From 465d377701dfe6a08a9f361a3fd926dea7f89c74 Mon Sep 17 00:00:00 2001
From: Russell King <rmk+kernel@arm.linux.org.uk>
Date: Tue, 2 Aug 2016 14:05:57 -0700
Subject: [PATCH] kexec: ensure user memory sizes do not wrap

Ensure that user memory sizes do not wrap around when validating the
user input, which can lead to the following input validation working
incorrectly.

[akpm@linux-foundation.org: fix it for kexec-return-error-number-directly.patch]
Link: http://lkml.kernel.org/r/E1b8koF-0004HM-5x@rmk-PC.armlinux.org.uk
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Reviewed-by: Pratyush Anand <panand@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Keerthy <j-keerthy@ti.com>
Cc: Vitaly Andrianov <vitalya@ti.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Simon Horman <horms@verge.net.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 kernel/kexec_core.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index 23311c803b1b..5a83b2a9d584 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -168,6 +168,8 @@ int sanity_check_segment_list(struct kimage *image)
 
 		mstart = image->segment[i].mem;
 		mend   = mstart + image->segment[i].memsz;
+		if (mstart > mend)
+			return -EADDRNOTAVAIL;
 		if ((mstart & ~PAGE_MASK) || (mend & ~PAGE_MASK))
 			return -EADDRNOTAVAIL;
 		if (mend >= KEXEC_DESTINATION_MEMORY_LIMIT)
-- 
2.20.1