[PATCH 1/6] x86/KASLR: Handle kernel relocation above 2G

[Kees Cook]

From: Baoquan He <bhe@xxxxxxxxxx>

When processing the relocation table, the offset used to calculate the
relocation is an int. This is sufficient for calculating the physical
address of the relocs entry on 32-bit systems and on 64-bit systems when
the relocation is under 2G. To handle relocations above 2G (seen in
situations like kexec, netboot, etc), this offset needs to be calculated
using a long to avoid wrapping and miscalculating the relocation.

Signed-off-by: Baoquan He <bhe@xxxxxxxxxx>
[kees: rewrote changelog]
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
 arch/x86/boot/compressed/misc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index 6dde6ccdf00e..45145149c07d 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -232,7 +232,7 @@ static void handle_relocations(void *output, unsigned long output_len)
 	 * So we work backwards from the end of the decompressed image.
 	 */
 	for (reloc = output + output_len - sizeof(*reloc); *reloc; reloc--) {
-		int extended = *reloc;
+		long extended = *reloc;
 		extended += map;
 
 		ptr = (unsigned long)extended;
-- 
2.6.3