Patch "waitid(): Add missing access_ok() checks" has been added to the 4.13-stable tree

Patch "waitid(): Add missing access_ok() checks" has been added to the 4.13-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    waitid(): Add missing access_ok() checks

to the 4.13-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     waitid-add-missing-access_ok-checks.patch
and it can be found in the queue-4.13 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 96ca579a1ecc943b75beba58bebb0356f6cc4b51 Mon Sep 17 00:00:00 2001
From: Kees Cook <keescook@chromium.org>
Date: Mon, 9 Oct 2017 11:36:52 -0700
Subject: waitid(): Add missing access_ok() checks

From: Kees Cook <keescook@chromium.org>

commit 96ca579a1ecc943b75beba58bebb0356f6cc4b51 upstream.

Adds missing access_ok() checks.

CVE-2017-5123

Reported-by: Chris Salls <chrissalls5@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Fixes: 4c48abe91be0 ("waitid(): switch copyout of siginfo to unsafe_put_user()")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 kernel/exit.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1611,6 +1611,9 @@ SYSCALL_DEFINE5(waitid, int, which, pid_
 	if (!infop)
 		return err;
 
+	if (!access_ok(VERIFY_WRITE, infop, sizeof(*infop)))
+		goto Efault;
+
 	user_access_begin();
 	unsafe_put_user(signo, &infop->si_signo, Efault);
 	unsafe_put_user(0, &infop->si_errno, Efault);
@@ -1736,6 +1739,9 @@ COMPAT_SYSCALL_DEFINE5(waitid,
 	if (!infop)
 		return err;
 
+	if (!access_ok(VERIFY_WRITE, infop, sizeof(*infop)))
+		goto Efault;
+
 	user_access_begin();
 	unsafe_put_user(signo, &infop->si_signo, Efault);
 	unsafe_put_user(0, &infop->si_errno, Efault);


Patches currently in stable-queue which might be from keescook@chromium.org are

queue-4.13/waitid-add-missing-access_ok-checks.patch