Patch "arm64: ensure __dump_instr() checks addr_limit" has been added to the 4.9-stable tree

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

arm64: ensure __dump_instr() checks addr_limit

to the 4.9-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:
arm64-ensure-__dump_instr-checks-addr_limit.patch
and it can be found in the queue-4.9 subdirectory.

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

From: Mark Rutland <[email protected]>
Date: Thu, 2 Nov 2017 16:12:03 +0000
Subject: arm64: ensure __dump_instr() checks addr_limit

From: Mark Rutland <[email protected]>

commit 7a7003b1da010d2b0d1dc8bf21c10f5c73b389f1 upstream.

It's possible for a user to deliberately trigger __dump_instr with a chosen kernel address.

Let's avoid problems resulting from this by using get_user() rather than __get_user(), ensuring that we don't erroneously access kernel memory.

Where we use __dump_instr() on kernel text, we already switch to KERNEL_DS, so this shouldn't adversely affect those cases.

---
 arch/arm64/kernel/traps.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -112,7 +112,7 @@ static void __dump_instr(const char *lvl
 	for (i = -4; i < 1; i++) {
 		unsigned int val, bad;
 
-		bad = __get_user(val, &((u32 *)addr)[i]);
+		bad = get_user(val, &((u32 *)addr)[i]);
 
 		if (!bad)
 			p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val);

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

queue-4.9/arm64-ensure-__dump_instr-checks-addr_limit.patch