From 6db9dccc57637fa8a7ce90a7019e76f8b9e70d1d Mon Sep 17 00:00:00 2001 From: Tim Wawrzynczak Date: Wed, 7 Jul 2021 13:47:47 -0600 Subject: [PATCH] soc/intel: Fix microcode loading Commit 1aa60a95bd8363d2 broke microcode loading for chipsets that have a microcode blob with a total_size field set to 0. This appears to be support for older chipsets, where the size was set to 0 and assumed to be 2048 bytes. The fix is to change the result of the subtraction to a signed type, and ensure the following comparison is done without promoting the signed type to an unsigned one. Resolves: https://ticket.coreboot.org/issues/313 Change-Id: I62def8014fd3f3bbf607b4d58ddc4dca4c695622 Signed-off-by: Tim Wawrzynczak Reviewed-on: https://review.coreboot.org/c/coreboot/+/56153 Reviewed-by: Furquan Shaikh Reviewed-by: Nico Huber Reviewed-by: Stefan Ott Tested-by: build bot (Jenkins) --- src/cpu/intel/microcode/microcode.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/src/cpu/intel/microcode/microcode.c b/src/cpu/intel/microcode/microcode.c index 45996dfdc3..469bd25496 100644 --- a/src/cpu/intel/microcode/microcode.c +++ b/src/cpu/intel/microcode/microcode.c @@ -136,9 +136,9 @@ static struct ext_sig_table *ucode_get_ext_sig_table(const struct microcode *uco /* header + ucode data blob size */ u32 size = ucode->data_size + sizeof(struct microcode); - size_t ext_tbl_len = ucode->total_size - size; + ssize_t ext_tbl_len = ucode->total_size - size; - if (ext_tbl_len < sizeof(struct ext_sig_table)) + if (ext_tbl_len < (ssize_t)sizeof(struct ext_sig_table)) return NULL; ext_tbl = (struct ext_sig_table *)((uintptr_t)ucode + size);