blob: c3d125284d39b2f9124ea42a5d29cced4726b6d4 [file] [log] [blame]
From: Dave Weinstein <olorin@google.com>
Date: Thu, 28 Jul 2016 11:55:41 -0700
Subject: arm: oabi compat: add missing access checks
commit 7de249964f5578e67b99699c5f0b405738d820a2 upstream.
Add access checks to sys_oabi_epoll_wait() and sys_oabi_semtimedop().
This fixes CVE-2016-3857, a local privilege escalation under
CONFIG_OABI_COMPAT.
Reported-by: Chiachih Wu <wuchiachih@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Dave Weinstein <olorin@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
arch/arm/kernel/sys_oabi-compat.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
--- a/arch/arm/kernel/sys_oabi-compat.c
+++ b/arch/arm/kernel/sys_oabi-compat.c
@@ -275,8 +275,12 @@ asmlinkage long sys_oabi_epoll_wait(int
mm_segment_t fs;
long ret, err, i;
- if (maxevents <= 0 || maxevents > (INT_MAX/sizeof(struct epoll_event)))
+ if (maxevents <= 0 ||
+ maxevents > (INT_MAX/sizeof(*kbuf)) ||
+ maxevents > (INT_MAX/sizeof(*events)))
return -EINVAL;
+ if (!access_ok(VERIFY_WRITE, events, sizeof(*events) * maxevents))
+ return -EFAULT;
kbuf = kmalloc(sizeof(*kbuf) * maxevents, GFP_KERNEL);
if (!kbuf)
return -ENOMEM;
@@ -313,6 +317,8 @@ asmlinkage long sys_oabi_semtimedop(int
if (nsops < 1 || nsops > SEMOPM)
return -EINVAL;
+ if (!access_ok(VERIFY_READ, tsops, sizeof(*tsops) * nsops))
+ return -EFAULT;
sops = kmalloc(sizeof(*sops) * nsops, GFP_KERNEL);
if (!sops)
return -ENOMEM;