linux-kernel - [PATCH v7 6/9] x86/microcode/AMD: Check microcode container data in the late loader

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Date:   Tue, 19 Jun 2018 20:47:36 +0200
From:   "Maciej S. Szmigiero" <mail@...iej.szmigiero.name>
To:     Borislav Petkov <bp@...en8.de>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v7 6/9] x86/microcode/AMD: Check microcode container data in the late loader

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 <mail@...iej.szmigiero.name>
---
 arch/x86/kernel/cpu/microcode/amd.c | 67 +++++++++++++----------------
 1 file changed, 30 insertions(+), 37 deletions(-)

diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
index 9e29374ce4d0..2dbdd7951475 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -717,28 +717,26 @@ 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)
@@ -763,14 +761,18 @@ static void cleanup(void)
 static int verify_and_add_patch(u8 family, u8 *fw, unsigned int leftover,
 				unsigned int *crnt_size)
 {
+	const u32 *hdr;
 	struct microcode_header_amd *mc_hdr;
 	struct ucode_patch *patch;
-	unsigned int patch_size;
+	u32 patch_size;
 	u32 proc_fam;
 	u16 proc_id;
 
-	patch_size  = *(u32 *)(fw + 4);
-	*crnt_size  = patch_size + SECTION_HDR_SIZE;
+	if (!verify_patch(family, fw, leftover, crnt_size, false))
+		return 0;
+
+	hdr = (const u32 *)fw;
+	patch_size  = hdr[1];
 	mc_hdr	    = (struct microcode_header_amd *)(fw + SECTION_HDR_SIZE);
 	proc_id	    = mc_hdr->processor_rev_id;
 
@@ -791,11 +793,6 @@ static int verify_and_add_patch(u8 family, u8 *fw, unsigned int leftover,
 		return 0;
 	}
 
-	if (!verify_patch(family, fw, leftover, crnt_size, false)) {
-		pr_err("Patch-ID 0x%08x: size mismatch.\n", mc_hdr->patch_id);
-		return 0;
-	}
-
 	patch = kzalloc(sizeof(*patch), GFP_KERNEL);
 	if (!patch) {
 		pr_err("Patch allocation failure.\n");
@@ -828,21 +825,19 @@ 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) {
-		pr_err("failed to create equivalent cpu table\n");
+	offset = install_equiv_cpu_table(data, size);
+	if (!offset)
 		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;
@@ -930,10 +925,8 @@ 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);