_lock);
return isp;
}
/**
* new_task_smack - allocate a task security blob
* @smack: a pointer to the Smack label to use in the blob
*
* Returns the new blob or NULL if there's no memory available
*/
static struct task_smack *new_task_smack(char *task, char *forked, gfp_t gfp)
{
struct task_smack *tsp;
tsp = kzalloc(sizeof(struct task_smack), gfp);
if (tsp == NULL)
return NULL;
tsp->smk_task = task;
tsp->smk_forked = forked;
INIT_LIST_HEAD(&tsp->smk_rules);
mutex_init(&tsp->smk_rules_lock);
return tsp;
}
/**
* smk_copy_rules - copy a rule set
* @nhead - new rules header pointer
* @ohead - old rules header pointer
*
* Returns 0 on success, -ENOMEM on error
*/
static int smk_copy_rules(struct list_head *nhead, struct list_head *ohead,
gfp_t gfp)
{
struct smack_rule *nrp;
struct smack_rule *orp;
int rc = 0;
INIT_LIST_HEAD(nhead);
list_for_each_entry_rcu(orp, ohead, list) {
nrp = kzalloc(sizeof(struct smack_rule), gfp);
if (nrp == NULL) {
rc = -ENOMEM;
break;
}
*nrp = *orp;
list_add_rcu(&nrp->list, nhead);
}
return rc;
}
/*
* LSM hooks.
* We he, that is fun!
*/
/**
* smack_ptrace_access_check - Smack approval on PTRACE_ATTACH
* @ctp: child task pointer
* @mode: ptrace attachment mode
*
* Returns 0 if access is OK, an error code otherwise
*
* Do the capability checks, and require read and write.
*/
static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode)
{
int rc;
struct smk_audit_info ad;
char *tsp;
rc = cap_ptrace_access_check(ctp, mode);
if (rc != 0)
return rc;
tsp = smk_of_task(task_security(ctp));
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
smk_ad_setfield_u_tsk(&ad, ctp);
rc = smk_curacc(tsp, MAY_READWRITE, &ad);
return rc;
}
/**
* smack_ptrace_traceme - Smack approval on PTRACE_TRACEME
* @ptp: parent task pointer
*
* Returns 0 if access is OK, an error code otherwise
*
* Do the capability checks, and require read and write.
*/
static int smack_ptrace_traceme(struct task_struct *ptp)
{
int rc;
struct smk_audit_info ad;
char *tsp;
rc = cap_ptrace_traceme(ptp);
if (rc != 0)
return rc;
tsp = smk_of_task(task_security(ptp));
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
smk_ad_setfield_u_tsk(&ad, ptp);
rc = smk_curacc(tsp, MAY_READWRITE, &ad);
return rc;
}
/**
* smack_syslog - Smack approval on syslog
* @type: message type
*
* Require that the task has the floor label
*
* Returns 0 on success, error code otherwise.
*/
static int smack_syslog(int typefrom_file)
{
int rc = 0;
char *sp = smk_of_current();
if (capable(CAP_MAC_OVERRIDE))
return 0;
if (sp != smack_known_floor.smk_known)
rc = -EACCES;
return rc;
}
/*
* Superblock Hooks.
*/
/**
* smack_sb_alloc_security - allocate a superblock blob
* @sb: the superblock getting the blob
*
* Returns 0 on success or -ENOMEM on error.
*/
static int smack_sb_alloc_security(struct super_block *sb)
{
struct superblock_smack *sbsp;
sbsp = kzalloc(sizeof(struct superblock_smack), GFP_KERNEL);
if (sbsp == NULL)
return -ENOMEM;
sbsp->smk_root = smack_known_floor.smk_known;
sbsp->smk_default = smack_known_floor.smk_known;
sbsp->smk_floor = smack_known_floor.smk_known;
sbsp->smk_hat = smack_known_hat.smk_known;
sbsp->smk_initialized = 0;
spin_lock_init(&sbsp->smk_sblock);
sb->s_security = sbsp;
return 0;
}
/**
* smack_sb_free_security - free a superblock blob
* @sb: the superblock getting the blob
*
*/
static void smack_sb_free_security(struct super_block *sb)
{
kfree(sb->s_security);
sb->s_security = NULL;
}
/**
* smack_sb_copy_data - copy mount options data for processing
* @orig: where to start
* @smackopts: mount options string
*
* Returns 0 on success or -ENOMEM on error.
*
* Copy the Smack specific mount options out of the mount
* options list.
*/
static int smack_sb_copy_data(char *orig, char *smackopts)
{
char *cp, *commap, *otheropts, *dp;
otheropts = (char *)get_zeroed_page(GFP_KERNEL);
if (otheropts == NULL)
return -ENOMEM;
for (cp = orig, commap = orig; commap != NULL; cp = commap + 1) {
if (strstr(cp, SMK_FSDEFAULT) == cp)
dp = smackopts;
else if (strstr(cp, SMK_FSFLOOR) == cp)
dp = smackopts;
else if (strstr(cp, SMK_FSHAT) == cp)
dp = smackopts;
else if (strstr(cp, SMK_FSROOT) == cp)
dp = smackopts;
else
dp = otheropts;
commap = strchr(cp, ',');
if (commap != NULL)
*commap = '\0';
if (*dp != '\0')
strcat(dp, ",");
strcat(dp, cp);
}
strcpy(orig, otheropts);
free_page((unsigned long)otheropts);
return 0;
}
/**
* smack_sb_kern_mount - Smack specific mount processing
* @sb: the file system superblock
* @flags: the mount flags
* @data: the smack mount options
*
* Returns 0 on success, an error code on failure
*/
static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
{
struct dentry *root = sb->s_root;
struct inode *inode = root->d_inode;
struct superblock_smack *sp = sb->s_security;
struct inode_smack *isp;
char *op;
char *commap;
char *nsp;
spin_lock(&sp->smk_sblock);
if (sp->smk_initialized != 0) {
spin_unlock(&sp->smk_sblock);
return 0;
}
sp->smk_initialized = 1;
spin_unlock(&sp->smk_sblock);
for (op = data; op != NULL; op = commap) {
commap = strchr(op, ',');
if (commap != NULL)
*commap++ = '\0';
if (strncmp(op, SMK_FSHAT, strlen(SMK_FSHAT)) == 0) {
op += strlen(SMK_FSHAT);
nsp = smk_import(op, 0);
if (nsp != NULL)
sp->smk_hat = nsp;
} else if (strncmp(op, SMK_FSFLOOR, strlen(SMK_FSFLOOR)) == 0) {
op += strlen(SMK_FSFLOOR);
nsp = smk_import(op, 0);
if (nsp != NULL)
sp->smk_floor = nsp;
} else if (strncmp(op, SMK_FSDEFAULT,
strlen(SMK_FSDEFAULT)) == 0) {
op += strlen(SMK_FSDEFAULT);
nsp = smk_import(op, 0);
if (nsp != NULL)
sp->smk_default = nsp;
} else if (strncmp(op, SMK_FSROOT, strlen(SMK_FSROOT)) == 0) {
op += strlen(SMK_FSROOT);
nsp = smk_import(op, 0);
if (nsp != NULL)
sp->smk_root = nsp;
}
}
/*
* Initialize the root inode.
*/
isp = inode->i_security;
if (isp == NULL)
inode->i_security = new_inode_smack(sp->smk_root);
else
isp->smk_inode = sp->smk_root;
return 0;
}
/**
* smack_sb_statfs - Smack check on statfs
* @dentry: identifies the file system in question
*
* Returns 0 if current can read the floor of the filesystem,
* and error code otherwise
*/
static int smack_sb_statfs(struct dentry *dentry)
{
struct superblock_smack *sbp = dentry->d_sb->s_security;
int rc;
struct smk_audit_info ad;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
rc = smk_curacc(sbp->smk_floor, MAY_READ, &ad);
return rc;
}
/**
* smack_sb_mount - Smack check for mounting
* @dev_name: unused
* @path: mount point
* @type: unused
* @flags: unused
* @data: unused
*
* Returns 0 if current can write the floor of the filesystem
* being mounted on, an error code otherwise.
*/
static int smack_sb_mount(char *dev_name, struct path *path,
char *type, unsigned long flags, void *data)
{
struct superblock_smack *sbp = path->dentry->d_sb->s_security;
struct smk_audit_info ad;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
smk_ad_setfield_u_fs_path(&ad, *path);
return smk_curacc(sbp->smk_floor, MAY_WRITE, &ad);
}
/**
* smack_sb_umount - Smack check for unmounting
* @mnt: file system to unmount
* @flags: unused
*
* Returns 0 if current can write the floor of the filesystem
* being unmounted, an error code otherwise.
*/
static int smack_sb_umount(struct vfsmount *mnt, int flags)
{
struct superblock_smack *sbp;
struct smk_audit_info ad;
struct path path;
path.dentry = mnt->mnt_root;
path.mnt = mnt;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
smk_ad_setfield_u_fs_path(&ad, path);
sbp = path.dentry->d_sb->s_security;
return smk_curacc(sbp->smk_floor, MAY_WRITE, &ad);
}
/*
* BPRM hooks
*/
/**
* smack_bprm_set_creds - set creds for exec
* @bprm: the exec information
*
* Returns 0 if it gets a blob, -ENOMEM otherwise
*/
static int smack_bprm_set_creds(struct linux_binprm *bprm)
{
struct inode *inode = bprm->file->f_path.dentry->d_inode;
struct task_smack *bsp = bprm->cred->security;
struct inode_smack *isp;
int rc;
rc = cap_bprm_set_creds(bprm);
if (rc != 0)
return rc;
if (bprm->cred_prepared)
return 0;
isp = inode->i_security;
if (isp->smk_task == NULL || isp->smk_task == bsp->smk_task)
return 0;
if (bprm->unsafe)
return -EPERM;
bsp->smk_task = isp->smk_task;
bprm->per_clear |= PER_CLEAR_ON_SETID;
return 0;
}
/**
* smack_bprm_committing_creds - Prepare to install the new credentials
* from bprm.
*
* @bprm: binprm for exec
*/
static void smack_bprm_committing_creds(struct linux_binprm *bprm)
{
struct task_smack *bsp = bprm->cred->security;
if (bsp->smk_task != bsp->smk_forked)
current->pdeath_signal = 0;
}
/**
* smack_bprm_secureexec - Return the decision to use secureexec.
* @bprm: binprm for exec
*
* Returns 0 on success.
*/
static int smack_bprm_secureexec(struct linux_binprm *bprm)
{
struct task_smack *tsp = current_security();
int ret = cap_bprm_secureexec(bprm);
if (!ret && (tsp->smk_task != tsp->smk_forked))
ret = 1;
return ret;
}
/*
* Inode hooks
*/
/**
* smack_inode_alloc_security - allocate an inode blob
* @inode: the inode in need of a blob
*
* Returns 0 if it gets a blob, -ENOMEM otherwise
*/
static int smack_inode_alloc_security(struct inode *inode)
{
inode->i_security = new_inode_smack(smk_of_current());
if (inode->i_security == NULL)
return -ENOMEM;
return 0;
}
/**
* smack_inode_free_security - free an inode blob
* @inode: the inode with a blob
*
* Clears the blob pointer in inode
*/
static void smack_inode_free_security(struct inode *inode)
{
kfree(inode->i_security);
inode->i_security = NULL;
}
/**
* smack_inode_init_security - copy out the smack from an inode
* @inode: the inode
* @dir: unused
* @qstr: unused
* @name: where to put the attribute name
* @value: where to put the attribute value
* @len: where to put the length of the attribute
*
* Returns 0 if it all works out, -ENOMEM if there's no memory
*/
static int smack_inode_init_security(struct inode *inode, struct inode *dir,
const struct qstr *qstr, char **name,
void **value, size_t *len)
{
struct smack_known *skp;
char *csp = smk_of_current();
char *isp = smk_of_inode(inode);
char *dsp = smk_of_inode(dir);
int may;
if (name) {
*name = kstrdup(XATTR_SMACK_SUFFIX, GFP_KERNEL);
if (*name == NULL)
return -ENOMEM;
}
if (value) {
skp = smk_find_entry(csp);
rcu_read_lock();
may = smk_access_entry(csp, dsp, &skp->smk_rules);
rcu_read_unlock();
/*
* If the access rule allows transmutation and
* the directory requests transmutation then
* by all means transmute.
