Checksum should be unsigned 32-bit otherwise the calculation overflows
resulting in undefined behaviour:
[ 0.000000]
================================================================================
[ 0.000000] UBSAN: Undefined behaviour in
arch/x86/kernel/cpu/microcode/intel_lib.c:105:12
[ 0.000000] signed integer overflow:
[ 0.000000] -1500151068 + -2125470173 cannot be represented in type 'int'
[ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.5.0-rc5+ #495
[ 0.000000] 0000000000000086 0000000000000086 0000000000000000
ffffffff83203968
[ 0.000000] ffffffff81b30952 ffffffff834c43b8 ffffffff83203998
ffffffff814fe623
[ 0.000000] ffffffff83203980 ffffffff81bcdf2d ffffffff8339a448
ffffffff83203a08
[ 0.000000] Call Trace:
[ 0.000000] [<ffffffff81b30952>] dump_stack+0x4e/0x6c
[ 0.000000] [<ffffffff814fe623>] ? inotify_ioctl+0x43/0x1c0
[ 0.000000] [<ffffffff81bcdf2d>] ubsan_epilogue+0xd/0x40
[ 0.000000] [<ffffffff81bce2fd>] handle_overflow+0xbd/0xe0
[ 0.000000] [<ffffffff81bce32e>] __ubsan_handle_add_overflow+0xe/0x10
[ 0.000000] [<ffffffff81148e45>] microcode_sanity_check+0x405/0x590
[ 0.000000] [<ffffffff8549b01b>]
get_matching_model_microcode.isra.2.constprop.8+0xa5/0x345
[ 0.000000] [<ffffffff8548615d>] ? early_idt_handler_common+0x3d/0xae
[ 0.000000] [<ffffffff81b50962>] ? strlcpy+0x52/0xa0
[ 0.000000] [<ffffffff81b30ce1>] ? find_cpio_data+0x371/0x510
[ 0.000000] [<ffffffff8549b461>] load_ucode_intel_bsp+0xa1/0xe5
[ 0.000000] [<ffffffff8549aea8>] load_ucode_bsp+0xdf/0xf3
[ 0.000000] [<ffffffff8549aea8>] ? load_ucode_bsp+0xdf/0xf3
[ 0.000000] [<ffffffff8548671c>] x86_64_start_kernel+0xd1/0xee
[ 0.000000]
================================================================================
Signed-off-by: Chris Bainbridge <chris.bainbri...@gmail.com>
---
arch/x86/kernel/cpu/microcode/intel_lib.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/cpu/microcode/intel_lib.c
b/arch/x86/kernel/cpu/microcode/intel_lib.c
index b96896bcbdaf..2bef93ff2e3f 100644
--- a/arch/x86/kernel/cpu/microcode/intel_lib.c
+++ b/arch/x86/kernel/cpu/microcode/intel_lib.c
@@ -49,7 +49,7 @@ int microcode_sanity_check(void *mc, int print_err)
unsigned long total_size, data_size, ext_table_size;
struct microcode_header_intel *mc_header = mc;
struct extended_sigtable *ext_header = NULL;
- int sum, orig_sum, ext_sigcount = 0, i;
+ u32 sum, orig_sum, ext_sigcount = 0, i;
struct extended_signature *ext_sig;
total_size = get_totalsize(mc_header);
--
2.1.4
