4.13-stable review patch. If anyone has any objections, please let me know.
------------------
From: Kees Cook <keescook@xxxxxxxxxxxx>
commit 96ca579a1ecc943b75beba58bebb0356f6cc4b51 upstream.
Adds missing access_ok() checks.
CVE-2017-5123
Reported-by: Chris Salls <chrissalls5@xxxxxxxxx>
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Acked-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Fixes: 4c48abe91be0 ("waitid(): switch copyout of siginfo to unsafe_put_user()")
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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);