Please pull this fix for a regression in the seccomp code (it was supposed
to be in the first pull req but I had it queued in the wrong branch).
The following changes since commit 37c85961c3f87f2141c84e53df31e59db072fd2e:
Merge tag 'tty-4.11-rc1' of
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty (2017-02-22 12:17:25
-0800)
are available in the git repository at:
git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security.git
for-linus
Kees Cook (1):
seccomp: Only dump core when single-threaded
kernel/seccomp.c | 13 ++++++++-----
1 files changed, 8 insertions(+), 5 deletions(-)
---
commit d7276e321ff8a53106a59c85ca46d03e34288893
Author: Kees Cook <[email protected]>
Date: Tue Feb 7 15:18:51 2017 -0800
seccomp: Only dump core when single-threaded
The SECCOMP_RET_KILL filter return code has always killed the current
thread, not the entire process. Changing this as a side-effect of dumping
core isn't a safe thing to do (a few test suites have already flagged this
behavioral change). Instead, restore the RET_KILL semantics, but still
dump core when a RET_KILL delivers SIGSYS to a single-threaded process.
Fixes: b25e67161c29 ("seccomp: dump core when using SECCOMP_RET_KILL")
Signed-off-by: Kees Cook <[email protected]>
Acked-by: Andrei Vagin <[email protected]>
Signed-off-by: James Morris <[email protected]>
diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index f8f88eb..e15185c 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -643,11 +643,14 @@ static int __seccomp_filter(int this_syscall, const
struct seccomp_data *sd,
default: {
siginfo_t info;
audit_seccomp(this_syscall, SIGSYS, action);
- /* Show the original registers in the dump. */
- syscall_rollback(current, task_pt_regs(current));
- /* Trigger a manual coredump since do_exit skips it. */
- seccomp_init_siginfo(&info, this_syscall, data);
- do_coredump(&info);
+ /* Dump core only if this is the last remaining thread. */
+ if (get_nr_threads(current) == 1) {
+ /* Show the original registers in the dump. */
+ syscall_rollback(current, task_pt_regs(current));
+ /* Trigger a manual coredump since do_exit skips it. */
+ seccomp_init_siginfo(&info, this_syscall, data);
+ do_coredump(&info);
+ }
do_exit(SIGSYS);
}
}
