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Patch "arm: oabi compat: add missing access checks" has been added to the 3.14-stable tree

PATCH [email protected] 1 participant 1 message Aug 14, 2016

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

arm: oabi compat: add missing access checks

to the 3.14-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:
arm-oabi-compat-add-missing-access-checks.patch
and it can be found in the queue-3.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From 7de249964f5578e67b99699c5f0b405738d820a2 Mon Sep 17 00:00:00 2001

From: Dave Weinstein <[email protected]>
Date: Thu, 28 Jul 2016 11:55:41 -0700
Subject: arm: oabi compat: add missing access checks

From: Dave Weinstein <[email protected]>

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.

---
 arch/arm/kernel/sys_oabi-compat.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)
arch/arm/kernel/sys_oabi-compat.c +7 -1
@@ -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;

Patches currently in stable-queue which might be from [email protected] are

queue-3.14/arm-oabi-compat-add-missing-access-checks.patch