From d7276e321ff8a53106a59c85ca46d03e34288893 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Tue, 7 Feb 2017 15:18:51 -0800 Subject: [PATCH] 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 Acked-by: Andrei Vagin Signed-off-by: James Morris --- kernel/seccomp.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/kernel/seccomp.c b/kernel/seccomp.c index f8f88ebcb3ba..e15185c28de5 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); } } -- 2.30.2