From: ebiederm@xmission.com (Eric W. Biederman)
To: <linux-kernel@vger.kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Oleg Nesterov <oleg@redhat.com>,
Al Viro <viro@ZenIV.linux.org.uk>, <linux-api@vger.kernel.org>,
Kees Cook <keescook@chromium.org>
Subject: [PATCH 3/6] exec: Check for a pending fatal signal instead of core_state
Date: Thu, 23 Sep 2021 19:10:43 -0500 [thread overview]
Message-ID: <87fstux27w.fsf@disp2133> (raw)
In-Reply-To: <87v92qx2c6.fsf@disp2133> (Eric W. Biederman's message of "Thu, 23 Sep 2021 19:08:09 -0500")
Prevent exec continuing when a fatal signal is pending by replacing
mmap_read_lock with mmap_read_lock_killable. This is always the right
thing to do as userspace will never observe an exec complete when
there is a fatal signal pending.
With that change it becomes unnecessary to explicitly test for a core
dump in progress. In coredump_wait zap_threads arranges under
mmap_write_lock for all tasks that use a mm to also have SIGKILL
pending, which means mmap_read_lock_killable will always return -EINTR
when old_mm->core_state is present.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
fs/exec.c | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)
diff --git a/fs/exec.c b/fs/exec.c
index a098c133d8d7..b6079f1a098e 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -987,16 +987,14 @@ static int exec_mmap(struct mm_struct *mm)
if (old_mm) {
/*
- * Make sure that if there is a core dump in progress
- * for the old mm, we get out and die instead of going
- * through with the exec. We must hold mmap_lock around
- * checking core_state and changing tsk->mm.
+ * If there is a pending fatal signal perhaps a signal
+ * whose default action is to create a coredump get
+ * out and die instead of going through with the exec.
*/
- mmap_read_lock(old_mm);
- if (unlikely(old_mm->core_state)) {
- mmap_read_unlock(old_mm);
+ ret = mmap_read_lock_killable(old_mm);
+ if (ret) {
up_write(&tsk->signal->exec_update_lock);
- return -EINTR;
+ return ret;
}
}
--
2.20.1
next prev parent reply other threads:[~2021-09-24 0:10 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-24 0:08 [PATCH 0/6] per signal_struct coredumps Eric W. Biederman
2021-09-24 0:09 ` [PATCH 1/6] signal: Remove the bogus sigkill_pending in ptrace_stop Eric W. Biederman
2021-09-24 15:22 ` Kees Cook
2021-09-24 15:48 ` Eric W. Biederman
2021-09-24 19:06 ` Kees Cook
2021-09-24 0:10 ` [PATCH 2/6] ptrace: Remove the unnecessary arguments from arch_ptrace_stop Eric W. Biederman
2021-09-24 15:26 ` Kees Cook
2021-09-24 0:10 ` Eric W. Biederman [this message]
2021-09-24 15:38 ` [PATCH 3/6] exec: Check for a pending fatal signal instead of core_state Kees Cook
2021-09-24 0:11 ` [PATCH 4/6] exit: Factor coredump_exit_mm out of exit_mm Eric W. Biederman
2021-09-24 18:28 ` Kees Cook
2021-09-24 0:11 ` [PATCH 5/6] coredump: Don't perform any cleanups before dumping core Eric W. Biederman
2021-09-24 18:51 ` Kees Cook
2021-09-24 21:28 ` Eric W. Biederman
2021-09-24 21:41 ` Kees Cook
2021-09-24 0:12 ` [PATCH 6/6] coredump: Limit coredumps to a single thread group Eric W. Biederman
2021-09-24 18:56 ` Kees Cook
2021-10-06 17:03 ` Eric W. Biederman
2021-11-19 16:03 ` Kyle Huey
2021-11-19 17:38 ` Eric W. Biederman
2021-09-24 5:59 ` [PATCH 0/6] per signal_struct coredumps Kees Cook
2021-09-24 14:00 ` Eric W. Biederman
2021-09-24 15:22 ` [PATCH 2/6] ptrace: Remove the unnecessary arguments from arch_ptrace_stop Eric W. Biederman
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