Merge branch 'x86-microcode-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 microcode loading updates from Borislav Petkov:
 "This update contains work started by Maciej to make the microcode
  container verification more robust against all kinds of corruption and
  also unify verification paths between early and late loading.

  The result is a set of verification routines which validate the
  microcode blobs before loading it on the CPU. In addition, the code is
  a lot more streamlined and unified.

  In the process, some of the aspects of patch handling and loading were
  simplified.

  All provided by Maciej S. Szmigiero and Borislav Petkov"

* 'x86-microcode-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/microcode/AMD: Update copyright
  x86/microcode/AMD: Check the equivalence table size when scanning it
  x86/microcode/AMD: Convert CPU equivalence table variable into a struct
  x86/microcode/AMD: Check microcode container data in the late loader
  x86/microcode/AMD: Fix container size's type
  x86/microcode/AMD: Convert early parser to the new verification routines
  x86/microcode/AMD: Change verify_patch()'s return value
  x86/microcode/AMD: Move chipset-specific check into verify_patch()
  x86/microcode/AMD: Move patch family check to verify_patch()
  x86/microcode/AMD: Simplify patch family detection
  x86/microcode/AMD: Concentrate patch verification
  x86/microcode/AMD: Cleanup verify_patch_size() more
  x86/microcode/AMD: Clean up per-family patch size checks
  x86/microcode/AMD: Move verify_patch_size() up in the file
  x86/microcode/AMD: Add microcode container verification
  x86/microcode/AMD: Subtract SECTION_HDR_SIZE from file leftover length

1 files changed, 308 insertions, 162 deletions

diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
index 07b5fc00b188..51adde0a0f1a 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -5,7 +5,7 @@
  *  CPUs and later.
  *
  *  Copyright (C) 2008-2011 Advanced Micro Devices Inc.
- *	          2013-2016 Borislav Petkov <bp@alien8.de>
+ *	          2013-2018 Borislav Petkov <bp@alien8.de>
  *
  *  Author: Peter Oruba <peter.oruba@amd.com>
  *
@@ -38,7 +38,10 @@
 #include <asm/cpu.h>
 #include <asm/msr.h>
 
-static struct equiv_cpu_entry *equiv_cpu_table;
+static struct equiv_cpu_table {
+	unsigned int num_entries;
+	struct equiv_cpu_entry *entry;
+} equiv_table;
 
 /*
  * This points to the current valid container of microcode patches which we will
@@ -63,13 +66,225 @@ static u8 amd_ucode_patch[PATCH_MAX_SIZE];
 static const char
 ucode_path[] __maybe_unused = "kernel/x86/microcode/AuthenticAMD.bin";
 
