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author | Dhaval Giani <dhaval@linux.vnet.ibm.com> | 2009-02-27 15:13:54 +0530 |
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committer | Ingo Molnar <mingo@elte.hu> | 2009-02-27 11:11:53 +0100 |
commit | 54e991242850edc8c53f71fa5aa3ba7a93ce38f5 (patch) | |
tree | 7f136214aab690a8ee4a294ca9c1a7e01de0dc49 /kernel/user.c | |
parent | cac64d00c256e65776d575e82aaf540632b66178 (diff) | |
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sched: don't allow setuid to succeed if the user does not have rt bandwidth
Impact: fix hung task with certain (non-default) rt-limit settings
Corey Hickey reported that on using setuid to change the uid of a
rt process, the process would be unkillable and not be running.
This is because there was no rt runtime for that user group. Add
in a check to see if a user can attach an rt task to its task group.
On failure, return EINVAL, which is also returned in
CONFIG_CGROUP_SCHED.
Reported-by: Corey Hickey <bugfood-ml@fatooh.org>
Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/user.c')
-rw-r--r-- | kernel/user.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/kernel/user.c b/kernel/user.c index 3551ac7..6a9b696 100644 --- a/kernel/user.c +++ b/kernel/user.c @@ -362,6 +362,24 @@ static void free_user(struct user_struct *up, unsigned long flags) #endif +#if defined(CONFIG_RT_GROUP_SCHED) && defined(CONFIG_USER_SCHED) +/* + * We need to check if a setuid can take place. This function should be called + * before successfully completing the setuid. + */ +int task_can_switch_user(struct user_struct *up, struct task_struct *tsk) +{ + + return sched_rt_can_attach(up->tg, tsk); + +} +#else +int task_can_switch_user(struct user_struct *up, struct task_struct *tsk) +{ + return 1; +} +#endif + /* * Locate the user_struct for the passed UID. If found, take a ref on it. The * caller must undo that ref with free_uid(). |