Re: [PATCH v6 5/8] x86/microcode/AMD: Check microcode container data in the late loader

[Borislav Petkov]

On Sun, May 20, 2018 at 12:07:19AM +0200, Maciej S. Szmigiero wrote:
> Convert the late loader in the AMD microcode update driver to use newly
> introduced microcode container data checking functions as it was previously
> done for the early loader.
> 
> Signed-off-by: Maciej S. Szmigiero 
> ---
>  arch/x86/kernel/cpu/microcode/amd.c | 70 +
>  1 file changed, 32 insertions(+), 38 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/microcode/amd.c 
> b/arch/x86/kernel/cpu/microcode/amd.c
> index f8bd74341ed8..3e10a5920f58 100644
> --- a/arch/x86/kernel/cpu/microcode/amd.c
> +++ b/arch/x86/kernel/cpu/microcode/amd.c
> @@ -693,28 +693,26 @@ static enum ucode_state apply_microcode_amd(int cpu)
>   return UCODE_UPDATED;
>  }
>  
> -static int install_equiv_cpu_table(const u8 *buf)
> +static unsigned int install_equiv_cpu_table(const u8 *buf, size_t buf_size)
>  {
> - unsigned int *ibuf = (unsigned int *)buf;
> - unsigned int type = ibuf[1];
> - unsigned int size = ibuf[2];
> + const u32 *hdr;
> + u32 equiv_tbl_len;
>  
> - if (type != UCODE_EQUIV_CPU_TABLE_TYPE || !size) {
> - pr_err("empty section/"
> -"invalid type field in container file section header\n");
> - return -EINVAL;
> - }
> + if (!verify_equivalence_table(buf, buf_size, false))
> + return 0;
> +
> + hdr = (const u32 *)buf;
> + equiv_tbl_len = hdr[2];
>  
> - equiv_cpu_table = vmalloc(size);
> + equiv_cpu_table = vmalloc(equiv_tbl_len);
>   if (!equiv_cpu_table) {
>   pr_err("failed to allocate equivalent CPU table\n");
> - return -ENOMEM;
> + return 0;
>   }
>  
> - memcpy(equiv_cpu_table, buf + CONTAINER_HDR_SZ, size);
> + memcpy(equiv_cpu_table, buf + CONTAINER_HDR_SZ, equiv_tbl_len);
>  
> - /* add header length */
> - return size + CONTAINER_HDR_SZ;
> + return equiv_tbl_len;
>  }
>  
>  static void free_equiv_cpu_table(void)
> @@ -739,13 +737,19 @@ static void cleanup(void)
>  static int verify_and_add_patch(u8 family, u8 *fw, unsigned int leftover,
>   unsigned int *crnt_size)
>  {
> + u32 *hdr = (u32 *)fw;
>   struct microcode_header_amd *mc_hdr;
>   struct ucode_patch *patch;
> - unsigned int patch_size, ret;
> + u32 patch_size;
>   u32 proc_fam;
>   u16 proc_id;
>  
> - patch_size  = *(u32 *)(fw + 4);
> + if (!verify_patch_section(fw, leftover, false)) {
> + *crnt_size = leftover;

I'm not sure about this: we verify the patch section and in the error
case we skip over the whole leftover buffer?

Maybe skipping over SECTION_HDR_SIZE or better yet skip 1 byte here
too, like in parse_container() to give us the highest chance of finding
something sensible later...

> + return 0;
> + }
> +
> + patch_size  = hdr[1];

Same comment as before: verify_patch_size()

But I think you can simply do verify_patch() at the beginning of the
function and be done with the verification in that function.