*/
if (may > 0 && ((may & MAY_TRANSMUTE) != 0) &&
smk_inode_transmutable(dir))
isp = dsp;
*value = kstrdup(isp, GFP_KERNEL);
if (*value == NULL)
return -ENOMEM;
}
if (len)
*len = strlen(isp) + 1;
return 0;
}
/**
* smack_inode_link - Smack check on link
* @old_dentry: the existing object
* @dir: unused
* @new_dentry: the new object
*
* Returns 0 if access is permitted, an error code otherwise
*/
static int smack_inode_link(struct dentry *old_dentry, struct inode *dir,
struct dentry *new_dentry)
{
char *isp;
struct smk_audit_info ad;
int rc;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
smk_ad_setfield_u_fs_path_dentry(&ad, old_dentry);
isp = smk_of_inode(old_dentry->d_inode);
rc = smk_curacc(isp, MAY_WRITE, &ad);
if (rc == 0 && new_dentry->d_inode != NULL) {
isp = smk_of_inode(new_dentry->d_inode);
smk_ad_setfield_u_fs_path_dentry(&ad, new_dentry);
rc = smk_curacc(isp, MAY_WRITE, &ad);
}
return rc;
}
/**
* smack_inode_unlink - Smack check on inode deletion
* @dir: containing directory object
* @dentry: file to unlink
*
* Returns 0 if current can write the containing directory
* and the object, error code otherwise
*/
static int smack_inode_unlink(struct inode *dir, struct dentry *dentry)
{
struct inode *ip = dentry->d_inode;
struct smk_audit_info ad;
int rc;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
/*
* You need write access to the thing you're unlinking
*/
rc = smk_curacc(smk_of_inode(ip), MAY_WRITE, &ad);
if (rc == 0) {
/*
* You also need write access to the containing directory
*/
smk_ad_setfield_u_fs_path_dentry(&ad, NULL);
smk_ad_setfield_u_fs_inode(&ad, dir);
rc = smk_curacc(smk_of_inode(dir), MAY_WRITE, &ad);
}
return rc;
}
/**
* smack_inode_rmdir - Smack check on directory deletion
* @dir: containing directory object
* @dentry: directory to unlink
*
* Returns 0 if current can write the containing directory
* and the directory, error code otherwise
*/
static int smack_inode_rmdir(struct inode *dir, struct dentry *dentry)
{
struct smk_audit_info ad;
int rc;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
/*
* You need write access to the thing you're removing
*/
rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);
if (rc == 0) {
/*
* You also need write access to the containing directory
*/
smk_ad_setfield_u_fs_path_dentry(&ad, NULL);
smk_ad_setfield_u_fs_inode(&ad, dir);
rc = smk_curacc(smk_of_inode(dir), MAY_WRITE, &ad);
}
return rc;
}
/**
* smack_inode_rename - Smack check on rename
* @old_inode: the old directory
* @old_dentry: unused
* @new_inode: the new directory
* @new_dentry: unused
*
* Read and write access is required on both the old and
* new directories.
*
* Returns 0 if access is permitted, an error code otherwise
*/
static int smack_inode_rename(struct inode *old_inode,
struct dentry *old_dentry,
struct inode *new_inode,
struct dentry *new_dentry)
{
int rc;
char *isp;
struct smk_audit_info ad;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
smk_ad_setfield_u_fs_path_dentry(&ad, old_dentry);
isp = smk_of_inode(old_dentry->d_inode);
rc = smk_curacc(isp, MAY_READWRITE, &ad);
if (rc == 0 && new_dentry->d_inode != NULL) {
isp = smk_of_inode(new_dentry->d_inode);
smk_ad_setfield_u_fs_path_dentry(&ad, new_dentry);
rc = smk_curacc(isp, MAY_READWRITE, &ad);
}
return rc;
}
/**
* smack_inode_permission - Smack version of permission()
* @inode: the inode in question
* @mask: the access requested
*
* This is the important Smack hook.
*
* Returns 0 if access is permitted, -EACCES otherwise
*/
static int smack_inode_permission(struct inode *inode, int mask)
{
struct smk_audit_info ad;
int no_block = mask & MAY_NOT_BLOCK;
mask &= (MAY_READ|MAY_WRITE|MAY_EXEC|MAY_APPEND);
/*
* No permission to check. Existence test. Yup, it's there.
*/
if (mask == 0)
return 0;
/* May be droppable after audit */
if (no_block)
return -ECHILD;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_INODE);
smk_ad_setfield_u_fs_inode(&ad, inode);
return smk_curacc(smk_of_inode(inode), mask, &ad);
}
/**
* smack_inode_setattr - Smack check for setting attributes
* @dentry: the object
* @iattr: for the force flag
*
* Returns 0 if access is permitted, an error code otherwise
*/
static int smack_inode_setattr(struct dentry *dentry, struct iattr *iattr)
{
struct smk_audit_info ad;
/*
* Need to allow for clearing the setuid bit.
*/
if (iattr->ia_valid & ATTR_FORCE)
return 0;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
return smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);
}
/**
* smack_inode_getattr - Smack check for getting attributes
* @mnt: unused
* @dentry: the object
*
* Returns 0 if access is permitted, an error code otherwise
*/
static int smack_inode_getattr(struct vfsmount *mnt, struct dentry *dentry)
{
struct smk_audit_info ad;
struct path path;
path.dentry = dentry;
path.mnt = mnt;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
smk_ad_setfield_u_fs_path(&ad, path);
return smk_curacc(smk_of_inode(dentry->d_inode), MAY_READ, &ad);
}
/**
* smack_inode_setxattr - Smack check for setting xattrs
* @dentry: the object
* @name: name of the attribute
* @value: unused
* @size: unused
* @flags: unused
*
* This protects the Smack attribute explicitly.
*
* Returns 0 if access is permitted, an error code otherwise
*/
static int smack_inode_setxattr(struct dentry *dentry, const char *name,
const void *value, size_t size, int flags)
{
struct smk_audit_info ad;
int rc = 0;
if (strcmp(name, XATTR_NAME_SMACK) == 0 ||
strcmp(name, XATTR_NAME_SMACKIPIN) == 0 ||
strcmp(name, XATTR_NAME_SMACKIPOUT) == 0 ||
strcmp(name, XATTR_NAME_SMACKEXEC) == 0 ||
strcmp(name, XATTR_NAME_SMACKMMAP) == 0) {
if (!capable(CAP_MAC_ADMIN))
rc = -EPERM;
/*
* check label validity here so import wont fail on
* post_setxattr
*/
if (size == 0 || size >= SMK_LABELLEN ||
smk_import(value, size) == NULL)
rc = -EINVAL;
} else if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0) {
if (!capable(CAP_MAC_ADMIN))
rc = -EPERM;
if (size != TRANS_TRUE_SIZE ||
strncmp(value, TRANS_TRUE, TRANS_TRUE_SIZE) != 0)
rc = -EINVAL;
} else
rc = cap_inode_setxattr(dentry, name, value, size, flags);
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
if (rc == 0)
rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);
return rc;
}
/**
* smack_inode_post_setxattr - Apply the Smack update approved above
* @dentry: object
* @name: attribute name
* @value: attribute value
* @size: attribute size
* @flags: unused
*
* Set the pointer in the inode blob to the entry found
* in the master label list.
*/
static void smack_inode_post_setxattr(struct dentry *dentry, const char *name,
const void *value, size_t size, int flags)
{
char *nsp;
struct inode_smack *isp = dentry->d_inode->i_security;
if (strcmp(name, XATTR_NAME_SMACK) == 0) {
nsp = smk_import(value, size);
if (nsp != NULL)
isp->smk_inode = nsp;
else
isp->smk_inode = smack_known_invalid.smk_known;
} else if (strcmp(name, XATTR_NAME_SMACKEXEC) == 0) {
nsp = smk_import(value, size);
if (nsp != NULL)
isp->smk_task = nsp;
else
isp->smk_task = smack_known_invalid.smk_known;
} else if (strcmp(name, XATTR_NAME_SMACKMMAP) == 0) {
nsp = smk_import(value, size);
if (nsp != NULL)
isp->smk_mmap = nsp;
else
isp->smk_mmap = smack_known_invalid.smk_known;
} else if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0)
isp->smk_flags |= SMK_INODE_TRANSMUTE;
return;
}
/**
* smack_inode_getxattr - Smack check on getxattr
* @dentry: the object
* @name: unused
*
* Returns 0 if access is permitted, an error code otherwise
*/
static int smack_inode_getxattr(struct dentry *dentry, const char *name)
{
struct smk_audit_info ad;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
return smk_curacc(smk_of_inode(dentry->d_inode), MAY_READ, &ad);
}
/**
* smack_inode_removexattr - Smack check on removexattr
* @dentry: the object
* @name: name of the attribute
*
* Removing the Smack attribute requires CAP_MAC_ADMIN
*
* Returns 0 if access is permitted, an error code otherwise
*/
static int smack_inode_removexattr(struct dentry *dentry, const char *name)
{
struct inode_smack *isp;
struct smk_audit_info ad;
int rc = 0;
if (strcmp(name, XATTR_NAME_SMACK) == 0 ||
strcmp(name, XATTR_NAME_SMACKIPIN) == 0 ||
strcmp(name, XATTR_NAME_SMACKIPOUT) == 0 ||
strcmp(name, XATTR_NAME_SMACKEXEC) == 0 ||
strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0 ||
strcmp(name, XATTR_NAME_SMACKMMAP)) {
if (!capable(CAP_MAC_ADMIN))
rc = -EPERM;
} else
rc = cap_inode_removexattr(dentry, name);
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
if (rc == 0)
rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);
if (rc == 0) {
isp = dentry->d_inode->i_security;
isp->smk_task = NULL;
isp->smk_mmap = NULL;
}
return rc;
}
/**
* smack_inode_getsecurity - get smack xattrs
* @inode: the object
* @name: attribute name
* @buffer: where to put the result
* @alloc: unused
*
* Returns the size of the attribute or an error code
*/
static int smack_inode_getsecurity(const struct inode *inode,
const char *name, void **buffer,
bool alloc)
{
struct socket_smack *ssp;
struct socket *sock;
struct super_block *sbp;
struct inode *ip = (struct inode *)inode;
char *isp;
int ilen;
int rc = 0;
if (strcmp(name, XATTR_SMACK_SUFFIX) == 0) {
isp = smk_of_inode(inode);
ilen = strlen(isp) + 1;
*buffer = isp;
return ilen;
}
/*
* The rest of the Smack xattrs are only on sockets.
