[PATCH 4/8] kexec: ensure user memory sizes do not wrap

[Russell King]

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

Acked-by: Baoquan He <bhe at redhat.com>
Reviewed-by: Pratyush Anand <panand at redhat.com>
Signed-off-by: Russell King <rmk+kernel at arm.linux.org.uk>
---
 kernel/kexec_core.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index 8d34308ea449..d719a4d0ef55 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -169,6 +169,8 @@ int sanity_check_segment_list(struct kimage *image)
 
 		mstart = image->segment[i].mem;
 		mend   = mstart + image->segment[i].memsz;
+		if (mstart > mend)
+			return result;
 		if ((mstart & ~PAGE_MASK) || (mend & ~PAGE_MASK))
 			return result;
 		if (mend >= KEXEC_DESTINATION_MEMORY_LIMIT)
-- 
2.1.0