>   *crnt_size  = patch_size + SECTION_HDR_SIZE;
>   mc_hdr  = (struct microcode_header_amd *)(fw + SECTION_HDR_SIZE);
>   proc_id = mc_hdr->processor_rev_id;
> @@ -767,16 +771,8 @@ static int verify_and_add_patch(u8 family, u8 *fw, 
> unsigned int leftover,
>   return 0;
>   }
>  
> - /*
> -  * The section header length is not included in this indicated size
> -  * but is present in the leftover file length so we need to subtract
> -  * it before passing this value to the function below.
> -  */
> - ret = verify_patch_size(family, patch_size, leftover - 
> SECTION_HDR_SIZE);
> - if (!ret) {
> - pr_err("Patch-ID 0x%08x: size mismatch.\n", mc_hdr->patch_id);
> + if (!verify_patch(family, fw, leftover, false))
>   return 0;
> - }
>  
>   patch = kzalloc(sizeof(*patch), GFP_KERNEL);
>   if (!patch) {
> @@ -810,21 +806,21 @@ static enum ucode_state __load_microcode_amd(u8 family, 
> const u8 *data,
>   enum ucode_state ret = UCODE_ERROR;
>   unsigned int leftover;
>   u8 *fw = (u8 *)data;
> - int offset;
> + unsigned int offset;
>  
> - offset = install_equiv_cpu_table(data);
> - if (offset < 0) {
> + offset = install_equiv_cpu_table(data, size);
> + if (!offset) {
>   pr_err("failed to create equivalent cpu table\n");

No need for that error message anymore I guess -
install_equiv_cpu_table() and verify_equivalence_table() are pretty
vocal in the error case already.

-- 
Regards/Gruss,
Boris.

ECO tip #101: Trim your mails when you reply.
--

Re: [PATCH v6 5/8] x86/microcode/AMD: Check microcode container data in the late loader

[Borislav Petkov]

On Sun, May 20, 2018 at 12:07:19AM +0200, Maciej S. Szmigiero wrote:
> Convert the late loader in the AMD microcode update driver to use newly
> introduced microcode container data checking functions as it was previously
> done for the early loader.
> 
> Signed-off-by: Maciej S. Szmigiero 
> ---
>  arch/x86/kernel/cpu/microcode/amd.c | 70 +
>  1 file changed, 32 insertions(+), 38 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/microcode/amd.c 
> b/arch/x86/kernel/cpu/microcode/amd.c
> index f8bd74341ed8..3e10a5920f58 100644
> --- a/arch/x86/kernel/cpu/microcode/amd.c
> +++ b/arch/x86/kernel/cpu/microcode/amd.c
> @@ -693,28 +693,26 @@ static enum ucode_state apply_microcode_amd(int cpu)
>   return UCODE_UPDATED;
>  }
>  
> -static int install_equiv_cpu_table(const u8 *buf)
> +static unsigned int install_equiv_cpu_table(const u8 *buf, size_t buf_size)
>  {
> - unsigned int *ibuf = (unsigned int *)buf;
> - unsigned int type = ibuf[1];
> - unsigned int size = ibuf[2];
> + const u32 *hdr;
> + u32 equiv_tbl_len;
>  
> - if (type != UCODE_EQUIV_CPU_TABLE_TYPE || !size) {
> - pr_err("empty section/"
> -"invalid type field in container file section header\n");
> - return -EINVAL;
> - }
> + if (!verify_equivalence_table(buf, buf_size, false))
> + return 0;
> +
> + hdr = (const u32 *)buf;
> + equiv_tbl_len = hdr[2];
>  
> - equiv_cpu_table = vmalloc(size);
> + equiv_cpu_table = vmalloc(equiv_tbl_len);
>   if (!equiv_cpu_table) {
>   pr_err("failed to allocate equivalent CPU table\n");
> - return -ENOMEM;
> + return 0;
>   }
>  
> - memcpy(equiv_cpu_table, buf + CONTAINER_HDR_SZ, size);
> + memcpy(equiv_cpu_table, buf + CONTAINER_HDR_SZ, equiv_tbl_len);
>  
> - /* add header length */
> - return size + CONTAINER_HDR_SZ;
> + return equiv_tbl_len;
>  }
>  
>  static void free_equiv_cpu_table(void)
> @@ -739,13 +737,19 @@ static void cleanup(void)
>  static int verify_and_add_patch(u8 family, u8 *fw, unsigned int leftover,
>   unsigned int *crnt_size)
>  {
> + u32 *hdr = (u32 *)fw;
>   struct microcode_header_amd *mc_hdr;
>   struct ucode_patch *patch;
> - unsigned int patch_size, ret;
> + u32 patch_size;
>   u32 proc_fam;
>   u16 proc_id;
>  
> - patch_size  = *(u32 *)(fw + 4);
> + if (!verify_patch_section(fw, leftover, false)) {
> + *crnt_size = leftover;

I'm not sure about this: we verify the patch section and in the error
case we skip over the whole leftover buffer?