*/
sbp = ip->i_sb;
if (sbp->s_magic != SOCKFS_MAGIC)
return -EOPNOTSUPP;
sock = SOCKET_I(ip);
if (sock == NULL || sock->sk == NULL)
return -EOPNOTSUPP;
ssp = sock->sk->sk_security;
if (strcmp(name, XATTR_SMACK_IPIN) == 0)
isp = ssp->smk_in;
else if (strcmp(name, XATTR_SMACK_IPOUT) == 0)
isp = ssp->smk_out;
else
return -EOPNOTSUPP;
ilen = strlen(isp) + 1;
if (rc == 0) {
*buffer = isp;
rc = ilen;
}
return rc;
}
/**
* smack_inode_listsecurity - list the Smack attributes
* @inode: the object
* @buffer: where they go
* @buffer_size: size of buffer
*
* Returns 0 on success, -EINVAL otherwise
*/
static int smack_inode_listsecurity(struct inode *inode, char *buffer,
size_t buffer_size)
{
int len = strlen(XATTR_NAME_SMACK);
if (buffer != NULL && len <= buffer_size) {
memcpy(buffer, XATTR_NAME_SMACK, len);
return len;
}
return -EINVAL;
}
/**
* smack_inode_getsecid - Extract inode's security id
* @inode: inode to extract the info from
* @secid: where result will be saved
*/
static void smack_inode_getsecid(const struct inode *inode, u32 *secid)
{
struct inode_smack *isp = inode->i_security;
*secid = smack_to_secid(isp->smk_inode);
}
/*
* File Hooks
*/
/**
* smack_file_permission - Smack check on file operations
* @file: unused
* @mask: unused
*
* Returns 0
*
* Should access checks be done on each read or write?
* UNICOS and SELinux say yes.
* Trusted Solaris, Trusted Irix, and just about everyone else says no.
*
* I'll say no for now. Smack does not do the frequent
* label changing that SELinux does.
*/
static int smack_file_permission(struct file *file, int mask)
{
return 0;
}
/**
* smack_file_alloc_security - assign a file security blob
* @file: the object
*
* The security blob for a file is a pointer to the master
* label list, so no allocation is done.
*
* Returns 0
*/
static int smack_file_alloc_security(struct file *file)
{
file->f_security = smk_of_current();
return 0;
}
/**
* smack_file_free_security - clear a file security blob
* @file: the object
*
* The security blob for a file is a pointer to the master
* label list, so no memory is freed.
*/
static void smack_file_free_security(struct file *file)
{
file->f_security = NULL;
}
/**
* smack_file_ioctl - Smack check on ioctls
* @file: the object
* @cmd: what to do
* @arg: unused
*
* Relies heavily on the correct use of the ioctl command conventions.
*
* Returns 0 if allowed, error code otherwise
*/
static int smack_file_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
int rc = 0;
struct smk_audit_info ad;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
smk_ad_setfield_u_fs_path(&ad, file->f_path);
if (_IOC_DIR(cmd) & _IOC_WRITE)
rc = smk_curacc(file->f_security, MAY_WRITE, &ad);
if (rc == 0 && (_IOC_DIR(cmd) & _IOC_READ))
rc = smk_curacc(file->f_security, MAY_READ, &ad);
return rc;
}
/**
* smack_file_lock - Smack check on file locking
* @file: the object
* @cmd: unused
*
* Returns 0 if current has write access, error code otherwise
*/
static int smack_file_lock(struct file *file, unsigned int cmd)
{
struct smk_audit_info ad;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
smk_ad_setfield_u_fs_path(&ad, file->f_path);
return smk_curacc(file->f_security, MAY_WRITE, &ad);
}
/**
* smack_file_fcntl - Smack check on fcntl
* @file: the object
* @cmd: what action to check
* @arg: unused
*
* Generally these operations are harmless.
* File locking operations present an obvious mechanism
* for passing information, so they require write access.
*
* Returns 0 if current has access, error code otherwise
*/
static int smack_file_fcntl(struct file *file, unsigned int cmd,
unsigned long arg)
{
struct smk_audit_info ad;
int rc = 0;
switch (cmd) {
case F_GETLK:
case F_SETLK:
case F_SETLKW:
case F_SETOWN:
case F_SETSIG:
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
smk_ad_setfield_u_fs_path(&ad, file->f_path);
rc = smk_curacc(file->f_security, MAY_WRITE, &ad);
break;
default:
break;
}
return rc;
}
/**
* smack_file_mmap :
* Check permissions for a mmap operation. The @file may be NULL, e.g.
* if mapping anonymous memory.
* @file contains the file structure for file to map (may be NULL).
* @reqprot contains the protection requested by the application.
* @prot contains the protection that will be applied by the kernel.
* @flags contains the operational flags.
* Return 0 if permission is granted.
*/
static int smack_file_mmap(struct file *file,
unsigned long reqprot, unsigned long prot,
unsigned long flags, unsigned long addr,
unsigned long addr_only)
{
struct smack_known *skp;
struct smack_rule *srp;
struct task_smack *tsp;
char *sp;
char *msmack;
char *osmack;
struct inode_smack *isp;
struct dentry *dp;
int may;
int mmay;
int tmay;
int rc;
/* do DAC check on address space usage */
rc = cap_file_mmap(file, reqprot, prot, flags, addr, addr_only);
if (rc || addr_only)
return rc;
if (file == NULL || file->f_dentry == NULL)
return 0;
dp = file->f_dentry;
if (dp->d_inode == NULL)
return 0;
isp = dp->d_inode->i_security;
if (isp->smk_mmap == NULL)
return 0;
msmack = isp->smk_mmap;
tsp = current_security();
sp = smk_of_current();
skp = smk_find_entry(sp);
rc = 0;
rcu_read_lock();
/*
* For each Smack rule associated with the subject
* label verify that the SMACK64MMAP also has access
* to that rule's object label.
*/
list_for_each_entry_rcu(srp, &skp->smk_rules, list) {
osmack = srp->smk_object;
/*
* Matching labels always allows access.
*/
if (msmack == osmack)
continue;
/*
* If there is a matching local rule take
* that into account as well.
*/
may = smk_access_entry(srp->smk_subject, osmack,
&tsp->smk_rules);
if (may == -ENOENT)
may = srp->smk_access;
else
may &= srp->smk_access;
/*
* If may is zero the SMACK64MMAP subject can't
* possibly have less access.
*/
if (may == 0)
continue;
/*
* Fetch the global list entry.
* If there isn't one a SMACK64MMAP subject
* can't have as much access as current.
*/
skp = smk_find_entry(msmack);
mmay = smk_access_entry(msmack, osmack, &skp->smk_rules);
if (mmay == -ENOENT) {
rc = -EACCES;
break;
}
/*
* If there is a local entry it modifies the
* potential access, too.
*/
tmay = smk_access_entry(msmack, osmack, &tsp->smk_rules);
if (tmay != -ENOENT)
mmay &= tmay;
/*
* If there is any access available to current that is
* not available to a SMACK64MMAP subject
* deny access.
*/
if ((may | mmay) != mmay) {
rc = -EACCES;
break;
}
}
rcu_read_unlock();
return rc;
}
/**
* smack_file_set_fowner - set the file security blob value
* @file: object in question
*
* Returns 0
* Further research may be required on this one.
*/
static int smack_file_set_fowner(struct file *file)
{
file->f_security = smk_of_current();
return 0;
}
/**
* smack_file_send_sigiotask - Smack on sigio
* @tsk: The target task
* @fown: the object the signal come from
* @signum: unused
*
* Allow a privileged task to get signals even if it shouldn't
*
* Returns 0 if a subject with the object's smack could
* write to the task, an error code otherwise.
*/
static int smack_file_send_sigiotask(struct task_struct *tsk,
struct fown_struct *fown, int signum)
{
struct file *file;
int rc;
char *tsp = smk_of_task(tsk->cred->security);
struct smk_audit_info ad;
/*
* struct fown_struct is never outside the context of a struct file
*/
file = container_of(fown, struct file, f_owner);
/* we don't log here as rc can be overriden */
rc = smk_access(file->f_security, tsp, MAY_WRITE, NULL);
if (rc != 0 && has_capability(tsk, CAP_MAC_OVERRIDE))
rc = 0;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
smk_ad_setfield_u_tsk(&ad, tsk);
smack_log(file->f_security, tsp, MAY_WRITE, rc, &ad);
return rc;
}
/**
* smack_file_receive - Smack file receive check
* @file: the object
*
* Returns 0 if current has access, error code otherwise
*/
static int smack_file_receive(struct file *file)
{
int may = 0;
struct smk_audit_info ad;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
smk_ad_setfield_u_fs_path(&ad, file->f_path);
/*
* This code relies on bitmasks.
*/
if (file->f_mode & FMODE_READ)
may = MAY_READ;
if (file->f_mode & FMODE_WRITE)
may |= MAY_WRITE;
return smk_curacc(file->f_security, may, &ad);
}
/**
* smack_dentry_open - Smack dentry open processing
* @file: the object
* @cred: unused
*
* Set the security blob in the file structure.
*
* Returns 0
*/
static int smack_dentry_open(struct file *file, const struct cred *cred)
{
struct inode_smack *isp = file->f_path.dentry->d_inode->i_security;
file->f_security = isp->smk_inode;
return 0;
}
/*
* Task hooks
*/
/**
* smack_cred_alloc_blank - "allocate" blank task-level security credentials
* @new: the new credentials
* @gfp: the atomicity of any memory allocations
*
* Prepare a blank set of credentials for modification. This must allocate all
* the memory the LSM module might require such that cred_transfer() can
* complete without error.
*/
static int smack_cred_alloc_blank(struct cred *cred, gfp_t gfp)
{
struct task_smack *tsp;
tsp = new_task_smack(NULL, NULL, gfp);
if (tsp == NULL)
return -ENOMEM;
cred->security = tsp;
return 0;
}
/**
* smack_cred_free - "free" task-level security credentials
* @cred: the credentials in question
*
*/
static void smack_cred_free(struct cred *cred)
{
struct task_smack *tsp = cred->security;
struct smack_rule *rp;
struct list_head *l;
struct list_head *n;
if (tsp == NULL)
return;
cred->security = NULL;
list_for_each_safe(l, n, &tsp->smk_rules) {
rp = list_entry(l, struct smack_rule, list);
list_del(&rp->list);
kfree(rp);
}
kfree(tsp);
}
/**
* smack_cred_prepare - prepare new set of credentials for modification
* @new: the new credentials
* @old: the original credentials
* @gfp: the atomicity of any memory allocations
*
* Prepare a new set of credentials for modification.
*/
static int smack_cred_prepare(struct cred *new, const struct cred *old,
gfp_t gfp)
{
struct task_smack *old_tsp = old->security;
struct task_smack *new_tsp;
int rc;
new_tsp = new_task_smack(old_tsp->smk_task, old_tsp->smk_task, gfp);
if (new_tsp == NULL)
return -ENOMEM;
rc = smk_copy_rules(&new_tsp->smk_rules, &old_tsp->smk_rules, gfp);
if (rc != 0)
return rc;
new->security = new_tsp;
return 0;
}
/**
* smack_cred_transfer - Transfer the old credentials to the new credentials
* @new: the new credentials
* @old: the original credentials
*
* Fill in a set of blank credentials from another set of credentials.
*/
static void smack_cred_transfer(struct cred *new, const struct cred *old)
{
struct task_smack *old_tsp = old->security;
struct task_smack *new_tsp = new->security;
new_tsp->smk_task = old_tsp->smk_task;
new_tsp->smk_forked = old_tsp->smk_task;
mutex_init(&new_tsp->smk_rules_lock);
INIT_LIST_HEAD(&new_tsp->smk_rules);
/* cbs copy rule list */
}
/**
* smack_kernel_act_as - Set the subjective context in a set of credentials
* @new: points to the set of credentials to be modified.
* @secid: specifies the security ID to be set
*
* Set the security data for a kernel service.