-static u16 find_equiv_id(struct equiv_cpu_entry *equiv_table, u32 sig)
+static u16 find_equiv_id(struct equiv_cpu_table *et, u32 sig)
 {
-	for (; equiv_table && equiv_table->installed_cpu; equiv_table++) {
-		if (sig == equiv_table->installed_cpu)
-			return equiv_table->equiv_cpu;
+	unsigned int i;
+
+	if (!et || !et->num_entries)
+		return 0;
+
+	for (i = 0; i < et->num_entries; i++) {
+		struct equiv_cpu_entry *e = &et->entry[i];
+
+		if (sig == e->installed_cpu)
+			return e->equiv_cpu;
+
+		e++;
+	}
+	return 0;
+}
+
+/*
+ * Check whether there is a valid microcode container file at the beginning
+ * of @buf of size @buf_size. Set @early to use this function in the early path.
+ */
+static bool verify_container(const u8 *buf, size_t buf_size, bool early)
+{
+	u32 cont_magic;
+
+	if (buf_size <= CONTAINER_HDR_SZ) {
+		if (!early)
+			pr_debug("Truncated microcode container header.\n");
+
+		return false;
+	}
+
+	cont_magic = *(const u32 *)buf;
+	if (cont_magic != UCODE_MAGIC) {
+		if (!early)
+			pr_debug("Invalid magic value (0x%08x).\n", cont_magic);
+
+		return false;
+	}
+
+	return true;
+}
+
+/*
+ * Check whether there is a valid, non-truncated CPU equivalence table at the
+ * beginning of @buf of size @buf_size. Set @early to use this function in the
+ * early path.
+ */
+static bool verify_equivalence_table(const u8 *buf, size_t buf_size, bool early)
+{
+	const u32 *hdr = (const u32 *)buf;
+	u32 cont_type, equiv_tbl_len;
+
+	if (!verify_container(buf, buf_size, early))
+		return false;
+
+	cont_type = hdr[1];
+	if (cont_type != UCODE_EQUIV_CPU_TABLE_TYPE) {
+		if (!early)
+			pr_debug("Wrong microcode container equivalence table type: %u.\n",
+			       cont_type);
+
+		return false;
+	}
+
+	buf_size -= CONTAINER_HDR_SZ;
+
+	equiv_tbl_len = hdr[2];
+	if (equiv_tbl_len < sizeof(struct equiv_cpu_entry) ||
+	    buf_size < equiv_tbl_len) {
+		if (!early)
+			pr_debug("Truncated equivalence table.\n");
+
+		return false;
+	}
+
+	return true;
+}
+
+/*
+ * Check whether there is a valid, non-truncated microcode patch section at the
+ * beginning of @buf of size @buf_size. Set @early to use this function in the
+ * early path.
+ *
+ * On success, @sh_psize returns the patch size according to the section header,
+ * to the caller.
+ */
+static bool
+__verify_patch_section(const u8 *buf, size_t buf_size, u32 *sh_psize, bool early)
+{
+	u32 p_type, p_size;
+	const u32 *hdr;
+
+	if (buf_size < SECTION_HDR_SIZE) {
+		if (!early)
+			pr_debug("Truncated patch section.\n");
+
+		return false;
+	}
+
+	hdr = (const u32 *)buf;
+	p_type = hdr[0];
+	p_size = hdr[1];
+
+	if (p_type != UCODE_UCODE_TYPE) {
+		if (!early)
+			pr_debug("Invalid type field (0x%x) in container file section header.\n",
+				p_type);
+
+		return false;
+	}
+
+	if (p_size < sizeof(struct microcode_header_amd)) {
+		if (!early)
+			pr_debug("Patch of size %u too short.\n", p_size);
+
+		return false;
+	}
+
+	*sh_psize = p_size;
+
+	return true;
+}
+
+/*
+ * Check whether the passed remaining file @buf_size is large enough to contain
+ * a patch of the indicated @sh_psize (and also whether this size does not
+ * exceed the per-family maximum). @sh_psize is the size read from the section
+ * header.
+ */
+static unsigned int __verify_patch_size(u8 family, u32 sh_psize, size_t buf_size)
+{
+	u32 max_size;
+
+	if (family >= 0x15)
+		return min_t(u32, sh_psize, buf_size);
+
+#define F1XH_MPB_MAX_SIZE 2048
+#define F14H_MPB_MAX_SIZE 1824
+
+	switch (family) {
+	case 0x10 ... 0x12:
+		max_size = F1XH_MPB_MAX_SIZE;
+		break;
+	case 0x14:
+		max_size = F14H_MPB_MAX_SIZE;
+		break;
+	default:
+		WARN(1, "%s: WTF family: 0x%x\n", __func__, family);
+		return 0;
+		break;
+	}
+
+	if (sh_psize > min_t(u32, buf_size, max_size))
+		return 0;
+
+	return sh_psize;
+}
+
+/*
+ * Verify the patch in @buf.
+ *
+ * Returns:
+ * negative: on error
+ * positive: patch is not for this family, skip it
+ * 0: success
+ */
+static int
+verify_patch(u8 family, const u8 *buf, size_t buf_size, u32 *patch_size, bool early)
+{
+	struct microcode_header_amd *mc_hdr;
+	unsigned int ret;
+	u32 sh_psize;
+	u16 proc_id;
+	u8 patch_fam;
+
+	if (!__verify_patch_section(buf, buf_size, &sh_psize, early))
+		return -1;
+
+	/*
+	 * 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.
+	 */
+	buf_size -= SECTION_HDR_SIZE;
+
+	/*
+	 * Check if the remaining buffer is big enough to contain a patch of
+	 * size sh_psize, as the section claims.
+	 */
+	if (buf_size < sh_psize) {
+		if (!early)
+			pr_debug("Patch of size %u truncated.\n", sh_psize);
+
+		return -1;
+	}
+
+	ret = __verify_patch_size(family, sh_psize, buf_size);
+	if (!ret) {
+		if (!early)
+			pr_debug("Per-family patch size mismatch.\n");
+		return -1;
+	}
+
+	*patch_size = sh_psize;
+
+	mc_hdr	= (struct microcode_header_amd *)(buf + SECTION_HDR_SIZE);
+	if (mc_hdr->nb_dev_id || mc_hdr->sb_dev_id) {
+		if (!early)
+			pr_err("Patch-ID 0x%08x: chipset-specific code unsupported.\n", mc_hdr->patch_id);
+		return -1;
 	}
 
