This is a note to let you know that I've just added the patch titled
x86/microcode/intel: Guard against stack overflow in the loader
to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-microcode-intel-guard-against-stack-overflow-in-the-loader.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From f84598bd7c851f8b0bf8cd0d7c3be0d73c432ff4 Mon Sep 17 00:00:00 2001
From: Quentin Casasnovas <quentin.casasnovas@xxxxxxxxxx>
Date: Tue, 3 Feb 2015 13:00:22 +0100
Subject: x86/microcode/intel: Guard against stack overflow in the loader
From: Quentin Casasnovas <quentin.casasnovas@xxxxxxxxxx>
commit f84598bd7c851f8b0bf8cd0d7c3be0d73c432ff4 upstream.
mc_saved_tmp is a static array allocated on the stack, we need to make
sure mc_saved_count stays within its bounds, otherwise we're overflowing
the stack in _save_mc(). A specially crafted microcode header could lead
to a kernel crash or potentially kernel execution.
Signed-off-by: Quentin Casasnovas <quentin.casasnovas@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Link: http://lkml.kernel.org/r/1422964824-22056-1-git-send-email-quentin.casasnovas@xxxxxxxxxx
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/cpu/microcode/intel_early.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/kernel/cpu/microcode/intel_early.c
+++ b/arch/x86/kernel/cpu/microcode/intel_early.c
@@ -321,7 +321,7 @@ get_matching_model_microcode(int cpu, un
unsigned int mc_saved_count = mc_saved_data->mc_saved_count;
int i;
- while (leftover) {
+ while (leftover && mc_saved_count < ARRAY_SIZE(mc_saved_tmp)) {
mc_header = (struct microcode_header_intel *)ucode_ptr;
mc_size = get_totalsize(mc_header);
Patches currently in stable-queue which might be from quentin.casasnovas@xxxxxxxxxx are
queue-3.14/x86-microcode-intel-guard-against-stack-overflow-in-the-loader.patch
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