*/
static int smack_kernel_act_as(struct cred *new, u32 secid)
{
struct task_smack *new_tsp = new->security;
char *smack = smack_from_secid(secid);
if (smack == NULL)
return -EINVAL;
new_tsp->smk_task = smack;
return 0;
}
/**
* smack_kernel_create_files_as - Set the file creation label in a set of creds
* @new: points to the set of credentials to be modified
* @inode: points to the inode to use as a reference
*
* Set the file creation context in a set of credentials to the same
* as the objective context of the specified inode
*/
static int smack_kernel_create_files_as(struct cred *new,
struct inode *inode)
{
struct inode_smack *isp = inode->i_security;
struct task_smack *tsp = new->security;
tsp->smk_forked = isp->smk_inode;
tsp->smk_task = isp->smk_inode;
return 0;
}
/**
* smk_curacc_on_task - helper to log task related access
* @p: the task object
* @access: the access requested
* @caller: name of the calling function for audit
*
* Return 0 if access is permitted
*/
static int smk_curacc_on_task(struct task_struct *p, int access,
const char *caller)
{
struct smk_audit_info ad;
smk_ad_init(&ad, caller, LSM_AUDIT_DATA_TASK);
smk_ad_setfield_u_tsk(&ad, p);
return smk_curacc(smk_of_task(task_security(p)), access, &ad);
}
/**
* smack_task_setpgid - Smack check on setting pgid
* @p: the task object
* @pgid: unused
*
* Return 0 if write access is permitted
*/
static int smack_task_setpgid(struct task_struct *p, pid_t pgid)
{
return smk_curacc_on_task(p, MAY_WRITE, __func__);
}
/**
* smack_task_getpgid - Smack access check for getpgid
* @p: the object task
*
* Returns 0 if current can read the object task, error code otherwise
*/
static int smack_task_getpgid(struct task_struct *p)
{
return smk_curacc_on_task(p, MAY_READ, __func__);
}
/**
* smack_task_getsid - Smack access check for getsid
* @p: the object task
*
* Returns 0 if current can read the object task, error code otherwise
*/
static int smack_task_getsid(struct task_struct *p)
{
return smk_curacc_on_task(p, MAY_READ, __func__);
}
/**
* smack_task_getsecid - get the secid of the task
* @p: the object task
* @secid: where to put the result
*
* Sets the secid to contain a u32 version of the smack label.
*/
static void smack_task_getsecid(struct task_struct *p, u32 *secid)
{
*secid = smack_to_secid(smk_of_task(task_security(p)));
}
/**
* smack_task_setnice - Smack check on setting nice
* @p: the task object
* @nice: unused
*
* Return 0 if write access is permitted
*/
static int smack_task_setnice(struct task_struct *p, int nice)
{
int rc;
rc = cap_task_setnice(p, nice);
if (rc == 0)
rc = smk_curacc_on_task(p, MAY_WRITE, __func__);
return rc;
}
/**
* smack_task_setioprio - Smack check on setting ioprio
* @p: the task object
* @ioprio: unused
*
* Return 0 if write access is permitted
*/
static int smack_task_setioprio(struct task_struct *p, int ioprio)
{
int rc;
rc = cap_task_setioprio(p, ioprio);
if (rc == 0)
rc = smk_curacc_on_task(p, MAY_WRITE, __func__);
return rc;
}
/**
* smack_task_getioprio - Smack check on reading ioprio
* @p: the task object
*
* Return 0 if read access is permitted
*/
static int smack_task_getioprio(struct task_struct *p)
{
return smk_curacc_on_task(p, MAY_READ, __func__);
}
/**
* smack_task_setscheduler - Smack check on setting scheduler
* @p: the task object
* @policy: unused
* @lp: unused
*
* Return 0 if read access is permitted
*/
static int smack_task_setscheduler(struct task_struct *p)
{
int rc;
rc = cap_task_setscheduler(p);
if (rc == 0)
rc = smk_curacc_on_task(p, MAY_WRITE, __func__);
return rc;
}
/**
* smack_task_getscheduler - Smack check on reading scheduler
* @p: the task object
*
* Return 0 if read access is permitted
*/
static int smack_task_getscheduler(struct task_struct *p)
{
return smk_curacc_on_task(p, MAY_READ, __func__);
}
/**
* smack_task_movememory - Smack check on moving memory
* @p: the task object
*
* Return 0 if write access is permitted
*/
static int smack_task_movememory(struct task_struct *p)
{
return smk_curacc_on_task(p, MAY_WRITE, __func__);
}
/**
* smack_task_kill - Smack check on signal delivery
* @p: the task object
* @info: unused
* @sig: unused
* @secid: identifies the smack to use in lieu of current's
*
* Return 0 if write access is permitted
*
* The secid behavior is an artifact of an SELinux hack
* in the USB code. Someday it may go away.
*/
static int smack_task_kill(struct task_struct *p, struct siginfo *info,
int sig, u32 secid)
{
struct smk_audit_info ad;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
smk_ad_setfield_u_tsk(&ad, p);
/*
* Sending a signal requires that the sender
* can write the receiver.
*/
if (secid == 0)
return smk_curacc(smk_of_task(task_security(p)), MAY_WRITE,
&ad);
/*
* If the secid isn't 0 we're dealing with some USB IO
* specific behavior. This is not clean. For one thing
* we can't take privilege into account.
*/
return smk_access(smack_from_secid(secid),
smk_of_task(task_security(p)), MAY_WRITE, &ad);
}
/**
* smack_task_wait - Smack access check for waiting
* @p: task to wait for
*
* Returns 0 if current can wait for p, error code otherwise
*/
static int smack_task_wait(struct task_struct *p)
{
struct smk_audit_info ad;
char *sp = smk_of_current();
char *tsp = smk_of_forked(task_security(p));
int rc;
/* we don't log here, we can be overriden */
rc = smk_access(tsp, sp, MAY_WRITE, NULL);
if (rc == 0)
goto out_log;
/*
* Allow the operation to succeed if either task
* has privilege to perform operations that might
* account for the smack labels having gotten to
* be different in the first place.
*
* This breaks the strict subject/object access
* control ideal, taking the object's privilege
* state into account in the decision as well as
* the smack value.
*/
if (capable(CAP_MAC_OVERRIDE) || has_capability(p, CAP_MAC_OVERRIDE))
rc = 0;
/* we log only if we didn't get overriden */
out_log:
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
smk_ad_setfield_u_tsk(&ad, p);
smack_log(tsp, sp, MAY_WRITE, rc, &ad);
return rc;
}
/**
* smack_task_to_inode - copy task smack into the inode blob
* @p: task to copy from
* @inode: inode to copy to
*
* Sets the smack pointer in the inode security blob
*/
static void smack_task_to_inode(struct task_struct *p, struct inode *inode)
{
struct inode_smack *isp = inode->i_security;
isp->smk_inode = smk_of_task(task_security(p));
}
/*
* Socket hooks.
*/
/**
* smack_sk_alloc_security - Allocate a socket blob
* @sk: the socket
* @family: unused
* @gfp_flags: memory allocation flags
*
* Assign Smack pointers to current
*
* Returns 0 on success, -ENOMEM is there's no memory
*/
static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags)
{
char *csp = smk_of_current();
struct socket_smack *ssp;
ssp = kzalloc(sizeof(struct socket_smack), gfp_flags);
if (ssp == NULL)
return -ENOMEM;
ssp->smk_in = csp;
ssp->smk_out = csp;
ssp->smk_packet = NULL;
sk->sk_security = ssp;
return 0;
}
/**
* smack_sk_free_security - Free a socket blob
* @sk: the socket
*
* Clears the blob pointer
*/
static void smack_sk_free_security(struct sock *sk)
{
kfree(sk->sk_security);
}
/**
* smack_host_label - check host based restrictions
* @sip: the object end
*
* looks for host based access restrictions
*
* This version will only be appropriate for really small sets of single label
* hosts. The caller is responsible for ensuring that the RCU read lock is
* taken before calling this function.
*
* Returns the label of the far end or NULL if it's not special.
*/
static char *smack_host_label(struct sockaddr_in *sip)
{
struct smk_netlbladdr *snp;
struct in_addr *siap = &sip->sin_addr;
if (siap->s_addr == 0)
return NULL;
list_for_each_entry_rcu(snp, &smk_netlbladdr_list, list)
/*
* we break after finding the first match because
* the list is sorted from longest to shortest mask
* so we have found the most specific match
*/
if ((&snp->smk_host.sin_addr)->s_addr ==
(siap->s_addr & (&snp->smk_mask)->s_addr)) {
/* we have found the special CIPSO option */
if (snp->smk_label == smack_cipso_option)
return NULL;
return snp->smk_label;
}
return NULL;
}
/**
* smack_set_catset - convert a capset to netlabel mls categories
* @catset: the Smack categories
* @sap: where to put the netlabel categories
*
* Allocates and fills attr.mls.cat
*/
static void smack_set_catset(char *catset, struct netlbl_lsm_secattr *sap)
{
unsigned char *cp;
unsigned char m;
int cat;
int rc;
int byte;
if (!catset)
return;
sap->flags |= NETLBL_SECATTR_MLS_CAT;
sap->attr.mls.cat = netlbl_secattr_catmap_alloc(GFP_ATOMIC);
sap->attr.mls.cat->startbit = 0;
for (cat = 1, cp = catset, byte = 0; byte < SMK_LABELLEN; cp++, byte++)
for (m = 0x80; m != 0; m >>= 1, cat++) {
if ((m & *cp) == 0)
continue;
rc = netlbl_secattr_catmap_setbit(sap->attr.mls.cat,
cat, GFP_ATOMIC);
}
}
/**
* smack_to_secattr - fill a secattr from a smack value
* @smack: the smack value
* @nlsp: where the result goes
*
* Casey says that CIPSO is good enough for now.
* It can be used to effect.
* It can also be abused to effect when necessary.
* Apologies to the TSIG group in general and GW in particular.
*/
static void smack_to_secattr(char *smack, struct netlbl_lsm_secattr *nlsp)
{
struct smack_cipso cipso;
int rc;
nlsp->domain = smack;
nlsp->flags = NETLBL_SECATTR_DOMAIN | NETLBL_SECATTR_MLS_LVL;
rc = smack_to_cipso(smack, &cipso);
if (rc == 0) {
nlsp->attr.mls.lvl = cipso.smk_level;
smack_set_catset(cipso.smk_catset, nlsp);
} else {
nlsp->attr.mls.lvl = smack_cipso_direct;
smack_set_catset(smack, nlsp);
}
}
/**
* smack_netlabel - Set the secattr on a socket
* @sk: the socket
* @labeled: socket label scheme
*
* Convert the outbound smack value (smk_out) to a
* secattr and attach it to the socket.
*
* Returns 0 on success or an error code
*/
static int smack_netlabel(struct sock *sk, int labeled)
{
struct socket_smack *ssp = sk->sk_security;
struct netlbl_lsm_secattr secattr;
int rc = 0;
/*
* Usually the netlabel code will handle changing the
* packet labeling based on the label.
* The case of a single label host is different, because
* a single label host should never get a labeled packet
* even though the label is usually associated with a packet
* label.
*/
local_bh_disable();
bh_lock_sock_nested(sk);
if (ssp->smk_out == smack_net_ambient ||
labeled == SMACK_UNLABELED_SOCKET)
netlbl_sock_delattr(sk);
else {
netlbl_secattr_init(&secattr);
smack_to_secattr(ssp->smk_out, &secattr);
rc = netlbl_sock_setattr(sk, sk->sk_family, &secattr);
netlbl_secattr_destroy(&secattr);
}
bh_unlock_sock(sk);
local_bh_enable();
return rc;
}
/**
* smack_netlbel_send - Set the secattr on a socket and perform access checks
* @sk: the socket
* @sap: the destination address
*
* Set the correct secattr for the given socket based on the destination
* address and perform any outbound access checks needed.
