@@ -944,6 +944,7 @@ static void __init __efi_enter_virtual_mode(void)
goto err;
}
+ efi_check_for_embedded_firmwares();
efi_free_boot_services();
/*
@@ -239,6 +239,11 @@ config EFI_DISABLE_PCI_DMA
endmenu
+config EFI_EMBEDDED_FIRMWARE
+ bool
+ depends on EFI
+ select CRYPTO_LIB_SHA256
+
config UEFI_CPER
bool
@@ -26,6 +26,7 @@ obj-$(CONFIG_EFI_TEST) += test/
obj-$(CONFIG_EFI_DEV_PATH_PARSER) += dev-path-parser.o
obj-$(CONFIG_APPLE_PROPERTIES) += apple-properties.o
obj-$(CONFIG_EFI_RCI2_TABLE) += rci2-table.o
+obj-$(CONFIG_EFI_EMBEDDED_FIRMWARE) += embedded-firmware.o
fake_map-y += fake_mem.o
fake_map-$(CONFIG_X86) += x86_fake_mem.o
new file mode 100644
@@ -0,0 +1,147 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Support for extracting embedded firmware for peripherals from EFI code,
+ *
+ * Copyright (c) 2018 Hans de Goede <hdegoede@redhat.com>
+ */
+
+#include <linux/dmi.h>
+#include <linux/efi.h>
+#include <linux/efi_embedded_fw.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/vmalloc.h>
+#include <crypto/sha.h>
+
+/* Exported for use by lib/test_firmware.c only */
+LIST_HEAD(efi_embedded_fw_list);
+EXPORT_SYMBOL_GPL(efi_embedded_fw_list);
+
+static bool checked_for_fw;
+
+static const struct dmi_system_id * const embedded_fw_table[] = {
+ NULL
+};
+
+/*
+ * Note the efi_check_for_embedded_firmwares() code currently makes the
+ * following 2 assumptions. This may needs to be revisited if embedded firmware
+ * is found where this is not true:
+ * 1) The firmware is only found in EFI_BOOT_SERVICES_CODE memory segments
+ * 2) The firmware always starts at an offset which is a multiple of 8 bytes
+ */
+static int __init efi_check_md_for_embedded_firmware(
+ efi_memory_desc_t *md, const struct efi_embedded_fw_desc *desc)
+{
+ struct sha256_state sctx;
+ struct efi_embedded_fw *fw;
+ u8 sha256[32];
+ u64 i, size;
+ u8 *map;
+
+ size = md->num_pages << EFI_PAGE_SHIFT;
+ map = memremap(md->phys_addr, size, MEMREMAP_WB);
+ if (!map) {
+ pr_err("Error mapping EFI mem at %#llx\n", md->phys_addr);
+ return -ENOMEM;
+ }
+
+ for (i = 0; (i + desc->length) <= size; i += 8) {
+ if (memcmp(map + i, desc->prefix, EFI_EMBEDDED_FW_PREFIX_LEN))
+ continue;
+
+ sha256_init(&sctx);
+ sha256_update(&sctx, map + i, desc->length);
+ sha256_final(&sctx, sha256);
+ if (memcmp(sha256, desc->sha256, 32) == 0)
+ break;
+ }
+ if ((i + desc->length) > size) {
+ memunmap(map);
+ return -ENOENT;
+ }
+
+ pr_info("Found EFI embedded fw '%s'\n", desc->name);
+
+ fw = kmalloc(sizeof(*fw), GFP_KERNEL);
+ if (!fw) {
+ memunmap(map);
+ return -ENOMEM;
+ }
+
+ fw->data = kmemdup(map + i, desc->length, GFP_KERNEL);
+ memunmap(map);
+ if (!fw->data) {
+ kfree(fw);
+ return -ENOMEM;
+ }
+
+ fw->name = desc->name;
+ fw->length = desc->length;
+ list_add(&fw->list, &efi_embedded_fw_list);
+
+ return 0;
+}
+
+void __init efi_check_for_embedded_firmwares(void)
+{
+ const struct efi_embedded_fw_desc *fw_desc;
+ const struct dmi_system_id *dmi_id;
+ efi_memory_desc_t *md;
+ int i, r;
+
+ for (i = 0; embedded_fw_table[i]; i++) {
+ dmi_id = dmi_first_match(embedded_fw_table[i]);
+ if (!dmi_id)
+ continue;
+
+ fw_desc = dmi_id->driver_data;
+
+ /*
+ * In some drivers the struct driver_data contains may contain
+ * other driver specific data after the fw_desc struct; and
+ * the fw_desc struct itself may be empty, skip these.
+ */
+ if (!fw_desc->name)
+ continue;
+
+ for_each_efi_memory_desc(md) {
+ if (md->type != EFI_BOOT_SERVICES_CODE)
+ continue;
+
+ r = efi_check_md_for_embedded_firmware(md, fw_desc);
+ if (r == 0)
+ break;
+ }
+ }
+
+ checked_for_fw = true;
+}
+
+int efi_get_embedded_fw(const char *name, const u8 **data, size_t *size)
+{
+ struct efi_embedded_fw *iter, *fw = NULL;
+
+ if (!checked_for_fw) {
+ pr_warn("Warning %s called while we did not check for embedded fw\n",
+ __func__);
+ return -ENOENT;
+ }
+
+ list_for_each_entry(iter, &efi_embedded_fw_list, list) {
+ if (strcmp(name, iter->name) == 0) {
+ fw = iter;
+ break;
+ }
+ }
+
+ if (!fw)
+ return -ENOENT;
+
+ *data = fw->data;
+ *size = fw->length;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(efi_get_embedded_fw);
@@ -1554,6 +1554,12 @@ static inline void
efi_enable_reset_attack_mitigation(void) { }
#endif
+#ifdef CONFIG_EFI_EMBEDDED_FIRMWARE
+void efi_check_for_embedded_firmwares(void);
+#else
+static inline void efi_check_for_embedded_firmwares(void) { }
+#endif
+
efi_status_t efi_random_get_seed(void);
void efi_retrieve_tpm2_eventlog(void);
new file mode 100644
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_EFI_EMBEDDED_FW_H
+#define _LINUX_EFI_EMBEDDED_FW_H
+
+#include <linux/list.h>
+#include <linux/mod_devicetable.h>
+
+#define EFI_EMBEDDED_FW_PREFIX_LEN 8
+
+/*
+ * This struct and efi_embedded_fw_list are private to the efi-embedded fw
+ * implementation they are in this header for use by lib/test_firmware.c only!
+ */
+struct efi_embedded_fw {
+ struct list_head list;
+ const char *name;
+ const u8 *data;
+ size_t length;
+};
+
+extern struct list_head efi_embedded_fw_list;
+
+/**
+ * struct efi_embedded_fw_desc - This struct is used by the EFI embedded-fw
+ * code to search for embedded firmwares.
+ *
+ * @name: Name to register the firmware with if found
+ * @prefix: First 8 bytes of the firmware
+ * @length: Length of the firmware in bytes including prefix
+ * @sha256: SHA256 of the firmware
+ */
+struct efi_embedded_fw_desc {
+ const char *name;
+ u8 prefix[EFI_EMBEDDED_FW_PREFIX_LEN];
+ u32 length;
+ u8 sha256[32];
+};
+
+int efi_get_embedded_fw(const char *name, const u8 **dat, size_t *sz);
+
+#endif