Messages in this thread Patch in this message | | | From | Jiri Slaby <> | Subject | [PATCH v4 07/12] rlimits: do security check under task_lock | Date | Wed, 23 Jun 2010 23:52:08 +0200 |
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Do security_task_setrlimit under task_lock. Other tasks may change limits under our hands while we are checking limits inside the function. From now on, they can't.
Note that all the security work is done under a spinlock here now. Security hooks count with that, they are called from interrupt context (like security_task_kill) and with spinlocks already held (e.g. capable->security_capable).
Signed-off-by: Jiri Slaby <jslaby@suse.cz> Acked-by: James Morris <jmorris@namei.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> --- kernel/sys.c | 20 ++++++++++---------- 1 files changed, 10 insertions(+), 10 deletions(-)
diff --git a/kernel/sys.c b/kernel/sys.c index 9dbcbbc..c762eeb 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1277,7 +1277,7 @@ int do_setrlimit(struct task_struct *tsk, unsigned int resource, struct rlimit *new_rlim) { struct rlimit *old_rlim; - int retval; + int retval = 0; if (resource >= RLIM_NLIMITS) return -EINVAL; @@ -1293,9 +1293,14 @@ int do_setrlimit(struct task_struct *tsk, unsigned int resource, goto out; } - retval = security_task_setrlimit(tsk->group_leader, resource, new_rlim); - if (retval) - goto out; + old_rlim = tsk->signal->rlim + resource; + task_lock(tsk->group_leader); + if (new_rlim->rlim_max > old_rlim->rlim_max && + !capable(CAP_SYS_RESOURCE)) + retval = -EPERM; + if (!retval) + retval = security_task_setrlimit(tsk->group_leader, resource, + new_rlim); if (resource == RLIMIT_CPU && new_rlim->rlim_cur == 0) { /* @@ -1307,12 +1312,7 @@ int do_setrlimit(struct task_struct *tsk, unsigned int resource, new_rlim->rlim_cur = 1; } - old_rlim = tsk->signal->rlim + resource; - task_lock(tsk->group_leader); - if (new_rlim->rlim_max > old_rlim->rlim_max && - !capable(CAP_SYS_RESOURCE)) - retval = -EPERM; - else + if (!retval) *old_rlim = *new_rlim; task_unlock(tsk->group_leader); -- 1.7.1
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