Maybe skipping over SECTION_HDR_SIZE or better yet skip 1 byte here
too, like in parse_container() to give us the highest chance of finding
something sensible later...

> + return 0;
> + }
> +
> + patch_size  = hdr[1];

Same comment as before: verify_patch_size()

But I think you can simply do verify_patch() at the beginning of the
function and be done with the verification in that function.

>   *crnt_size  = patch_size + SECTION_HDR_SIZE;
>   mc_hdr  = (struct microcode_header_amd *)(fw + SECTION_HDR_SIZE);
>   proc_id = mc_hdr->processor_rev_id;
> @@ -767,16 +771,8 @@ static int verify_and_add_patch(u8 family, u8 *fw, 
> unsigned int leftover,
>   return 0;
>   }
>  
> - /*
> -  * The section header length is not included in this indicated size
> -  * but is present in the leftover file length so we need to subtract
> -  * it before passing this value to the function below.
> -  */
> - ret = verify_patch_size(family, patch_size, leftover - 
> SECTION_HDR_SIZE);
> - if (!ret) {
> - pr_err("Patch-ID 0x%08x: size mismatch.\n", mc_hdr->patch_id);
> + if (!verify_patch(family, fw, leftover, false))
>   return 0;
> - }
>  
>   patch = kzalloc(sizeof(*patch), GFP_KERNEL);
>   if (!patch) {
> @@ -810,21 +806,21 @@ static enum ucode_state __load_microcode_amd(u8 family, 
> const u8 *data,
>   enum ucode_state ret = UCODE_ERROR;
>   unsigned int leftover;
>   u8 *fw = (u8 *)data;
> - int offset;
> + unsigned int offset;
>  
> - offset = install_equiv_cpu_table(data);
> - if (offset < 0) {
> + offset = install_equiv_cpu_table(data, size);
> + if (!offset) {
>   pr_err("failed to create equivalent cpu table\n");

No need for that error message anymore I guess -
install_equiv_cpu_table() and verify_equivalence_table() are pretty
vocal in the error case already.

-- 
Regards/Gruss,
Boris.

ECO tip #101: Trim your mails when you reply.
--

[PATCH v6 5/8] x86/microcode/AMD: Check microcode container data in the late loader

[Maciej S. Szmigiero]

Convert the late loader in the AMD microcode update driver to use newly
introduced microcode container data checking functions as it was previously
done for the early loader.

Signed-off-by: Maciej S. Szmigiero 
---
 arch/x86/kernel/cpu/microcode/amd.c | 70 +
 1 file changed, 32 insertions(+), 38 deletions(-)

diff --git a/arch/x86/kernel/cpu/microcode/amd.c 
b/arch/x86/kernel/cpu/microcode/amd.c
index f8bd74341ed8..3e10a5920f58 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -693,28 +693,26 @@ static enum ucode_state apply_microcode_amd(int cpu)
return UCODE_UPDATED;
 }
 
-static int install_equiv_cpu_table(const u8 *buf)
+static unsigned int install_equiv_cpu_table(const u8 *buf, size_t buf_size)
 {
-   unsigned int *ibuf = (unsigned int *)buf;
-   unsigned int type = ibuf[1];
-   unsigned int size = ibuf[2];
+   const u32 *hdr;
+   u32 equiv_tbl_len;
 
-   if (type != UCODE_EQUIV_CPU_TABLE_TYPE || !size) {
-   pr_err("empty section/"
-  "invalid type field in container file section header\n");
-   return -EINVAL;
-   }
+   if (!verify_equivalence_table(buf, buf_size, false))
+   return 0;
+
+   hdr = (const u32 *)buf;
+   equiv_tbl_len = hdr[2];
 
-   equiv_cpu_table = vmalloc(size);
+   equiv_cpu_table = vmalloc(equiv_tbl_len);
if (!equiv_cpu_table) {
pr_err("failed to allocate equivalent CPU table\n");
-   return -ENOMEM;
+   return 0;
}
 
-   memcpy(equiv_cpu_table, buf + CONTAINER_HDR_SZ, size);
+   memcpy(equiv_cpu_table, buf + CONTAINER_HDR_SZ, equiv_tbl_len);
 
