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authorQuentin Casasnovas <quentin.casasnovas@oracle.com>2015-02-03 13:00:24 +0100
committerBorislav Petkov <bp@suse.de>2015-02-19 12:42:23 +0100
commit35a9ff4eec7a1725ac4364972fc6c156e4feedd0 (patch)
treed77433b391eb3f7e9f85d46b720af0cd17be85f7 /arch/x86
parentf84598bd7c851f8b0bf8cd0d7c3be0d73c432ff4 (diff)
downloadlinux-35a9ff4eec7a1725ac4364972fc6c156e4feedd0.tar.bz2
x86/microcode/intel: Handle truncated microcode images more robustly
We do not check the input data bounds containing the microcode before copying a struct microcode_intel_header from it. A specially crafted microcode could cause the kernel to read invalid memory and lead to a denial-of-service. Signed-off-by: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Link: http://lkml.kernel.org/r/1422964824-22056-3-git-send-email-quentin.casasnovas@oracle.com [ Made error message differ from the next one and flipped comparison. ] Signed-off-by: Borislav Petkov <bp@suse.de>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kernel/cpu/microcode/intel.c5
-rw-r--r--arch/x86/kernel/cpu/microcode/intel_early.c4
2 files changed, 9 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index c6826d1e8082..746e7fd08aad 100644
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -196,6 +196,11 @@ static enum ucode_state generic_load_microcode(int cpu, void *data, size_t size,
struct microcode_header_intel mc_header;
unsigned int mc_size;
+ if (leftover < sizeof(mc_header)) {
+ pr_err("error! Truncated header in microcode data file\n");
+ break;
+ }
+
if (get_ucode_data(&mc_header, ucode_ptr, sizeof(mc_header)))
break;
diff --git a/arch/x86/kernel/cpu/microcode/intel_early.c b/arch/x86/kernel/cpu/microcode/intel_early.c
index 5e109a31f62b..420eb933189c 100644
--- a/arch/x86/kernel/cpu/microcode/intel_early.c
+++ b/arch/x86/kernel/cpu/microcode/intel_early.c
@@ -322,6 +322,10 @@ get_matching_model_microcode(int cpu, unsigned long start,
int i;
while (leftover && mc_saved_count < ARRAY_SIZE(mc_saved_tmp)) {
+
+ if (leftover < sizeof(mc_header))
+ break;
+
mc_header = (struct microcode_header_intel *)ucode_ptr;
mc_size = get_totalsize(mc_header);