Messages in this thread Patch in this message | | | From | Borislav Petkov <> | Subject | [PATCH 2/2] x86/microcode/AMD: Handle multiple glued containers properly | Date | Mon, 19 Dec 2022 22:06:56 +0100 |
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From: Borislav Petkov <bp@suse.de>
It can happen that - especially during testing - the microcode blobs of all families are all glued together in the initrd. The current code doesn't check whether the current container matched a microcode patch and continues to the next one, which leads to save_microcode_in_initrd_amd() to look at the next and thus wrong one:
microcode: parse_container: ucode: 0xffff88807e9d9082 microcode: verify_patch: buf: 0xffff88807e9d90ce, buf_size: 26428 microcode: verify_patch: proc_id: 0x8082, patch_fam: 0x17, this family: 0x17 microcode: verify_patch: buf: 0xffff88807e9d9d56, buf_size: 23220 microcode: verify_patch: proc_id: 0x8012, patch_fam: 0x17, this family: 0x17 microcode: parse_container: MATCH: eq_id: 0x8012, patch proc_rev_id: 0x8012
<-- matching patch found
microcode: verify_patch: buf: 0xffff88807e9da9de, buf_size: 20012 microcode: verify_patch: proc_id: 0x8310, patch_fam: 0x17, this family: 0x17 microcode: verify_patch: buf: 0xffff88807e9db666, buf_size: 16804 microcode: Invalid type field (0x414d44) in container file section header. microcode: Patch section fail
<-- checking chokes on the microcode magic value of the next container.
microcode: parse_container: saving container 0xffff88807e9d9082 microcode: save_microcode_in_initrd_amd: scanned containers, data: 0xffff88807e9d9082, size: 9700a
and now if there's a next (and last container) it'll use that in save_microcode_in_initrd_amd() and not find a proper patch, ofc.
Fix that by moving the out: label up, before the desc->mc check which jots down the pointer of the matching patch and is used to signal to the caller that it has found a matching patch in the current container.
Signed-off-by: Borislav Petkov <bp@suse.de> --- arch/x86/kernel/cpu/microcode/amd.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c index 339c9666c8bc..d144f918a896 100644 --- a/arch/x86/kernel/cpu/microcode/amd.c +++ b/arch/x86/kernel/cpu/microcode/amd.c @@ -330,8 +330,9 @@ static size_t parse_container(u8 *ucode, size_t size, struct cont_desc *desc) ret = verify_patch(x86_family(desc->cpuid_1_eax), buf, size, &patch_size, true); if (ret < 0) { /* - * Patch verification failed, skip to the next - * container, if there's one: + * Patch verification failed, skip to the next container, if + * there is one. Before exit, check whether that container has + * found a patch already. If so, use it. */ goto out; } else if (ret > 0) { @@ -350,6 +351,7 @@ static size_t parse_container(u8 *ucode, size_t size, struct cont_desc *desc) size -= patch_size + SECTION_HDR_SIZE; } +out: /* * If we have found a patch (desc->mc), it means we're looking at the * container which has a patch for this CPU so return 0 to mean, @ucode @@ -364,7 +366,6 @@ static size_t parse_container(u8 *ucode, size_t size, struct cont_desc *desc) return 0; } -out: return orig_size - size; } -- 2.35.1
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