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>

diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index 23311c8..5a83b2a 100644 (file)
--- 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)