-   /* add header length */
-   return size + CONTAINER_HDR_SZ;
+   return equiv_tbl_len;
 }
 
 static void free_equiv_cpu_table(void)
@@ -739,13 +737,19 @@ static void cleanup(void)
 static int verify_and_add_patch(u8 family, u8 *fw, unsigned int leftover,
unsigned int *crnt_size)
 {
+   u32 *hdr = (u32 *)fw;
struct microcode_header_amd *mc_hdr;
struct ucode_patch *patch;
-   unsigned int patch_size, ret;
+   u32 patch_size;
u32 proc_fam;
u16 proc_id;
 
-   patch_size  = *(u32 *)(fw + 4);
+   if (!verify_patch_section(fw, leftover, false)) {
+   *crnt_size = leftover;
+   return 0;
+   }
+
+   patch_size  = hdr[1];
*crnt_size  = patch_size + SECTION_HDR_SIZE;
mc_hdr  = (struct microcode_header_amd *)(fw + SECTION_HDR_SIZE);
proc_id = mc_hdr->processor_rev_id;
@@ -767,16 +771,8 @@ static int verify_and_add_patch(u8 family, u8 *fw, 
unsigned int leftover,
return 0;
}
 
-   /*
-* The section header length is not included in this indicated size
-* but is present in the leftover file length so we need to subtract
-* it before passing this value to the function below.
-*/
-   ret = verify_patch_size(family, patch_size, leftover - 
SECTION_HDR_SIZE);
-   if (!ret) {
-   pr_err("Patch-ID 0x%08x: size mismatch.\n", mc_hdr->patch_id);
+   if (!verify_patch(family, fw, leftover, false))
return 0;
-   }
 
patch = kzalloc(sizeof(*patch), GFP_KERNEL);
if (!patch) {
@@ -810,21 +806,21 @@ static enum ucode_state __load_microcode_amd(u8 family, 
const u8 *data,
enum ucode_state ret = UCODE_ERROR;
unsigned int leftover;
u8 *fw = (u8 *)data;
-   int offset;
+   unsigned int offset;
 
-   offset = install_equiv_cpu_table(data);
-   if (offset < 0) {
+   offset = install_equiv_cpu_table(data, size);
+   if (!offset) {
pr_err("failed to create equivalent cpu table\n");
return ret;
}
-   fw += offset;
-   leftover = size - offset;
 
-   if (*(u32 *)fw != UCODE_UCODE_TYPE) {
-   pr_err("invalid type field in container file section header\n");
-   free_equiv_cpu_table();
-   return ret;
-   }
+   /*
+* Skip also the container header, since install_equiv_cpu_table()
+* returns just the raw equivalence table size without the header.
+*/
+   fw += CONTAINER_HDR_SZ;
+   fw += offset;
+   leftover = size - CONTAINER_HDR_SZ - offset;
 
while (leftover) {
unsigned int crnt_size;
@@ -912,10 +908,8 @@ static enum ucode_state request_microcode_amd(int cpu, 
struct device *device,
}
 
ret = UCODE_ERROR;
-   if (*(u32 *)fw->data != UCODE_MAGIC) {
-   pr_err("invalid magic value (0x%08x)\n", *(u32 *)fw->data);
+   if (!verify_container(fw->data, fw->size, false))
goto fw_release;
-   }
 
ret = load_microcode_amd(bsp, c->x86, fw->data, fw->size);
 

[PATCH v6 5/8] x86/microcode/AMD: Check microcode container data in the late loader

[Maciej S. Szmigiero]

Convert the late loader in the AMD microcode update driver to use newly
introduced microcode container data checking functions as it was previously
done for the early loader.

Signed-off-by: Maciej S. Szmigiero 
---
 arch/x86/kernel/cpu/microcode/amd.c | 70 +
 1 file changed, 32 insertions(+), 38 deletions(-)

diff --git a/arch/x86/kernel/cpu/microcode/amd.c 
b/arch/x86/kernel/cpu/microcode/amd.c
index f8bd74341ed8..3e10a5920f58 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -693,28 +693,26 @@ static enum ucode_state apply_microcode_amd(int cpu)
return UCODE_UPDATED;
 }
 
-static int install_equiv_cpu_table(const u8 *buf)
+static unsigned int install_equiv_cpu_table(const u8 *buf, size_t buf_size)
 {
-   unsigned int *ibuf = (unsigned int *)buf;
-   unsigned int type = ibuf[1];
-   unsigned int size = ibuf[2];
+   const u32 *hdr;
+   u32 equiv_tbl_len;
 
