Revert "exec: avoid RLIMIT_STACK races with prlimit()"

This reverts commit 04e35f4495.

SELinux runs with secureexec for all non-"noatsecure" domain transitions,
which means lots of processes end up hitting the stack hard-limit change
that was introduced in order to fix a race with prlimit(). That race fix
will need to be redesigned.

Reported-by: Laura Abbott <labbott@redhat.com>
Reported-by: Tomáš Trnka <trnka@scm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Kees Cook 2017-12-12 11:28:38 -08:00 committed by Linus Torvalds
parent f8940a0f20
commit 779f4e1c6c

View File

@ -1339,15 +1339,10 @@ void setup_new_exec(struct linux_binprm * bprm)
* avoid bad behavior from the prior rlimits. This has to * avoid bad behavior from the prior rlimits. This has to
* happen before arch_pick_mmap_layout(), which examines * happen before arch_pick_mmap_layout(), which examines
* RLIMIT_STACK, but after the point of no return to avoid * RLIMIT_STACK, but after the point of no return to avoid
* races from other threads changing the limits. This also * needing to clean up the change on failure.
* must be protected from races with prlimit() calls.
*/ */
task_lock(current->group_leader);
if (current->signal->rlim[RLIMIT_STACK].rlim_cur > _STK_LIM) if (current->signal->rlim[RLIMIT_STACK].rlim_cur > _STK_LIM)
current->signal->rlim[RLIMIT_STACK].rlim_cur = _STK_LIM; current->signal->rlim[RLIMIT_STACK].rlim_cur = _STK_LIM;
if (current->signal->rlim[RLIMIT_STACK].rlim_max > _STK_LIM)
current->signal->rlim[RLIMIT_STACK].rlim_max = _STK_LIM;
task_unlock(current->group_leader);
} }
arch_pick_mmap_layout(current->mm); arch_pick_mmap_layout(current->mm);