x86, microcode, AMD: Extend ucode size verification

Upstream commit: 44d60c0f

The different families have a different max size for the ucode patch,
adjust size checking to the family we're running on. Also, do not
vzalloc the max size of the ucode but only the actual size that is
passed on from the firmware loader.

Cc: <stable@kernel.org>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

arch/x86/kernel/microcode_amd.c

@@ -63,7 +63,6 @@ struct microcode_amd {
 	unsigned int			mpb[0];
 };
 
-#define UCODE_MAX_SIZE			2048
 #define UCODE_CONTAINER_SECTION_HDR	8
 #define UCODE_CONTAINER_HEADER_SIZE	12
 
@@ -125,6 +124,37 @@ static int get_matching_microcode(int cpu, void *mc, int rev)
 	return 1;
 }
 
+static unsigned int verify_ucode_size(int cpu, const u8 *buf, unsigned int size)
+{
+	struct cpuinfo_x86 *c = &cpu_data(cpu);
+	unsigned int max_size, actual_size;
+
+#define F1XH_MPB_MAX_SIZE 2048
+#define F14H_MPB_MAX_SIZE 1824
+#define F15H_MPB_MAX_SIZE 4096
+
+	switch (c->x86) {
+	case 0x14:
+		max_size = F14H_MPB_MAX_SIZE;
+		break;
+	case 0x15:
+		max_size = F15H_MPB_MAX_SIZE;
+		break;
+	default:
+		max_size = F1XH_MPB_MAX_SIZE;
+		break;
+	}
+
+	actual_size = buf[4] + (buf[5] << 8);
+
+	if (actual_size > size || actual_size > max_size) {
+		pr_err("section size mismatch\n");
+		return 0;
+	}
+
+	return actual_size;
+}
+
 static int apply_microcode_amd(int cpu)
 {
 	u32 rev, dummy;
@@ -164,11 +194,11 @@ static int get_ucode_data(void *to, const u8 *from, size_t n)
 }
 
 static void *
-get_next_ucode(const u8 *buf, unsigned int size, unsigned int *mc_size)
+get_next_ucode(int cpu, const u8 *buf, unsigned int size, unsigned int *mc_size)
 {
-	unsigned int total_size;
+	unsigned int actual_size = 0;
 	u8 section_hdr[UCODE_CONTAINER_SECTION_HDR];
-	void *mc;
+	void *mc = NULL;
 
 	if (get_ucode_data(section_hdr, buf, UCODE_CONTAINER_SECTION_HDR))
 		return NULL;
@@ -179,23 +209,18 @@ get_next_ucode(const u8 *buf, unsigned int size, unsigned int *mc_size)
 		return NULL;
 	}
 
-	total_size = (unsigned long) (section_hdr[4] + (section_hdr[5] << 8));
+	actual_size = verify_ucode_size(cpu, buf, size);
+	if (!actual_size)
+		return NULL;
 
-	if (total_size > size || total_size > UCODE_MAX_SIZE) {
-		printk(KERN_ERR "microcode: error: size mismatch\n");
+	mc = vmalloc(actual_size);
+	if (!mc)
 		return NULL;
-	}
 
-	mc = vmalloc(UCODE_MAX_SIZE);
-	if (mc) {
-		memset(mc, 0, UCODE_MAX_SIZE);
-		if (get_ucode_data(mc, buf + UCODE_CONTAINER_SECTION_HDR,
-				   total_size)) {
-			vfree(mc);
-			mc = NULL;
-		} else
-			*mc_size = total_size + UCODE_CONTAINER_SECTION_HDR;
-	}
+	memset(mc, 0, actual_size);
+	get_ucode_data(mc, buf + UCODE_CONTAINER_SECTION_HDR, actual_size);
+	*mc_size = actual_size + UCODE_CONTAINER_SECTION_HDR;
+
 	return mc;
 }
 
@@ -264,7 +289,7 @@ generic_load_microcode(int cpu, const u8 *data, size_t size)
 		unsigned int uninitialized_var(mc_size);
 		struct microcode_header_amd *mc_header;
 
-		mc = get_next_ucode(ucode_ptr, leftover, &mc_size);
+		mc = get_next_ucode(cpu, ucode_ptr, leftover, &mc_size);
 		if (!mc)
 			break;