*
* Returns 0 on success or an error code.
*
*/
static int smack_netlabel_send(struct sock *sk, struct sockaddr_in *sap)
{
int rc;
int sk_lbl;
char *hostsp;
struct socket_smack *ssp = sk->sk_security;
struct smk_audit_info ad;
rcu_read_lock();
hostsp = smack_host_label(sap);
if (hostsp != NULL) {
sk_lbl = SMACK_UNLABELED_SOCKET;
#ifdef CONFIG_AUDIT
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_NET);
ad.a.u.net.family = sap->sin_family;
ad.a.u.net.dport = sap->sin_port;
ad.a.u.net.v4info.daddr = sap->sin_addr.s_addr;
#endif
rc = smk_access(ssp->smk_out, hostsp, MAY_WRITE, &ad);
} else {
sk_lbl = SMACK_CIPSO_SOCKET;
rc = 0;
}
rcu_read_unlock();
if (rc != 0)
return rc;
return smack_netlabel(sk, sk_lbl);
}
/**
* smack_inode_setsecurity - set smack xattrs
* @inode: the object
* @name: attribute name
* @value: attribute value
* @size: size of the attribute
* @flags: unused
*
* Sets the named attribute in the appropriate blob
*
* Returns 0 on success, or an error code
*/
static int smack_inode_setsecurity(struct inode *inode, const char *name,
const void *value, size_t size, int flags)
{
char *sp;
struct inode_smack *nsp = inode->i_security;
struct socket_smack *ssp;
struct socket *sock;
int rc = 0;
if (value == NULL || size > SMK_LABELLEN || size == 0)
return -EACCES;
sp = smk_import(value, size);
if (sp == NULL)
return -EINVAL;
if (strcmp(name, XATTR_SMACK_SUFFIX) == 0) {
nsp->smk_inode = sp;
nsp->smk_flags |= SMK_INODE_INSTANT;
return 0;
}
/*
* The rest of the Smack xattrs are only on sockets.
*/
if (inode->i_sb->s_magic != SOCKFS_MAGIC)
return -EOPNOTSUPP;
sock = SOCKET_I(inode);
if (sock == NULL || sock->sk == NULL)
return -EOPNOTSUPP;
ssp = sock->sk->sk_security;
if (strcmp(name, XATTR_SMACK_IPIN) == 0)
ssp->smk_in = sp;
else if (strcmp(name, XATTR_SMACK_IPOUT) == 0) {
ssp->smk_out = sp;
if (sock->sk->sk_family != PF_UNIX) {
rc = smack_netlabel(sock->sk, SMACK_CIPSO_SOCKET);
if (rc != 0)
printk(KERN_WARNING
"Smack: \"%s\" netlbl error %d.\n",
__func__, -rc);
}
} else
return -EOPNOTSUPP;
return 0;
}
/**
* smack_socket_post_create - finish socket setup
* @sock: the socket
* @family: protocol family
* @type: unused
* @protocol: unused
* @kern: unused
*
* Sets the netlabel information on the socket
*
* Returns 0 on success, and error code otherwise
*/
static int smack_socket_post_create(struct socket *sock, int family,
int type, int protocol, int kern)
{
if (family != PF_INET || sock->sk == NULL)
return 0;
/*
* Set the outbound netlbl.
*/
return smack_netlabel(sock->sk, SMACK_CIPSO_SOCKET);
}
/**
* smack_socket_connect - connect access check
* @sock: the socket
* @sap: the other end
* @addrlen: size of sap
*
* Verifies that a connection may be possible
*
* Returns 0 on success, and error code otherwise
*/
static int smack_socket_connect(struct socket *sock, struct sockaddr *sap,
int addrlen)
{
if (sock->sk == NULL || sock->sk->sk_family != PF_INET)
return 0;
if (addrlen < sizeof(struct sockaddr_in))
return -EINVAL;
return smack_netlabel_send(sock->sk, (struct sockaddr_in *)sap);
}
/**
* smack_flags_to_may - convert S_ to MAY_ values
* @flags: the S_ value
*
* Returns the equivalent MAY_ value
*/
static int smack_flags_to_may(int flags)
{
int may = 0;
if (flags & S_IRUGO)
may |= MAY_READ;
if (flags & S_IWUGO)
may |= MAY_WRITE;
if (flags & S_IXUGO)
may |= MAY_EXEC;
return may;
}
/**
* smack_msg_msg_alloc_security - Set the security blob for msg_msg
* @msg: the object
*
* Returns 0
*/
static int smack_msg_msg_alloc_security(struct msg_msg *msg)
{
msg->security = smk_of_current();
return 0;
}
/**
* smack_msg_msg_free_security - Clear the security blob for msg_msg
* @msg: the object
*
* Clears the blob pointer
*/
static void smack_msg_msg_free_security(struct msg_msg *msg)
{
msg->security = NULL;
}
/**
* smack_of_shm - the smack pointer for the shm
* @shp: the object
*
* Returns a pointer to the smack value
*/
static char *smack_of_shm(struct shmid_kernel *shp)
{
return (char *)shp->shm_perm.security;
}
/**
* smack_shm_alloc_security - Set the security blob for shm
* @shp: the object
*
* Returns 0
*/
static int smack_shm_alloc_security(struct shmid_kernel *shp)
{
struct kern_ipc_perm *isp = &shp->shm_perm;
isp->security = smk_of_current();
return 0;
}
/**
* smack_shm_free_security - Clear the security blob for shm
* @shp: the object
*
* Clears the blob pointer
*/
static void smack_shm_free_security(struct shmid_kernel *shp)
{
struct kern_ipc_perm *isp = &shp->shm_perm;
isp->security = NULL;
}
/**
* smk_curacc_shm : check if current has access on shm
* @shp : the object
* @access : access requested
*
* Returns 0 if current has the requested access, error code otherwise
*/
static int smk_curacc_shm(struct shmid_kernel *shp, int access)
{
char *ssp = smack_of_shm(shp);
struct smk_audit_info ad;
#ifdef CONFIG_AUDIT
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
ad.a.u.ipc_id = shp->shm_perm.id;
#endif
return smk_curacc(ssp, access, &ad);
}
/**
* smack_shm_associate - Smack access check for shm
* @shp: the object
* @shmflg: access requested
*
* Returns 0 if current has the requested access, error code otherwise
*/
static int smack_shm_associate(struct shmid_kernel *shp, int shmflg)
{
int may;
may = smack_flags_to_may(shmflg);
return smk_curacc_shm(shp, may);
}
/**
* smack_shm_shmctl - Smack access check for shm
* @shp: the object
* @cmd: what it wants to do
*
* Returns 0 if current has the requested access, error code otherwise
*/
static int smack_shm_shmctl(struct shmid_kernel *shp, int cmd)
{
int may;
switch (cmd) {
case IPC_STAT:
case SHM_STAT:
may = MAY_READ;
break;
case IPC_SET:
case SHM_LOCK:
case SHM_UNLOCK:
case IPC_RMID:
may = MAY_READWRITE;
break;
case IPC_INFO:
case SHM_INFO:
/*
* System level information.
*/
return 0;
default:
return -EINVAL;
}
return smk_curacc_shm(shp, may);
}
/**
* smack_shm_shmat - Smack access for shmat
* @shp: the object
* @shmaddr: unused
* @shmflg: access requested
*
* Returns 0 if current has the requested access, error code otherwise
*/
static int smack_shm_shmat(struct shmid_kernel *shp, char __user *shmaddr,
int shmflg)
{
int may;
may = smack_flags_to_may(shmflg);
return smk_curacc_shm(shp, may);
}
/**
* smack_of_sem - the smack pointer for the sem
* @sma: the object
*
* Returns a pointer to the smack value
*/
static char *smack_of_sem(struct sem_array *sma)
{
return (char *)sma->sem_perm.security;
}
/**
* smack_sem_alloc_security - Set the security blob for sem
* @sma: the object
*
* Returns 0
*/
static int smack_sem_alloc_security(struct sem_array *sma)
{
struct kern_ipc_perm *isp = &sma->sem_perm;
isp->security = smk_of_current();
return 0;
}
/**
* smack_sem_free_security - Clear the security blob for sem
* @sma: the object
*
* Clears the blob pointer
*/
static void smack_sem_free_security(struct sem_array *sma)
{
struct kern_ipc_perm *isp = &sma->sem_perm;
isp->security = NULL;
}
/**
* smk_curacc_sem : check if current has access on sem
* @sma : the object
* @access : access requested
*
* Returns 0 if current has the requested access, error code otherwise
*/
static int smk_curacc_sem(struct sem_array *sma, int access)
{
char *ssp = smack_of_sem(sma);
struct smk_audit_info ad;
#ifdef CONFIG_AUDIT
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
ad.a.u.ipc_id = sma->sem_perm.id;
#endif
return smk_curacc(ssp, access, &ad);
}
/**
* smack_sem_associate - Smack access check for sem
* @sma: the object
* @semflg: access requested
*
* Returns 0 if current has the requested access, error code otherwise
*/
static int smack_sem_associate(struct sem_array *sma, int semflg)
{
int may;
may = smack_flags_to_may(semflg);
return smk_curacc_sem(sma, may);
}
/**
* smack_sem_shmctl - Smack access check for sem
* @sma: the object
* @cmd: what it wants to do
*
* Returns 0 if current has the requested access, error code otherwise
*/
static int smack_sem_semctl(struct sem_array *sma, int cmd)
{
int may;
switch (cmd) {
case GETPID:
case GETNCNT:
case GETZCNT:
case GETVAL:
case GETALL:
case IPC_STAT:
case SEM_STAT:
may = MAY_READ;
break;
case SETVAL:
case SETALL:
case IPC_RMID:
case IPC_SET:
may = MAY_READWRITE;
break;
case IPC_INFO:
case SEM_INFO:
/*
* System level information
*/
return 0;
default:
return -EINVAL;
}
return smk_curacc_sem(sma, may);
}
/**
* smack_sem_semop - Smack checks of semaphore operations
* @sma: the object
* @sops: unused
* @nsops: unused
* @alter: unused
*
* Treated as read and write in all cases.
