From 35a9ff4eec7a1725ac4364972fc6c156e4feedd0 Mon Sep 17 00:00:00 2001 From: Quentin Casasnovas Date: Tue, 3 Feb 2015 13:00:24 +0100 Subject: 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 Cc: "H. Peter Anvin" Cc: Fenghua Yu 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 --- arch/x86/kernel/cpu/microcode/intel.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'arch/x86/kernel/cpu/microcode/intel.c') 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; -- cgit v1.2.3