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

This reverts commit 04e35f4495dd560db30c25efca4eecae8ec8c375.

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>

1 files changed, 1 insertions, 6 deletions

diff --git a/fs/exec.c b/fs/exec.c
index 156f56acfe8e..5688b5e1b937 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1339,15 +1339,10 @@ void setup_new_exec(struct linux_binprm * bprm)
                  * avoid bad behavior from the prior rlimits. This has to
                  * happen before arch_pick_mmap_layout(), which examines
                  * RLIMIT_STACK, but after the point of no return to avoid
-                 * races from other threads changing the limits. This also
-                 * must be protected from races with prlimit() calls.
+                 * needing to clean up the change on failure.
                  */
-                task_lock(current->group_leader);
                 if (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);