*
* Returns 0 if access is allowed, error code otherwise
*/
static int smack_sem_semop(struct sem_array *sma, struct sembuf *sops,
unsigned nsops, int alter)
{
return smk_curacc_sem(sma, MAY_READWRITE);
}
/**
* smack_msg_alloc_security - Set the security blob for msg
* @msq: the object
*
* Returns 0
*/
static int smack_msg_queue_alloc_security(struct msg_queue *msq)
{
struct kern_ipc_perm *kisp = &msq->q_perm;
kisp->security = smk_of_current();
return 0;
}
/**
* smack_msg_free_security - Clear the security blob for msg
* @msq: the object
*
* Clears the blob pointer
*/
static void smack_msg_queue_free_security(struct msg_queue *msq)
{
struct kern_ipc_perm *kisp = &msq->q_perm;
kisp->security = NULL;
}
/**
* smack_of_msq - the smack pointer for the msq
* @msq: the object
*
* Returns a pointer to the smack value
*/
static char *smack_of_msq(struct msg_queue *msq)
{
return (char *)msq->q_perm.security;
}
/**
* smk_curacc_msq : helper to check if current has access on msq
* @msq : the msq
* @access : access requested
*
* return 0 if current has access, error otherwise
*/
static int smk_curacc_msq(struct msg_queue *msq, int access)
{
char *msp = smack_of_msq(msq);
struct smk_audit_info ad;
#ifdef CONFIG_AUDIT
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
ad.a.u.ipc_id = msq->q_perm.id;
#endif
return smk_curacc(msp, access, &ad);
}
/**
* smack_msg_queue_associate - Smack access check for msg_queue
* @msq: the object
* @msqflg: access requested
*
* Returns 0 if current has the requested access, error code otherwise
*/
static int smack_msg_queue_associate(struct msg_queue *msq, int msqflg)
{
int may;
may = smack_flags_to_may(msqflg);
return smk_curacc_msq(msq, may);
}
/**
* smack_msg_queue_msgctl - Smack access check for msg_queue
* @msq: the object
* @cmd: what it wants to do
*
* Returns 0 if current has the requested access, error code otherwise
*/
static int smack_msg_queue_msgctl(struct msg_queue *msq, int cmd)
{
int may;
switch (cmd) {
case IPC_STAT:
case MSG_STAT:
may = MAY_READ;
break;
case IPC_SET:
case IPC_RMID:
may = MAY_READWRITE;
break;
case IPC_INFO:
case MSG_INFO:
/*
* System level information
*/
return 0;
default:
return -EINVAL;
}
return smk_curacc_msq(msq, may);
}
/**
* smack_msg_queue_msgsnd - Smack access check for msg_queue
* @msq: the object
* @msg: unused
* @msqflg: access requested
*
* Returns 0 if current has the requested access, error code otherwise
*/
static int smack_msg_queue_msgsnd(struct msg_queue *msq, struct msg_msg *msg,
int msqflg)
{
int may;
may = smack_flags_to_may(msqflg);
return smk_curacc_msq(msq, may);
}
/**
* smack_msg_queue_msgsnd - Smack access check for msg_queue
* @msq: the object
* @msg: unused
* @target: unused
* @type: unused
* @mode: unused
*
* Returns 0 if current has read and write access, error code otherwise
*/
static int smack_msg_queue_msgrcv(struct msg_queue *msq, struct msg_msg *msg,
struct task_struct *target, long type, int mode)
{
return smk_curacc_msq(msq, MAY_READWRITE);
}
/**
* smack_ipc_permission - Smack access for ipc_permission()
* @ipp: the object permissions
* @flag: access requested
*
* Returns 0 if current has read and write access, error code otherwise
*/
static int smack_ipc_permission(struct kern_ipc_perm *ipp, short flag)
{
char *isp = ipp->security;
int may = smack_flags_to_may(flag);
struct smk_audit_info ad;
#ifdef CONFIG_AUDIT
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
ad.a.u.ipc_id = ipp->id;
#endif
return smk_curacc(isp, may, &ad);
}
/**
* smack_ipc_getsecid - Extract smack security id
* @ipp: the object permissions
* @secid: where result will be saved
*/
static void smack_ipc_getsecid(struct kern_ipc_perm *ipp, u32 *secid)
{
char *smack = ipp->security;
*secid = smack_to_secid(smack);
}
/**
* smack_d_instantiate - Make sure the blob is correct on an inode
* @opt_dentry: dentry where inode will be attached
* @inode: the object
*
* Set the inode's security blob if it hasn't been done already.
*/
static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode)
{
struct super_block *sbp;
struct superblock_smack *sbsp;
struct inode_smack *isp;
char *csp = smk_of_current();
char *fetched;
char *final;
char trattr[TRANS_TRUE_SIZE];
int transflag = 0;
struct dentry *dp;
if (inode == NULL)
return;
isp = inode->i_security;
mutex_lock(&isp->smk_lock);
/*
* If the inode is already instantiated
* take the quick way out
*/
if (isp->smk_flags & SMK_INODE_INSTANT)
goto unlockandout;
sbp = inode->i_sb;
sbsp = sbp->s_security;
/*
* We're going to use the superblock default label
* if there's no label on the file.
*/
final = sbsp->smk_default;
/*
* If this is the root inode the superblock
* may be in the process of initialization.
* If that is the case use the root value out
* of the superblock.
*/
if (opt_dentry->d_parent == opt_dentry) {
isp->smk_inode = sbsp->smk_root;
isp->smk_flags |= SMK_INODE_INSTANT;
goto unlockandout;
}
/*
* This is pretty hackish.
* Casey says that we shouldn't have to do
* file system specific code, but it does help
* with keeping it simple.
*/
switch (sbp->s_magic) {
case SMACK_MAGIC:
/*
* Casey says that it's a little embarrassing
* that the smack file system doesn't do
* extended attributes.
*/
final = smack_known_star.smk_known;
break;
case PIPEFS_MAGIC:
/*
* Casey says pipes are easy (?)
*/
final = smack_known_star.smk_known;
break;
case DEVPTS_SUPER_MAGIC:
/*
* devpts seems content with the label of the task.
* Programs that change smack have to treat the
* pty with respect.
*/
final = csp;
break;
case SOCKFS_MAGIC:
/*
* Socket access is controlled by the socket
* structures associated with the task involved.
*/
final = smack_known_star.smk_known;
break;
case PROC_SUPER_MAGIC:
/*
* Casey says procfs appears not to care.
* The superblock default suffices.
*/
break;
case TMPFS_MAGIC:
/*
* Device labels should come from the filesystem,
* but watch out, because they're volitile,
* getting recreated on every reboot.
*/
final = smack_known_star.smk_known;
/*
* No break.
*
* If a smack value has been set we want to use it,
* but since tmpfs isn't giving us the opportunity
* to set mount options simulate setting the
* superblock default.
*/
default:
/*
* This isn't an understood special case.
* Get the value from the xattr.
*/
/*
* UNIX domain sockets use lower level socket data.
*/
if (S_ISSOCK(inode->i_mode)) {
final = smack_known_star.smk_known;
break;
}
/*
* No xattr support means, alas, no SMACK label.
* Use the aforeapplied default.
* It would be curious if the label of the task
* does not match that assigned.
*/
if (inode->i_op->getxattr == NULL)
break;
/*
* Get the dentry for xattr.
*/
dp = dget(opt_dentry);
fetched = smk_fetch(XATTR_NAME_SMACK, inode, dp);
if (fetched != NULL) {
final = fetched;
if (S_ISDIR(inode->i_mode)) {
trattr[0] = '\0';
inode->i_op->getxattr(dp,
XATTR_NAME_SMACKTRANSMUTE,
trattr, TRANS_TRUE_SIZE);
if (strncmp(trattr, TRANS_TRUE,
TRANS_TRUE_SIZE) == 0)
transflag = SMK_INODE_TRANSMUTE;
}
}
isp->smk_task = smk_fetch(XATTR_NAME_SMACKEXEC, inode, dp);
isp->smk_mmap = smk_fetch(XATTR_NAME_SMACKMMAP, inode, dp);
dput(dp);
break;
}
if (final == NULL)
isp->smk_inode = csp;
else
isp->smk_inode = final;
isp->smk_flags |= (SMK_INODE_INSTANT | transflag);
unlockandout:
mutex_unlock(&isp->smk_lock);
return;
}
/**
* smack_getprocattr - Smack process attribute access
* @p: the object task
* @name: the name of the attribute in /proc/.../attr
* @value: where to put the result
*
* Places a copy of the task Smack into value
*
* Returns the length of the smack label or an error code
*/
static int smack_getprocattr(struct task_struct *p, char *name, char **value)
{
char *cp;
int slen;
if (strcmp(name, "current") != 0)
return -EINVAL;
cp = kstrdup(smk_of_task(task_security(p)), GFP_KERNEL);
if (cp == NULL)
return -ENOMEM;
slen = strlen(cp);
*value = cp;
return slen;
}
/**
* smack_setprocattr - Smack process attribute setting
* @p: the object task
* @name: the name of the attribute in /proc/.../attr
* @value: the value to set
* @size: the size of the value
*
* Sets the Smack value of the task. Only setting self
* is permitted and only with privilege
*
* Returns the length of the smack label or an error code
*/
static int smack_setprocattr(struct task_struct *p, char *name,
void *value, size_t size)
{
int rc;
struct task_smack *tsp;
struct task_smack *oldtsp;
struct cred *new;
char *newsmack;
/*
* Changing another process' Smack value is too dangerous
* and supports no sane use case.
*/
if (p != current)
return -EPERM;
if (!capable(CAP_MAC_ADMIN))
return -EPERM;
if (value == NULL || size == 0 || size >= SMK_LABELLEN)
return -EINVAL;
if (strcmp(name, "current") != 0)
return -EINVAL;
newsmack = smk_import(value, size);
if (newsmack == NULL)
return -EINVAL;
/*
* No process is ever allowed the web ("@") label.
*/
if (newsmack == smack_known_web.smk_known)
return -EPERM;
oldtsp = p->cred->security;
new = prepare_creds();
if (new == NULL)
return -ENOMEM;
tsp = new_task_smack(newsmack, oldtsp->smk_forked, GFP_KERNEL);
if (tsp == NULL) {
kfree(new);
return -ENOMEM;
}
rc = smk_copy_rules(&tsp->smk_rules, &oldtsp->smk_rules, GFP_KERNEL);
if (rc != 0)
return rc;
new->security = tsp;
commit_creds(new);
return size;
}
/**
* smack_unix_stream_connect - Smack access on UDS
* @sock: one sock
* @other: the other sock
* @newsk: unused
*
* Return 0 if a subject with the smack of sock could access
* an object with the smack of other, otherwise an error code
*/
static int smack_unix_stream_connect(struct sock *sock,
struct sock *other, struct sock *newsk)
{
struct socket_smack *ssp = sock->sk_security;
struct socket_smack *osp = other->sk_security;
struct socket_smack *nsp = newsk->sk_security;
struct smk_audit_info ad;
int rc = 0;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_NET);
smk_ad_setfield_u_net_sk(&ad, other);
if (!capable(CAP_MAC_OVERRIDE))
rc = smk_access(ssp->smk_out, osp->smk_in, MAY_WRITE, &ad);
/*
* Cross reference the peer labels for SO_PEERSEC.
*/
if (rc == 0) {
nsp->smk_packet = ssp->smk_out;
ssp->smk_packet = osp->smk_out;
}
return rc;
}
/**
* smack_unix_may_send - Smack access on UDS
* @sock: one socket
* @other: the other socket
*
* Return 0 if a subject with the smack of sock could access
* an object with the smack of other, otherwise an error code
*/
static int smack_unix_may_send(struct socket *sock, struct socket *other)
{
struct socket_smack *ssp = sock->sk->sk_security;
struct socket_smack *osp = other->sk->sk_security;
struct smk_audit_info ad;
int rc = 0;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_NET);
smk_ad_setfield_u_net_sk(&ad, other->sk);
if (!capable(CAP_MAC_OVERRIDE))
rc = smk_access(ssp->smk_out, osp->smk_in, MAY_WRITE, &ad);
return rc;
}
/**
* smack_socket_sendmsg - Smack check based on destination host
* @sock: the socket
* @msg: the message
* @size: the size of the message
*
* Return 0 if the current subject can write to the destination
* host. This is only a question if the destination is a single
* label host.
*/
static int smack_socket_sendmsg(struct socket *sock, struct msghdr *msg,
int size)
{
struct sockaddr_in *sip = (struct sockaddr_in *) msg->msg_name;
/*
* Perfectly reasonable for this to be NULL
*/
if (sip == NULL || sip->sin_family != AF_INET)
return 0;
return smack_netlabel_send(sock->sk, sip);
}
/**
* smack_from_secattr - Convert a netlabel attr.mls.lvl/attr.mls.cat pair to smack
* @sap: netlabel secattr
* @ssp: socket security information
*
* Returns a pointer to a Smack label found on the label list.