+	proc_id	= mc_hdr->processor_rev_id;
+	patch_fam = 0xf + (proc_id >> 12);
+	if (patch_fam != family)
+		return 1;
+
 	return 0;
 }
 
@@ -80,26 +295,28 @@ static u16 find_equiv_id(struct equiv_cpu_entry *equiv_table, u32 sig)
  * Returns the amount of bytes consumed while scanning. @desc contains all the
  * data we're going to use in later stages of the application.
  */
-static ssize_t parse_container(u8 *ucode, ssize_t size, struct cont_desc *desc)
+static size_t parse_container(u8 *ucode, size_t size, struct cont_desc *desc)
 {
-	struct equiv_cpu_entry *eq;
-	ssize_t orig_size = size;
+	struct equiv_cpu_table table;
+	size_t orig_size = size;
 	u32 *hdr = (u32 *)ucode;
 	u16 eq_id;
 	u8 *buf;
 
-	/* Am I looking at an equivalence table header? */
-	if (hdr[0] != UCODE_MAGIC ||
-	    hdr[1] != UCODE_EQUIV_CPU_TABLE_TYPE ||
-	    hdr[2] == 0)
-		return CONTAINER_HDR_SZ;
+	if (!verify_equivalence_table(ucode, size, true))
+		return 0;
 
 	buf = ucode;
 
-	eq = (struct equiv_cpu_entry *)(buf + CONTAINER_HDR_SZ);
+	table.entry = (struct equiv_cpu_entry *)(buf + CONTAINER_HDR_SZ);
+	table.num_entries = hdr[2] / sizeof(struct equiv_cpu_entry);
 
-	/* Find the equivalence ID of our CPU in this table: */
-	eq_id = find_equiv_id(eq, desc->cpuid_1_eax);
+	/*
+	 * Find the equivalence ID of our CPU in this table. Even if this table
+	 * doesn't contain a patch for the CPU, scan through the whole container
+	 * so that it can be skipped in case there are other containers appended.
+	 */
+	eq_id = find_equiv_id(&table, desc->cpuid_1_eax);
 
 	buf  += hdr[2] + CONTAINER_HDR_SZ;
 	size -= hdr[2] + CONTAINER_HDR_SZ;
@@ -111,29 +328,29 @@ static ssize_t parse_container(u8 *ucode, ssize_t size, struct cont_desc *desc)
 	while (size > 0) {
 		struct microcode_amd *mc;
 		u32 patch_size;
+		int ret;
+
+		ret = verify_patch(x86_family(desc->cpuid_1_eax), buf, size, &patch_size, true);
+		if (ret < 0) {
+			/*
+			 * Patch verification failed, skip to the next
+			 * container, if there's one:
+			 */
+			goto out;
+		} else if (ret > 0) {
+			goto skip;
+		}
 
-		hdr = (u32 *)buf;
-
-		if (hdr[0] != UCODE_UCODE_TYPE)
-			break;
-
-		/* Sanity-check patch size. */
-		patch_size = hdr[1];
-		if (patch_size > PATCH_MAX_SIZE)
-			break;
-
-		/* Skip patch section header: */
-		buf  += SECTION_HDR_SIZE;
-		size -= SECTION_HDR_SIZE;
-
-		mc = (struct microcode_amd *)buf;
+		mc = (struct microcode_amd *)(buf + SECTION_HDR_SIZE);
 		if (eq_id == mc->hdr.processor_rev_id) {
 			desc->psize = patch_size;
 			desc->mc = mc;
 		}
 
-		buf  += patch_size;
-		size -= patch_size;
+skip:
+		/* Skip patch section header too: */
+		buf  += patch_size + SECTION_HDR_SIZE;
+		size -= patch_size + SECTION_HDR_SIZE;
 	}
 
 	/*
@@ -150,6 +367,7 @@ static ssize_t parse_container(u8 *ucode, ssize_t size, struct cont_desc *desc)
 		return 0;
 	}
 
