Merge tag 'chrome-platform-firmware-v7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/chrome-platform/linuxHEADmaster

Pull chrome platform firmware updates from Tzung-Bi Shih:
 "Fixes:
    - Don't map no-map memory regions for CBMEM entries
    - Check bound of coreboot table entries

  Cleanups:
  - Fix typo in docs"

* tag 'chrome-platform-firmware-v7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/chrome-platform/linux:
  firmware: coreboot: Validate table bounds
  firmware: coreboot: Skip no-map CBMEM entries
  docs: ABI: testing: Fix typo

2 files changed, 37 insertions, 8 deletions

diff --git a/Documentation/ABI/testing/sysfs-firmware-gsmi b/Documentation/ABI/testing/sysfs-firmware-gsmi
index 7a558354c1ee..3b3c3ae6f458 100644
--- a/Documentation/ABI/testing/sysfs-firmware-gsmi
+++ b/Documentation/ABI/testing/sysfs-firmware-gsmi
@@ -19,7 +19,7 @@ Description:
 		/sys/firmware/gsmi/vars:
 
 			This directory has the same layout (and
-			underlying implementation as /sys/firmware/efi/vars.
+			underlying implementation) as /sys/firmware/efi/vars.
 			See `Documentation/ABI/*/sysfs-firmware-efi-vars`
 			for more information on how to interact with
 			this structure.
diff --git a/drivers/firmware/google/coreboot_table.c b/drivers/firmware/google/coreboot_table.c
index e63933ff6747..25ee8cf53429 100644
--- a/drivers/firmware/google/coreboot_table.c
+++ b/drivers/firmware/google/coreboot_table.c
@@ -13,8 +13,10 @@
 #include <linux/err.h>
 #include <linux/init.h>
 #include <linux/io.h>
+#include <linux/ioport.h>
 #include <linux/kernel.h>
 #include <linux/device-id/coreboot.h>
+#include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
@@ -123,7 +125,7 @@ static int coreboot_table_populate(struct device *dev, void *ptr, resource_size_
 
 	ptr_end = ptr + len;
 	ptr_entry = ptr + header->header_bytes;
-	for (i = 0; i < header->table_entries; i++) {
+	for (i = 0; i < header->table_entries; i++, ptr_entry += entry->size) {
 		if (ptr_entry + sizeof(*entry) > ptr_end)
 			return -EINVAL;
 		entry = ptr_entry;
@@ -147,6 +149,26 @@ static int coreboot_table_populate(struct device *dev, void *ptr, resource_size_
 
 		switch (device->entry.tag) {
 		case LB_TAG_CBMEM_ENTRY:
+			/*
+			 * Skip entries that are not exclusively System RAM or
+			 * Reserved memory.
+			 * On ARM64, no-map regions are filtered out as they are
+			 * IORESOURCE_MEM (see request_standard_resources() in
+			 * arch/arm64/kernel/setup.c).
+			 * On x86, CBMEM often resides in standard reserved regions
+			 * (IORES_DESC_RESERVED).
+			 */
+			if (region_intersects(device->cbmem_entry.address,
+					      device->cbmem_entry.entry_size,
+					      IORESOURCE_SYSTEM_RAM,
+					      IORES_DESC_NONE) != REGION_INTERSECTS &&
+			    region_intersects(device->cbmem_entry.address,
+					      device->cbmem_entry.entry_size,
+					      IORESOURCE_MEM,
+					      IORES_DESC_RESERVED) != REGION_INTERSECTS) {
+				kfree(device);
+				continue;
+			}
 			dev_set_name(&device->dev, "cbmem-%08x",
 				     device->cbmem_entry.id);
 			break;
@@ -155,8 +177,6 @@ static int coreboot_table_populate(struct device *dev, void *ptr, resource_size_
 			break;
 		}
 
-		ptr_entry += entry->size;
-
 		ret = device_register(&device->dev);
 		if (ret) {
 			dev_warn(dev, "failed to register coreboot device: %d\n", ret);
@@ -170,6 +190,7 @@ static int coreboot_table_populate(struct device *dev, void *ptr, resource_size_
 static int coreboot_table_probe(struct platform_device *pdev)
 {
 	resource_size_t len;
+	resource_size_t table_span;
 	struct coreboot_table_header *header;
 	struct resource *res;
 	struct device *dev = &pdev->dev;
@@ -181,7 +202,7 @@ static int coreboot_table_probe(struct platform_device *pdev)
 		return -EINVAL;
 
 	len = resource_size(res);
-	if (!res->start || !len)
+	if (!res->start || len < sizeof(*header))
 		return -EINVAL;
 
 	/* Check just the header first to make sure things are sane */
@@ -189,19 +210,27 @@ static int coreboot_table_probe(struct platform_device *pdev)
 	if (!header)
 		return -ENOMEM;
 
-	len = header->header_bytes + header->table_bytes;
 	ret = strncmp(header->signature, "LBIO", sizeof(header->signature));
+
+	if (!ret &&
+	    (header->header_bytes < sizeof(*header) ||
+	     check_add_overflow((resource_size_t)header->header_bytes,
+				(resource_size_t)header->table_bytes,
+				&table_span) ||
+	     table_span > len))
+		ret = -EINVAL;
+
 	memunmap(header);
 	if (ret) {
 		dev_warn(dev, "coreboot table missing or corrupt!\n");
 		return -ENODEV;
 	}
 
-	ptr = memremap(res->start, len, MEMREMAP_WB);
+	ptr = memremap(res->start, table_span, MEMREMAP_WB);
 	if (!ptr)
 		return -ENOMEM;
 
-	ret = coreboot_table_populate(dev, ptr, len);
+	ret = coreboot_table_populate(dev, ptr, table_span);
 
 	memunmap(ptr);