*/
static char *smack_from_secattr(struct netlbl_lsm_secattr *sap,
struct socket_smack *ssp)
{
struct smack_known *skp;
char smack[SMK_LABELLEN];
char *sp;
int pcat;
if ((sap->flags & NETLBL_SECATTR_MLS_LVL) != 0) {
/*
* Looks like a CIPSO packet.
* If there are flags but no level netlabel isn't
* behaving the way we expect it to.
*
* Get the categories, if any
* Without guidance regarding the smack value
* for the packet fall back on the network
* ambient value.
*/
memset(smack, '\0', SMK_LABELLEN);
if ((sap->flags & NETLBL_SECATTR_MLS_CAT) != 0)
for (pcat = -1;;) {
pcat = netlbl_secattr_catmap_walk(
sap->attr.mls.cat, pcat + 1);
if (pcat < 0)
break;
smack_catset_bit(pcat, smack);
}
/*
* If it is CIPSO using smack direct mapping
* we are already done. WeeHee.
*/
if (sap->attr.mls.lvl == smack_cipso_direct) {
/*
* The label sent is usually on the label list.
*
* If it is not we may still want to allow the
* delivery.
*
* If the recipient is accepting all packets
* because it is using the star ("*") label
* for SMACK64IPIN provide the web ("@") label
* so that a directed response will succeed.
* This is not very correct from a MAC point
* of view, but gets around the problem that
* locking prevents adding the newly discovered
* label to the list.
* The case where the recipient is not using
* the star label should obviously fail.
* The easy way to do this is to provide the
* star label as the subject label.
*/
skp = smk_find_entry(smack);
if (skp != NULL)
return skp->smk_known;
if (ssp != NULL &&
ssp->smk_in == smack_known_star.smk_known)
return smack_known_web.smk_known;
return smack_known_star.smk_known;
}
/*
* Look it up in the supplied table if it is not
* a direct mapping.
*/
sp = smack_from_cipso(sap->attr.mls.lvl, smack);
if (sp != NULL)
return sp;
if (ssp != NULL && ssp->smk_in == smack_known_star.smk_known)
return smack_known_web.smk_known;
return smack_known_star.smk_known;
}
if ((sap->flags & NETLBL_SECATTR_SECID) != 0) {
/*
* Looks like a fallback, which gives us a secid.
*/
sp = smack_from_secid(sap->attr.secid);
/*
* This has got to be a bug because it is
* impossible to specify a fallback without
* specifying the label, which will ensure
* it has a secid, and the only way to get a
* secid is from a fallback.
*/
BUG_ON(sp == NULL);
return sp;
}
/*
* Without guidance regarding the smack value
* for the packet fall back on the network
* ambient value.
*/
return smack_net_ambient;
}
/**
* smack_socket_sock_rcv_skb - Smack packet delivery access check
* @sk: socket
* @skb: packet
*
* Returns 0 if the packet should be delivered, an error code otherwise
*/
static int smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
struct netlbl_lsm_secattr secattr;
struct socket_smack *ssp = sk->sk_security;
char *csp;
int rc;
struct smk_audit_info ad;
if (sk->sk_family != PF_INET && sk->sk_family != PF_INET6)
return 0;
/*
* Translate what netlabel gave us.
*/
netlbl_secattr_init(&secattr);
rc = netlbl_skbuff_getattr(skb, sk->sk_family, &secattr);
if (rc == 0)
csp = smack_from_secattr(&secattr, ssp);
else
csp = smack_net_ambient;
netlbl_secattr_destroy(&secattr);
#ifdef CONFIG_AUDIT
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_NET);
ad.a.u.net.family = sk->sk_family;
ad.a.u.net.netif = skb->skb_iif;
ipv4_skb_to_auditdata(skb, &ad.a, NULL);
#endif
/*
* Receiving a packet requires that the other end
* be able to write here. Read access is not required.
* This is the simplist possible security model
* for networking.
*/
rc = smk_access(csp, ssp->smk_in, MAY_WRITE, &ad);
if (rc != 0)
netlbl_skbuff_err(skb, rc, 0);
return rc;
}
/**
* smack_socket_getpeersec_stream - pull in packet label
* @sock: the socket
* @optval: user's destination
* @optlen: size thereof
* @len: max thereof
*
* returns zero on success, an error code otherwise
*/
static int smack_socket_getpeersec_stream(struct socket *sock,
char __user *optval,
int __user *optlen, unsigned len)
{
struct socket_smack *ssp;
char *rcp = "";
int slen = 1;
int rc = 0;
ssp = sock->sk->sk_security;
if (ssp->smk_packet != NULL) {
rcp = ssp->smk_packet;
slen = strlen(rcp) + 1;
}
if (slen > len)
rc = -ERANGE;
else if (copy_to_user(optval, rcp, slen) != 0)
rc = -EFAULT;
if (put_user(slen, optlen) != 0)
rc = -EFAULT;
return rc;
}
/**
* smack_socket_getpeersec_dgram - pull in packet label
* @sock: the peer socket
* @skb: packet data
* @secid: pointer to where to put the secid of the packet
*
* Sets the netlabel socket state on sk from parent
*/
static int smack_socket_getpeersec_dgram(struct socket *sock,
struct sk_buff *skb, u32 *secid)
{
struct netlbl_lsm_secattr secattr;
struct socket_smack *ssp = NULL;
char *sp;
int family = PF_UNSPEC;
u32 s = 0; /* 0 is the invalid secid */
int rc;
if (skb != NULL) {
if (skb->protocol == htons(ETH_P_IP))
family = PF_INET;
else if (skb->protocol == htons(ETH_P_IPV6))
family = PF_INET6;
}
if (family == PF_UNSPEC && sock != NULL)
family = sock->sk->sk_family;
if (family == PF_UNIX) {
ssp = sock->sk->sk_security;
s = smack_to_secid(ssp->smk_out);
} else if (family == PF_INET || family == PF_INET6) {
/*
* Translate what netlabel gave us.
*/
if (sock != NULL && sock->sk != NULL)
ssp = sock->sk->sk_security;
netlbl_secattr_init(&secattr);
rc = netlbl_skbuff_getattr(skb, family, &secattr);
if (rc == 0) {
sp = smack_from_secattr(&secattr, ssp);
s = smack_to_secid(sp);
}
netlbl_secattr_destroy(&secattr);
}
*secid = s;
if (s == 0)
return -EINVAL;
return 0;
}
/**
* smack_sock_graft - Initialize a newly created socket with an existing sock
* @sk: child sock
* @parent: parent socket
*
* Set the smk_{in,out} state of an existing sock based on the process that
* is creating the new socket.
*/
static void smack_sock_graft(struct sock *sk, struct socket *parent)
{
struct socket_smack *ssp;
if (sk == NULL ||
(sk->sk_family != PF_INET && sk->sk_family != PF_INET6))
return;
ssp = sk->sk_security;
ssp->smk_in = ssp->smk_out = smk_of_current();
/* cssp->smk_packet is already set in smack_inet_csk_clone() */
}
/**
* smack_inet_conn_request - Smack access check on connect
* @sk: socket involved
* @skb: packet
* @req: unused
*
* Returns 0 if a task with the packet label could write to
* the socket, otherwise an error code
*/
static int smack_inet_conn_request(struct sock *sk, struct sk_buff *skb,
struct request_sock *req)
{
u16 family = sk->sk_family;
struct socket_smack *ssp = sk->sk_security;
struct netlbl_lsm_secattr secattr;
struct sockaddr_in addr;
struct iphdr *hdr;
char *sp;
int rc;
struct smk_audit_info ad;
/* handle mapped IPv4 packets arriving via IPv6 sockets */
if (family == PF_INET6 && skb->protocol == htons(ETH_P_IP))
family = PF_INET;
netlbl_secattr_init(&secattr);
rc = netlbl_skbuff_getattr(skb, family, &secattr);
if (rc == 0)
sp = smack_from_secattr(&secattr, ssp);
else
sp = smack_known_huh.smk_known;
netlbl_secattr_destroy(&secattr);
#ifdef CONFIG_AUDIT
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_NET);
ad.a.u.net.family = family;
ad.a.u.net.netif = skb->skb_iif;
ipv4_skb_to_auditdata(skb, &ad.a, NULL);
#endif
/*
* Receiving a packet requires that the other end be able to write
* here. Read access is not required.
*/
rc = smk_access(sp, ssp->smk_in, MAY_WRITE, &ad);
if (rc != 0)
return rc;
/*
* Save the peer's label in the request_sock so we can later setup
* smk_packet in the child socket so that SO_PEERCRED can report it.
*/
req->peer_secid = smack_to_secid(sp);
/*
* We need to decide if we want to label the incoming connection here
* if we do we only need to label the request_sock and the stack will
* propagate the wire-label to the sock when it is created.
*/
hdr = ip_hdr(skb);
addr.sin_addr.s_addr = hdr->saddr;
rcu_read_lock();
if (smack_host_label(&addr) == NULL) {
rcu_read_unlock();
netlbl_secattr_init(&secattr);
smack_to_secattr(sp, &secattr);
rc = netlbl_req_setattr(req, &secattr);
netlbl_secattr_destroy(&secattr);
} else {
rcu_read_unlock();
netlbl_req_delattr(req);
}
return rc;
}
/**
* smack_inet_csk_clone - Copy the connection information to the new socket
* @sk: the new socket
* @req: the connection's request_sock
*
* Transfer the connection's peer label to the newly created socket.
*/
static void smack_inet_csk_clone(struct sock *sk,
const struct request_sock *req)
{
struct socket_smack *ssp = sk->sk_security;
if (req->peer_secid != 0)
ssp->smk_packet = smack_from_secid(req->peer_secid);
else
ssp->smk_packet = NULL;
}
/*
* Key management security hooks
*
* Casey has not tested key support very heavily.
* The permission check is most likely too restrictive.
* If you care about keys please have a look.
*/
#ifdef CONFIG_KEYS
/**
* smack_key_alloc - Set the key security blob
* @key: object
* @cred: the credentials to use
* @flags: unused
*
* No allocation required
*
* Returns 0
*/
static int smack_key_alloc(struct key *key, const struct cred *cred,
unsigned long flags)
{
key->security = smk_of_task(cred->security);
return 0;
}
/**
* smack_key_free - Clear the key security blob
* @key: the object
*
* Clear the blob pointer
*/
static void smack_key_free(struct key *key)
{
key->security = NULL;
}
/*
* smack_key_permission - Smack access on a key
* @key_ref: gets to the object
* @cred: the credentials to use
* @perm: unused
*
* Return 0 if the task has read and write to the object,
* an error code otherwise
*/
static int smack_key_permission(key_ref_t key_ref,
const struct cred *cred, key_perm_t perm)
{
struct key *keyp;
struct smk_audit_info ad;
char *tsp = smk_of_task(cred->security);
keyp = key_ref_to_ptr(key_ref);
if (keyp == NULL)
return -EINVAL;
/*
* If the key hasn't been initialized give it access so that
* it may do so.
*/
if (keyp->security == NULL)
return 0;
/*
* This should not occur
*/
if (tsp == NULL)
return -EACCES;
#ifdef CONFIG_AUDIT
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_KEY);
ad.a.u.key_struct.key = keyp->serial;
ad.a.u.key_struct.key_desc = keyp->description;
#endif
return smk_access(tsp, keyp->security,
MAY_READWRITE, &ad);
}
#endif /* CONFIG_KEYS */
/*
* Smack Audit hooks
*
* Audit requires a unique representation of each Smack specific
* rule. This unique representation is used to distinguish the
* object to be audited from remaining kernel objects and also
* works as a glue between the audit hooks.
