From d496a002ae1f02425168e5211c237abee588651a Mon Sep 17 00:00:00 2001 From: Quentin Casasnovas Date: Thu, 26 Feb 2015 18:03:59 +0100 Subject: [PATCH] x86/microcode/intel: Fix out of bounds memory access to the extended header Improper pointer arithmetics when calculating the address of the extended header could lead to an out of bounds memory read and kernel panic. Signed-off-by: Quentin Casasnovas Link: http://lkml.kernel.org/r/20150225094125.GB30434@chrystal.uk.oracle.com Signed-off-by: Borislav Petkov --- arch/x86/kernel/cpu/microcode/intel_early.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/cpu/microcode/intel_early.c b/arch/x86/kernel/cpu/microcode/intel_early.c index 420eb93..3a6c613 100644 --- a/arch/x86/kernel/cpu/microcode/intel_early.c +++ b/arch/x86/kernel/cpu/microcode/intel_early.c @@ -180,8 +180,7 @@ matching_model_microcode(struct microcode_header_intel *mc_header, if (total_size <= data_size + MC_HEADER_SIZE) return UCODE_NFOUND; - ext_header = (struct extended_sigtable *) - mc_header + data_size + MC_HEADER_SIZE; + ext_header = (void *) mc_header + data_size + MC_HEADER_SIZE; ext_sigcount = ext_header->count; ext_sig = (void *)ext_header + EXT_HEADER_SIZE; @@ -457,8 +456,7 @@ static void __ref show_saved_mc(void) if (total_size <= data_size + MC_HEADER_SIZE) continue; - ext_header = (struct extended_sigtable *) - mc_saved_header + data_size + MC_HEADER_SIZE; + ext_header = (void *) mc_saved_header + data_size + MC_HEADER_SIZE; ext_sigcount = ext_header->count; ext_sig = (void *)ext_header + EXT_HEADER_SIZE; -- 2.7.4