x86/KASLR: Handle kernel relocations above 2G correctly

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 <[email protected]>
[ Rewrote the changelog. ]
Signed-off-by: Kees Cook <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Dave Young <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Vivek Goyal <[email protected]>
Cc: Yinghai Lu <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

Signed-off-by: Ingo Molnar <[email protected]>

1 files changed, 1 insertions, 1 deletions

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;