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user namespace: usb: make usb urbs user namespace aware (v2)

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Add to the dev_state and alloc_async structures the user namespace
corresponding to the uid and euid.  Pass these to kill_pid_info_as_uid(),
which can then implement a proper, user-namespace-aware uid check.

Changelog:
Sep 20: Per Oleg's suggestion: Instead of caching and passing user namespace,
	uid, and euid each separately, pass a struct cred.
Sep 26: Address Alan Stern's comments: don't define a struct cred at
	usbdev_open(), and take and put a cred at async_completed() to
	ensure it lasts for the duration of kill_pid_info_as_cred().

Signed-off-by: Serge Hallyn <serge.hallyn@canonical.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Serge Hallyn 2011-09-26 10:45:18 -05:00 • committed by Greg Kroah-Hartman
parent edb2b255a0
commit d178bc3a70
3 changed files with 31 additions and 26 deletions
Download patch file Download diff file Expand all files Collapse all files

24
kernel/signal.c
View file

@ -1344,13 +1344,24 @@ int kill_proc_info(int sig, struct siginfo *info, pid_t pid)
return error;
}
static int kill_as_cred_perm(const struct cred *cred,
struct task_struct *target)
{
const struct cred *pcred = __task_cred(target);
if (cred->user_ns != pcred->user_ns)
return 0;
if (cred->euid != pcred->suid && cred->euid != pcred->uid &&
cred->uid != pcred->suid && cred->uid != pcred->uid)
return 0;
return 1;
}
/* like kill_pid_info(), but doesn't use uid/euid of "current" */
int kill_pid_info_as_uid(int sig, struct siginfo *info, struct pid *pid,
uid_t uid, uid_t euid, u32 secid)
int kill_pid_info_as_cred(int sig, struct siginfo *info, struct pid *pid,
const struct cred *cred, u32 secid)
{
int ret = -EINVAL;
struct task_struct *p;
const struct cred *pcred;
unsigned long flags;
if (!valid_signal(sig))
@ -1362,10 +1373,7 @@ int kill_pid_info_as_uid(int sig, struct siginfo *info, struct pid *pid,
ret = -ESRCH;
goto out_unlock;
}
pcred = __task_cred(p);
if (si_fromuser(info) &&
euid != pcred->suid && euid != pcred->uid &&
uid != pcred->suid && uid != pcred->uid) {
if (si_fromuser(info) && !kill_as_cred_perm(cred, p)) {
ret = -EPERM;
goto out_unlock;
}
@ -1384,7 +1392,7 @@ out_unlock:
rcu_read_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(kill_pid_info_as_uid);
EXPORT_SYMBOL_GPL(kill_pid_info_as_cred);
/*
* kill_something_info() interprets pid in interesting ways just like kill(2).