-   if (type != UCODE_EQUIV_CPU_TABLE_TYPE || !size) {
-   pr_err("empty section/"
-  "invalid type field in container file section header\n");
-   return -EINVAL;
-   }
+   if (!verify_equivalence_table(buf, buf_size, false))
+   return 0;
+
+   hdr = (const u32 *)buf;
+   equiv_tbl_len = hdr[2];
 
-   equiv_cpu_table = vmalloc(size);
+   equiv_cpu_table = vmalloc(equiv_tbl_len);
if (!equiv_cpu_table) {
pr_err("failed to allocate equivalent CPU table\n");
-   return -ENOMEM;
+   return 0;
}
 
-   memcpy(equiv_cpu_table, buf + CONTAINER_HDR_SZ, size);
+   memcpy(equiv_cpu_table, buf + CONTAINER_HDR_SZ, equiv_tbl_len);
 
-   /* add header length */
-   return size + CONTAINER_HDR_SZ;
+   return equiv_tbl_len;
 }
 
 static void free_equiv_cpu_table(void)
@@ -739,13 +737,19 @@ static void cleanup(void)
 static int verify_and_add_patch(u8 family, u8 *fw, unsigned int leftover,
unsigned int *crnt_size)
 {
+   u32 *hdr = (u32 *)fw;
struct microcode_header_amd *mc_hdr;
struct ucode_patch *patch;
-   unsigned int patch_size, ret;
+   u32 patch_size;
u32 proc_fam;
u16 proc_id;
 
-   patch_size  = *(u32 *)(fw + 4);
+   if (!verify_patch_section(fw, leftover, false)) {
+   *crnt_size = leftover;
+   return 0;
+   }
+
+   patch_size  = hdr[1];
*crnt_size  = patch_size + SECTION_HDR_SIZE;
mc_hdr  = (struct microcode_header_amd *)(fw + SECTION_HDR_SIZE);
proc_id = mc_hdr->processor_rev_id;
@@ -767,16 +771,8 @@ static int verify_and_add_patch(u8 family, u8 *fw, 
unsigned int leftover,
return 0;
}
 
-   /*
-* The section header length is not included in this indicated size
-* but is present in the leftover file length so we need to subtract
-* it before passing this value to the function below.
-*/
-   ret = verify_patch_size(family, patch_size, leftover - 
SECTION_HDR_SIZE);
-   if (!ret) {
-   pr_err("Patch-ID 0x%08x: size mismatch.\n", mc_hdr->patch_id);
+   if (!verify_patch(family, fw, leftover, false))
return 0;
-   }
 
patch = kzalloc(sizeof(*patch), GFP_KERNEL);
if (!patch) {
@@ -810,21 +806,21 @@ static enum ucode_state __load_microcode_amd(u8 family, 
const u8 *data,
enum ucode_state ret = UCODE_ERROR;
unsigned int leftover;
u8 *fw = (u8 *)data;
-   int offset;
+   unsigned int offset;
 
-   offset = install_equiv_cpu_table(data);
-   if (offset < 0) {
+   offset = install_equiv_cpu_table(data, size);
+   if (!offset) {
pr_err("failed to create equivalent cpu table\n");
return ret;
}
-   fw += offset;
-   leftover = size - offset;
 
-   if (*(u32 *)fw != UCODE_UCODE_TYPE) {
-   pr_err("invalid type field in container file section header\n");
-   free_equiv_cpu_table();
-   return ret;
-   }
+   /*
+* Skip also the container header, since install_equiv_cpu_table()
+* returns just the raw equivalence table size without the header.
+*/
+   fw += CONTAINER_HDR_SZ;
+   fw += offset;
+   leftover = size - CONTAINER_HDR_SZ - offset;
 
while (leftover) {
unsigned int crnt_size;
@@ -912,10 +908,8 @@ static enum ucode_state request_microcode_amd(int cpu, 
struct device *device,
}
 
ret = UCODE_ERROR;
-   if (*(u32 *)fw->data != UCODE_MAGIC) {
-   pr_err("invalid magic value (0x%08x)\n", *(u32 *)fw->data);
+   if (!verify_container(fw->data, fw->size, false))
goto fw_release;
-   }
 
ret = load_microcode_amd(bsp, c->x86, fw->data, fw->size);