This patch adds support for checking environment variable's names. Although TOMOYO already provides ability to check argv[]/envp[] passed to execve() requests, file execute /bin/sh exec.envp["LD_LIBRARY_PATH"]="bar" will reject execution of /bin/sh if environment variable LD_LIBRARY_PATH is not defined. To grant execution of /bin/sh if LD_LIBRARY_PATH is not defined, administrators have to specify like file execute /bin/sh exec.envp["LD_LIBRARY_PATH"]="/system/lib" file execute /bin/sh exec.envp["LD_LIBRARY_PATH"]=NULL . Since there are many environment variables whereas conditional checks are applied as "&&", it is difficult to cover all combinations. Therefore, this patch supports conditional checks that are applied as "||", by specifying like file execute /bin/sh misc env LD_LIBRARY_PATH exec.envp["LD_LIBRARY_PATH"]="/system/lib" which means "grant execution of /bin/sh if environment variable is not defined or is defined and its value is /system/lib". Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: James Morris <jmorris@namei.org>
		
			
				
	
	
		
			122 lines
		
	
	
	
		
			3 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			122 lines
		
	
	
	
		
			3 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * security/tomoyo/environ.c
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 *
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 * Copyright (C) 2005-2011  NTT DATA CORPORATION
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 */
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#include "common.h"
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/**
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 * tomoyo_check_env_acl - Check permission for environment variable's name.
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 *
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 * @r:   Pointer to "struct tomoyo_request_info".
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 * @ptr: Pointer to "struct tomoyo_acl_info".
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 *
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 * Returns true if granted, false otherwise.
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 */
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static bool tomoyo_check_env_acl(struct tomoyo_request_info *r,
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				 const struct tomoyo_acl_info *ptr)
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{
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	const struct tomoyo_env_acl *acl =
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		container_of(ptr, typeof(*acl), head);
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	return tomoyo_path_matches_pattern(r->param.environ.name, acl->env);
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}
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/**
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 * tomoyo_audit_env_log - Audit environment variable name log.
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 *
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 * @r: Pointer to "struct tomoyo_request_info".
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 *
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 * Returns 0 on success, negative value otherwise.
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 */
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static int tomoyo_audit_env_log(struct tomoyo_request_info *r)
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{
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	return tomoyo_supervisor(r, "misc env %s\n",
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				 r->param.environ.name->name);
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}
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/**
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 * tomoyo_env_perm - Check permission for environment variable's name.
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 *
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 * @r:   Pointer to "struct tomoyo_request_info".
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 * @env: The name of environment variable.
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 *
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 * Returns 0 on success, negative value otherwise.
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 *
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 * Caller holds tomoyo_read_lock().
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 */
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int tomoyo_env_perm(struct tomoyo_request_info *r, const char *env)
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{
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	struct tomoyo_path_info environ;
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	int error;
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	if (!env || !*env)
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		return 0;
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	environ.name = env;
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	tomoyo_fill_path_info(&environ);
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	r->param_type = TOMOYO_TYPE_ENV_ACL;
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	r->param.environ.name = &environ;
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	do {
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		tomoyo_check_acl(r, tomoyo_check_env_acl);
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		error = tomoyo_audit_env_log(r);
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	} while (error == TOMOYO_RETRY_REQUEST);
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	return error;
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}
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/**
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 * tomoyo_same_env_acl - Check for duplicated "struct tomoyo_env_acl" entry.
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 *
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 * @a: Pointer to "struct tomoyo_acl_info".
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 * @b: Pointer to "struct tomoyo_acl_info".
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 *
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 * Returns true if @a == @b, false otherwise.
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 */
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static bool tomoyo_same_env_acl(const struct tomoyo_acl_info *a,
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				const struct tomoyo_acl_info *b)
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{
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	const struct tomoyo_env_acl *p1 = container_of(a, typeof(*p1), head);
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	const struct tomoyo_env_acl *p2 = container_of(b, typeof(*p2), head);
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	return p1->env == p2->env;
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}
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/**
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 * tomoyo_write_env - Write "struct tomoyo_env_acl" list.
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 *
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 * @param: Pointer to "struct tomoyo_acl_param".
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 *
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 * Returns 0 on success, negative value otherwise.
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 *
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 * Caller holds tomoyo_read_lock().
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 */
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static int tomoyo_write_env(struct tomoyo_acl_param *param)
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{
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	struct tomoyo_env_acl e = { .head.type = TOMOYO_TYPE_ENV_ACL };
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	int error = -ENOMEM;
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	const char *data = tomoyo_read_token(param);
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	if (!tomoyo_correct_word(data) || strchr(data, '='))
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		return -EINVAL;
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	e.env = tomoyo_get_name(data);
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	if (!e.env)
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		return error;
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	error = tomoyo_update_domain(&e.head, sizeof(e), param,
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				  tomoyo_same_env_acl, NULL);
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	tomoyo_put_name(e.env);
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	return error;
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}
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/**
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 * tomoyo_write_misc - Update environment variable list.
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 *
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 * @param: Pointer to "struct tomoyo_acl_param".
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 *
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 * Returns 0 on success, negative value otherwise.
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 */
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int tomoyo_write_misc(struct tomoyo_acl_param *param)
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{
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	if (tomoyo_str_starts(¶m->data, "env "))
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		return tomoyo_write_env(param);
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	return -EINVAL;
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}
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