From: Kees Cook keescook@chromium.org
stable inclusion from stable-v5.10.150 commit 6ed7b05a3592e96023989417f617f80a5e25dedd category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I6D0XA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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[ Upstream commit 712f210a457d9c32414df246a72781550bc23ef6 ]
In preparation for reducing the use of ksize(), record the actual allocation size for later memcpy(). This avoids copying extra (uninitialized!) bytes into the patch buffer when the requested allocation size isn't exactly the size of a kmalloc bucket. Additionally, fix potential future issues where runtime bounds checking will notice that the buffer was allocated to a smaller value than returned by ksize().
Fixes: 757885e94a22 ("x86, microcode, amd: Early microcode patch loading support for AMD") Suggested-by: Daniel Micay danielmicay@gmail.com Signed-off-by: Kees Cook keescook@chromium.org Signed-off-by: Borislav Petkov bp@suse.de Link: https://lore.kernel.org/lkml/CA+DvKQ+bp7Y7gmaVhacjv9uF6Ar-o4tet872h4Q8RPYPJj... Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Jialin Zhang zhangjialin11@huawei.com --- arch/x86/include/asm/microcode.h | 1 + arch/x86/kernel/cpu/microcode/amd.c | 3 ++- 2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/microcode.h b/arch/x86/include/asm/microcode.h index 91a06cef50c1..f73327397b89 100644 --- a/arch/x86/include/asm/microcode.h +++ b/arch/x86/include/asm/microcode.h @@ -9,6 +9,7 @@ struct ucode_patch { struct list_head plist; void *data; /* Intel uses only this one */ + unsigned int size; u32 patch_id; u16 equiv_cpu; }; diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c index 3f6b137ef4e6..c87936441339 100644 --- a/arch/x86/kernel/cpu/microcode/amd.c +++ b/arch/x86/kernel/cpu/microcode/amd.c @@ -783,6 +783,7 @@ static int verify_and_add_patch(u8 family, u8 *fw, unsigned int leftover, kfree(patch); return -EINVAL; } + patch->size = *patch_size;
mc_hdr = (struct microcode_header_amd *)(fw + SECTION_HDR_SIZE); proc_id = mc_hdr->processor_rev_id; @@ -864,7 +865,7 @@ load_microcode_amd(bool save, u8 family, const u8 *data, size_t size) return ret;
memset(amd_ucode_patch, 0, PATCH_MAX_SIZE); - memcpy(amd_ucode_patch, p->data, min_t(u32, ksize(p->data), PATCH_MAX_SIZE)); + memcpy(amd_ucode_patch, p->data, min_t(u32, p->size, PATCH_MAX_SIZE));
return ret; }