+out:
 	return orig_size - size;
 }
 
@@ -159,15 +377,18 @@ static ssize_t parse_container(u8 *ucode, ssize_t size, struct cont_desc *desc)
  */
 static void scan_containers(u8 *ucode, size_t size, struct cont_desc *desc)
 {
-	ssize_t rem = size;
-
-	while (rem >= 0) {
-		ssize_t s = parse_container(ucode, rem, desc);
+	while (size) {
+		size_t s = parse_container(ucode, size, desc);
 		if (!s)
 			return;
 
-		ucode += s;
-		rem   -= s;
+		/* catch wraparound */
+		if (size >= s) {
+			ucode += s;
+			size  -= s;
+		} else {
+			return;
+		}
 	}
 }
 
@@ -364,21 +585,7 @@ void reload_ucode_amd(void)
 static u16 __find_equiv_id(unsigned int cpu)
 {
 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
-	return find_equiv_id(equiv_cpu_table, uci->cpu_sig.sig);
-}
-
-static u32 find_cpu_family_by_equiv_cpu(u16 equiv_cpu)
-{
-	int i = 0;
-
-	BUG_ON(!equiv_cpu_table);
-
-	while (equiv_cpu_table[i].equiv_cpu != 0) {
-		if (equiv_cpu == equiv_cpu_table[i].equiv_cpu)
-			return equiv_cpu_table[i].installed_cpu;
-		i++;
-	}
-	return 0;
+	return find_equiv_id(&equiv_table, uci->cpu_sig.sig);
 }
 
 /*
@@ -461,43 +668,6 @@ static int collect_cpu_info_amd(int cpu, struct cpu_signature *csig)
 	return 0;
 }
 
-static unsigned int verify_patch_size(u8 family, u32 patch_size,
-				      unsigned int size)
-{
-	u32 max_size;
-
-#define F1XH_MPB_MAX_SIZE 2048
-#define F14H_MPB_MAX_SIZE 1824
-#define F15H_MPB_MAX_SIZE 4096
-#define F16H_MPB_MAX_SIZE 3458
-#define F17H_MPB_MAX_SIZE 3200
-
-	switch (family) {
-	case 0x14:
-		max_size = F14H_MPB_MAX_SIZE;
-		break;
-	case 0x15:
-		max_size = F15H_MPB_MAX_SIZE;
-		break;
-	case 0x16:
-		max_size = F16H_MPB_MAX_SIZE;
-		break;
-	case 0x17:
-		max_size = F17H_MPB_MAX_SIZE;
-		break;
-	default:
-		max_size = F1XH_MPB_MAX_SIZE;
-		break;
-	}
-
-	if (patch_size > min_t(u32, size, max_size)) {
-		pr_err("patch size mismatch\n");
-		return 0;
-	}
-
-	return patch_size;
-}
-
 static enum ucode_state apply_microcode_amd(int cpu)
 {
 	struct cpuinfo_x86 *c = &cpu_data(cpu);
@@ -548,34 +718,34 @@ out:
 	return ret;
 }
 
-static int install_equiv_cpu_table(const u8 *buf)
+static size_t 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];
+	u32 equiv_tbl_len;
+	const u32 *hdr;
 
-	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);
-	if (!equiv_cpu_table) {
+	equiv_table.entry = vmalloc(equiv_tbl_len);
+	if (!equiv_table.entry) {
 		pr_err("failed to allocate equivalent CPU table\n");
-		return -ENOMEM;
+		return 0;
 	}
 
-	memcpy(equiv_cpu_table, buf + CONTAINER_HDR_SZ, size);
+	memcpy(equiv_table.entry, buf + CONTAINER_HDR_SZ, equiv_tbl_len);
+	equiv_table.num_entries = equiv_tbl_len / sizeof(struct equiv_cpu_entry);
 