*
* Since repository entries are added but never deleted, we'll use
* the smack_known label address related to the given audit rule as
* the needed unique representation. This also better fits the smack
* model where nearly everything is a label.
*/
#ifdef CONFIG_AUDIT
/**
* smack_audit_rule_init - Initialize a smack audit rule
* @field: audit rule fields given from user-space (audit.h)
* @op: required testing operator (=, !=, >, <, ...)
* @rulestr: smack label to be audited
* @vrule: pointer to save our own audit rule representation
*
* Prepare to audit cases where (@field @op @rulestr) is true.
* The label to be audited is created if necessay.
*/
static int smack_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule)
{
char **rule = (char **)vrule;
*rule = NULL;
if (field != AUDIT_SUBJ_USER && field != AUDIT_OBJ_USER)
return -EINVAL;
if (op != Audit_equal && op != Audit_not_equal)
return -EINVAL;
*rule = smk_import(rulestr, 0);
return 0;
}
/**
* smack_audit_rule_known - Distinguish Smack audit rules
* @krule: rule of interest, in Audit kernel representation format
*
* This is used to filter Smack rules from remaining Audit ones.
* If it's proved that this rule belongs to us, the
* audit_rule_match hook will be called to do the final judgement.
*/
static int smack_audit_rule_known(struct audit_krule *krule)
{
struct audit_field *f;
int i;
for (i = 0; i < krule->field_count; i++) {
f = &krule->fields[i];
if (f->type == AUDIT_SUBJ_USER || f->type == AUDIT_OBJ_USER)
return 1;
}
return 0;
}
/**
* smack_audit_rule_match - Audit given object ?
* @secid: security id for identifying the object to test
* @field: audit rule flags given from user-space
* @op: required testing operator
* @vrule: smack internal rule presentation
* @actx: audit context associated with the check
*
* The core Audit hook. It's used to take the decision of
* whether to audit or not to audit a given object.
*/
static int smack_audit_rule_match(u32 secid, u32 field, u32 op, void *vrule,
struct audit_context *actx)
{
char *smack;
char *rule = vrule;
if (!rule) {
audit_log(actx, GFP_KERNEL, AUDIT_SELINUX_ERR,
"Smack: missing rule\n");
return -ENOENT;
}
if (field != AUDIT_SUBJ_USER && field != AUDIT_OBJ_USER)
return 0;
smack = smack_from_secid(secid);
/*
* No need to do string comparisons. If a match occurs,
* both pointers will point to the same smack_known
* label.
*/
if (op == Audit_equal)
return (rule == smack);
if (op == Audit_not_equal)
return (rule != smack);
return 0;
}
/**
* smack_audit_rule_free - free smack rule representation
* @vrule: rule to be freed.
*
* No memory was allocated.
*/
static void smack_audit_rule_free(void *vrule)
{
/* No-op */
}
#endif /* CONFIG_AUDIT */
/**
* smack_secid_to_secctx - return the smack label for a secid
* @secid: incoming integer
* @secdata: destination
* @seclen: how long it is
*
* Exists for networking code.
*/
static int smack_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
{
char *sp = smack_from_secid(secid);
if (secdata)
*secdata = sp;
*seclen = strlen(sp);
return 0;
}
/**
* smack_secctx_to_secid - return the secid for a smack label
* @secdata: smack label
* @seclen: how long result is
* @secid: outgoing integer
*
* Exists for audit and networking code.
*/
static int smack_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)
{
*secid = smack_to_secid(secdata);
return 0;
}
/**
* smack_release_secctx - don't do anything.
* @secdata: unused
* @seclen: unused
*
* Exists to make sure nothing gets done, and properly
*/
static void smack_release_secctx(char *secdata, u32 seclen)
{
}
static int smack_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen)
{
return smack_inode_setsecurity(inode, XATTR_SMACK_SUFFIX, ctx, ctxlen, 0);
}
static int smack_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen)
{
return __vfs_setxattr_noperm(dentry, XATTR_NAME_SMACK, ctx, ctxlen, 0);
}
static int smack_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)
{
int len = 0;
len = smack_inode_getsecurity(inode, XATTR_SMACK_SUFFIX, ctx, true);
if (len < 0)
return len;
*ctxlen = len;
return 0;
}
struct security_operations smack_ops = {
.name = "smack",
.ptrace_access_check = smack_ptrace_access_check,
.ptrace_traceme = smack_ptrace_traceme,
.syslog = smack_syslog,
.sb_alloc_security = smack_sb_alloc_security,
.sb_free_security = smack_sb_free_security,
.sb_copy_data = smack_sb_copy_data,
.sb_kern_mount = smack_sb_kern_mount,
.sb_statfs = smack_sb_statfs,
.sb_mount = smack_sb_mount,
.sb_umount = smack_sb_umount,
.bprm_set_creds = smack_bprm_set_creds,
.bprm_committing_creds = smack_bprm_committing_creds,
.bprm_secureexec = smack_bprm_secureexec,
.inode_alloc_security = smack_inode_alloc_security,
.inode_free_security = smack_inode_free_security,
.inode_init_security = smack_inode_init_security,
.inode_link = smack_inode_link,
.inode_unlink = smack_inode_unlink,
.inode_rmdir = smack_inode_rmdir,
.inode_rename = smack_inode_rename,
.inode_permission = smack_inode_permission,
.inode_setattr = smack_inode_setattr,
.inode_getattr = smack_inode_getattr,
.inode_setxattr = smack_inode_setxattr,
.inode_post_setxattr = smack_inode_post_setxattr,
.inode_getxattr = smack_inode_getxattr,
.inode_removexattr = smack_inode_removexattr,
.inode_getsecurity = smack_inode_getsecurity,
.inode_setsecurity = smack_inode_setsecurity,
.inode_listsecurity = smack_inode_listsecurity,
.inode_getsecid = smack_inode_getsecid,
.file_permission = smack_file_permission,
.file_alloc_security = smack_file_alloc_security,
.file_free_security = smack_file_free_security,
.file_ioctl = smack_file_ioctl,
.file_lock = smack_file_lock,
.file_fcntl = smack_file_fcntl,
.file_mmap = smack_file_mmap,
.file_set_fowner = smack_file_set_fowner,
.file_send_sigiotask = smack_file_send_sigiotask,
.file_receive = smack_file_receive,
.dentry_open = smack_dentry_open,
.cred_alloc_blank = smack_cred_alloc_blank,
.cred_free = smack_cred_free,
.cred_prepare = smack_cred_prepare,
.cred_transfer = smack_cred_transfer,
.kernel_act_as = smack_kernel_act_as,
.kernel_create_files_as = smack_kernel_create_files_as,
.task_setpgid = smack_task_setpgid,
.task_getpgid = smack_task_getpgid,
.task_getsid = smack_task_getsid,
.task_getsecid = smack_task_getsecid,
.task_setnice = smack_task_setnice,
.task_setioprio = smack_task_setioprio,
.task_getioprio = smack_task_getioprio,
.task_setscheduler = smack_task_setscheduler,
.task_getscheduler = smack_task_getscheduler,
.task_movememory = smack_task_movememory,
.task_kill = smack_task_kill,
.task_wait = smack_task_wait,
.task_to_inode = smack_task_to_inode,
.ipc_permission = smack_ipc_permission,
.ipc_getsecid = smack_ipc_getsecid,
.msg_msg_alloc_security = smack_msg_msg_alloc_security,
.msg_msg_free_security = smack_msg_msg_free_security,
.msg_queue_alloc_security = smack_msg_queue_alloc_security,
.msg_queue_free_security = smack_msg_queue_free_security,
.msg_queue_associate = smack_msg_queue_associate,
.msg_queue_msgctl = smack_msg_queue_msgctl,
.msg_queue_msgsnd = smack_msg_queue_msgsnd,
.msg_queue_msgrcv = smack_msg_queue_msgrcv,
.shm_alloc_security = smack_shm_alloc_security,
.shm_free_security = smack_shm_free_security,
.shm_associate = smack_shm_associate,
.shm_shmctl = smack_shm_shmctl,
.shm_shmat = smack_shm_shmat,
.sem_alloc_security = smack_sem_alloc_security,
.sem_free_security = smack_sem_free_security,
.sem_associate = smack_sem_associate,
.sem_semctl = smack_sem_semctl,
.sem_semop = smack_sem_semop,
.d_instantiate = smack_d_instantiate,
.getprocattr = smack_getprocattr,
.setprocattr = smack_setprocattr,
.unix_stream_connect = smack_unix_stream_connect,
.unix_may_send = smack_unix_may_send,
.socket_post_create = smack_socket_post_create,
.socket_connect = smack_socket_connect,
.socket_sendmsg = smack_socket_sendmsg,
.socket_sock_rcv_skb = smack_socket_sock_rcv_skb,
.socket_getpeersec_stream = smack_socket_getpeersec_stream,
.socket_getpeersec_dgram = smack_socket_getpeersec_dgram,
.sk_alloc_security = smack_sk_alloc_security,
.sk_free_security = smack_sk_free_security,
.sock_graft = smack_sock_graft,
.inet_conn_request = smack_inet_conn_request,
.inet_csk_clone = smack_inet_csk_clone,
/* key management security hooks */
#ifdef CONFIG_KEYS
.key_alloc = smack_key_alloc,
.key_free = smack_key_free,
.key_permission = smack_key_permission,
#endif /* CONFIG_KEYS */
/* Audit hooks */
#ifdef CONFIG_AUDIT
.audit_rule_init = smack_audit_rule_init,
.audit_rule_known = smack_audit_rule_known,
.audit_rule_match = smack_audit_rule_match,
.audit_rule_free = smack_audit_rule_free,
#endif /* CONFIG_AUDIT */
.secid_to_secctx = smack_secid_to_secctx,
.secctx_to_secid = smack_secctx_to_secid,
.release_secctx = smack_release_secctx,
.inode_notifysecctx = smack_inode_notifysecctx,
.inode_setsecctx = smack_inode_setsecctx,
.inode_getsecctx = smack_inode_getsecctx,
};
static __init void init_smack_know_list(void)
{
list_add(&smack_known_huh.list, &smack_known_list);
list_add(&smack_known_hat.list, &smack_known_list);
list_add(&smack_known_star.list, &smack_known_list);
list_add(&smack_known_floor.list, &smack_known_list);
list_add(&smack_known_invalid.list, &smack_known_list);
list_add(&smack_known_web.list, &smack_known_list);
}
/**
* smack_init - initialize the smack system
*
* Returns 0
*/
static __init int smack_init(void)
{
struct cred *cred;
struct task_smack *tsp;
if (!security_module_enable(&smack_ops))
return 0;
tsp = new_task_smack(smack_known_floor.smk_known,
smack_known_floor.smk_known, GFP_KERNEL);
if (tsp == NULL)
return -ENOMEM;
printk(KERN_INFO "Smack: Initializing.\n");
/*
* Set the security state for the initial task.
*/
cred = (struct cred *) current->cred;
cred->security = tsp;
/* initialize the smack_know_list */
init_smack_know_list();
/*
* Initialize locks
*/
spin_lock_init(&smack_known_huh.smk_cipsolock);
spin_lock_init(&smack_known_hat.smk_cipsolock);
spin_lock_init(&smack_known_star.smk_cipsolock);
spin_lock_init(&smack_known_floor.smk_cipsolock);
spin_lock_init(&smack_known_invalid.smk_cipsolock);
/*
* Register with LSM
*/
if (register_security(&smack_ops))
panic("smack: Unable to register with kernel.\n");
return 0;
}
/*
* Smack requires early initialization in order to label
* all processes and objects when they are created.
*/
security_initcall(smack_init);
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