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Commit 7de24996 authored by Dave Weinstein's avatar Dave Weinstein Committed by Linus Torvalds
Browse files

arm: oabi compat: add missing access checks 



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.

Cc: stable@vger.kernel.org
Reported-by: default avatarChiachih Wu <wuchiachih@gmail.com>
Reviewed-by: default avatarKees Cook <keescook@chromium.org>
Reviewed-by: default avatarNicolas Pitre <nico@linaro.org>
Signed-off-by: default avatarDave Weinstein <olorin@google.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 9512c47e

arch/arm/kernel/sys_oabi-compat.c

+7 −1
Original line number Diff line number Diff line
@@ -279,8 +279,12 @@ asmlinkage long sys_oabi_epoll_wait(int epfd, 
	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;
@@ -317,6 +321,8 @@ asmlinkage long sys_oabi_semtimedop(int semid, 


	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;