 	/* add header length */
-	return size + CONTAINER_HDR_SZ;
+	return equiv_tbl_len + CONTAINER_HDR_SZ;
 }
 
 static void free_equiv_cpu_table(void)
 {
-	vfree(equiv_cpu_table);
-	equiv_cpu_table = NULL;
+	vfree(equiv_table.entry);
+	memset(&equiv_table, 0, sizeof(equiv_table));
 }
 
 static void cleanup(void)
@@ -585,47 +755,23 @@ static void cleanup(void)
 }
 
 /*
- * We return the current size even if some of the checks failed so that
+ * Return a non-negative value 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.
  */
-static int verify_and_add_patch(u8 family, u8 *fw, unsigned int leftover)
+static int verify_and_add_patch(u8 family, u8 *fw, unsigned int leftover,
+				unsigned int *patch_size)
 {
 	struct microcode_header_amd *mc_hdr;
 	struct ucode_patch *patch;
-	unsigned int patch_size, crnt_size, ret;
-	u32 proc_fam;
 	u16 proc_id;
+	int ret;
 
-	patch_size  = *(u32 *)(fw + 4);
-	crnt_size   = patch_size + SECTION_HDR_SIZE;
-	mc_hdr	    = (struct microcode_header_amd *)(fw + SECTION_HDR_SIZE);
-	proc_id	    = mc_hdr->processor_rev_id;
-
-	proc_fam = find_cpu_family_by_equiv_cpu(proc_id);
-	if (!proc_fam) {
-		pr_err("No patch family for equiv ID: 0x%04x\n", proc_id);
-		return crnt_size;
-	}
-
-	/* check if patch is for the current family */
-	proc_fam = ((proc_fam >> 8) & 0xf) + ((proc_fam >> 20) & 0xff);
-	if (proc_fam != family)
-		return crnt_size;
-
-	if (mc_hdr->nb_dev_id || mc_hdr->sb_dev_id) {
-		pr_err("Patch-ID 0x%08x: chipset-specific code unsupported.\n",
-			mc_hdr->patch_id);
-		return crnt_size;
-	}
-
-	ret = verify_patch_size(family, patch_size, leftover);
-	if (!ret) {
-		pr_err("Patch-ID 0x%08x: size mismatch.\n", mc_hdr->patch_id);
-		return crnt_size;
-	}
+	ret = verify_patch(family, fw, leftover, patch_size, false);
+	if (ret)
+		return ret;
 
 	patch = kzalloc(sizeof(*patch), GFP_KERNEL);
 	if (!patch) {
@@ -633,13 +779,16 @@ static int verify_and_add_patch(u8 family, u8 *fw, unsigned int leftover)
 		return -EINVAL;
 	}
 
-	patch->data = kmemdup(fw + SECTION_HDR_SIZE, patch_size, GFP_KERNEL);
+	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;
 	}
 
+	mc_hdr      = (struct microcode_header_amd *)(fw + SECTION_HDR_SIZE);
+	proc_id     = mc_hdr->processor_rev_id;
+
 	INIT_LIST_HEAD(&patch->plist);
 	patch->patch_id  = mc_hdr->patch_id;
 	patch->equiv_cpu = proc_id;
@@ -650,39 +799,38 @@ static int verify_and_add_patch(u8 family, u8 *fw, unsigned int leftover)
 	/* ... and add to cache. */
 	update_cache(patch);
 
-	return crnt_size;
+	return 0;
 }
 
 static enum ucode_state __load_microcode_amd(u8 family, const u8 *data,
 					     size_t size)
 {
-	enum ucode_state ret = UCODE_ERROR;
-	unsigned int leftover;
 	u8 *fw = (u8 *)data;
-	int crnt_size = 0;
-	int offset;
+	size_t offset;
 
-	offset = install_equiv_cpu_table(data);
-	if (offset < 0) {
-		pr_err("failed to create equivalent cpu table\n");
-		return ret;
-	}
-	fw += offset;
-	leftover = size - offset;
+	offset = install_equiv_cpu_table(data, size);
+	if (!offset)
+		return UCODE_ERROR;
+
+	fw   += offset;
+	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;
+		return UCODE_ERROR;
 	}
 
-	while (leftover) {
-		crnt_size = verify_and_add_patch(family, fw, leftover);
-		if (crnt_size < 0)
-			return ret;
+	while (size > 0) {
+		unsigned int crnt_size = 0;
+		int ret;
 
-		fw	 += crnt_size;
-		leftover -= crnt_size;
+		ret = verify_and_add_patch(family, fw, size, &crnt_size);
+		if (ret < 0)
+			return UCODE_ERROR;
+
+		fw   +=  crnt_size + SECTION_HDR_SIZE;
+		size -= (crnt_size + SECTION_HDR_SIZE);
 	}
 
 	return UCODE_OK;
@@ -761,10 +909,8 @@ 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);