Messages in this thread Patch in this message | | | Date | Mon, 30 Apr 2018 11:05:27 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH v5 4/6] x86/microcode/AMD: Check microcode container data in the late loader |
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On Mon, Apr 23, 2018 at 11:34:09PM +0200, Maciej S. Szmigiero wrote: > This commit converts the late loader in the AMD microcode update driver to > use newly introduced microcode container data checking functions as the > previous commit did for the early loader. > > Signed-off-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name> > --- > arch/x86/kernel/cpu/microcode/amd.c | 87 +++++++++++++++++-------------------- > 1 file changed, 40 insertions(+), 47 deletions(-) > > diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c > index 94fcd702a67a..b429d3f554b9 100644 > --- a/arch/x86/kernel/cpu/microcode/amd.c > +++ b/arch/x86/kernel/cpu/microcode/amd.c > @@ -677,28 +677,24 @@ 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 = (const u32 *)buf;
Ok, since we're verifying now, let's do that assignment...
> + 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;
... after the check has passed.
> - equiv_cpu_table = vmalloc(size); > + equiv_tbl_len = hdr[2];
<---- newline here.
> + 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) > @@ -715,20 +711,26 @@ static void cleanup(void) > > /* > * We return the current size even if some of the checks failed so that > - * we can skip over the next patch. If we return a negative value, we > - * signal a grave error like a memory allocation has failed and the > - * driver cannot continue functioning normally. In such cases, we tear > - * down everything we've used up so far and exit. > + * we can skip over the next patch. If we return zero, we signal a > + * grave error like a memory allocation has failed and the driver cannot > + * continue functioning normally. In such cases, we tear down everything > + * we've used up so far and exit. > */ > -static int verify_and_add_patch(u8 family, u8 *fw, unsigned int leftover) > +static unsigned int verify_and_add_patch(u8 family, u8 *fw, > + unsigned int leftover) > { > + u32 *hdr = (u32 *)fw; > struct microcode_header_amd *mc_hdr; > struct ucode_patch *patch; > - unsigned int patch_size, crnt_size, ret; > + u32 patch_size; > + unsigned int crnt_size; > u32 proc_fam; > u16 proc_id; > > - patch_size = *(u32 *)(fw + 4); > + if (!verify_patch_section(fw, leftover, false)) > + return leftover; > + > + 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; > @@ -750,28 +752,20 @@ static int verify_and_add_patch(u8 family, u8 *fw, unsigned int leftover) > return crnt_size; > } > > - /* > - * 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 crnt_size; > - } > > patch = kzalloc(sizeof(*patch), GFP_KERNEL); > if (!patch) { > pr_err("Patch allocation failure.\n"); > - return -EINVAL; > + return 0;
So by convention returning 0 is success and negative value means error. I don't see the reason for changing that in the whole code.
> } > > patch->data = kmemdup(fw + SECTION_HDR_SIZE, patch_size, GFP_KERNEL); > if (!patch->data) { > pr_err("Patch data allocation failure.\n"); > kfree(patch); > - return -EINVAL; > + return 0; > } > > INIT_LIST_HEAD(&patch->plist); > @@ -793,26 +787,27 @@ 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 crnt_size = 0; > - 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; > + > crnt_size = verify_and_add_patch(family, fw, leftover); > - if (crnt_size < 0) > + if (!crnt_size)
Ditto.
> return ret; > > fw += crnt_size; > @@ -895,10 +890,8 @@ 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); >
-- Regards/Gruss, Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
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