[RFC PATCH v2 4/6] common: image: add a stage pre-load
Philippe Reynes
philippe.reynes at softathome.com
Fri Nov 12 10:27:55 CET 2021
This commit adds a stage pre-load that could
check or modify an image.
For the moment, only a header with a signature is
supported. This header has this format:
- magic : 4 bytes
- image size : 4 bytes
- signature : n bytes
- padding : up to header size
The stage use a node /image/pre-load/sig to
get some information:
- header-size (mandatory) : size of the header
- algo-name (mandatory) : name of the algo used to sign
- padding-name : name of padding used to sign
- signature-size : size of the signature (in the header)
- mandatory : set to yes if this sig is mandatory
- public-key (madatory) : value of the public key
Before running the image, the stage pre-load check
the signature provided in the header.
This is an initial support, later we could add the
support of:
- ciphering
- uncompressing
- ...
Signed-off-by: Philippe Reynes <philippe.reynes at softathome.com>
---
common/Kconfig.boot | 33 +++++
common/Makefile | 1 +
common/image-pre-load.c | 291 ++++++++++++++++++++++++++++++++++++++++
include/image.h | 9 ++
4 files changed, 334 insertions(+)
create mode 100644 common/image-pre-load.c
diff --git a/common/Kconfig.boot b/common/Kconfig.boot
index a8d4be23a9..916fdde71f 100644
--- a/common/Kconfig.boot
+++ b/common/Kconfig.boot
@@ -958,6 +958,39 @@ config AUTOBOOT_MENU_SHOW
endmenu
+menu "Image support"
+
+config IMAGE_PRE_LOAD
+ bool "Image pre-load support"
+ help
+ Enable image pre-load support
+
+config SPL_IMAGE_PRE_LOAD
+ bool "Image pre-load support within SPL"
+ depends on SPL && IMAGE_PRE_LOAD
+ help
+ Enable image pre-load support in SPL
+
+config IMAGE_PRE_LOAD_SIG
+ bool "Image pre-load signature support"
+ depends on IMAGE_PRE_LOAD
+ select FIT_SIGNATURE
+ select RSA
+ select RSA_VERIFY_WITH_PKEY
+ help
+ Enable image pre-load signature support
+
+config SPL_IMAGE_PRE_LOAD_SIG
+ bool "Image pre-load signature support witin SPL"
+ depends on SPL_IMAGE_PRE_LOAD && IMAGE_PRE_LOAD_SIG
+ select SPL_FIT_SIGNATURE
+ select SPL_RSA
+ select SPL_RSA_VERIFY_WITH_PKEY
+ help
+ Enable image pre-load signature support in SPL
+
+endmenu
+
config USE_BOOTARGS
bool "Enable boot arguments"
help
diff --git a/common/Makefile b/common/Makefile
index e7839027b6..9b322e3ae4 100644
--- a/common/Makefile
+++ b/common/Makefile
@@ -102,6 +102,7 @@ endif
endif
obj-y += image.o image-board.o
+obj-$(CONFIG_$(SPL_TPL_)IMAGE_PRE_LOAD) += image-pre-load.o
obj-$(CONFIG_$(SPL_TPL_)HASH) += hash.o
obj-$(CONFIG_ANDROID_AB) += android_ab.o
obj-$(CONFIG_ANDROID_BOOT_IMAGE) += image-android.o image-android-dt.o
diff --git a/common/image-pre-load.c b/common/image-pre-load.c
new file mode 100644
index 0000000000..6ed21c3f51
--- /dev/null
+++ b/common/image-pre-load.c
@@ -0,0 +1,291 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2021 Philippe Reynes <philippe.reynes at softathome.com>
+ */
+
+#include <common.h>
+#include <asm/global_data.h>
+DECLARE_GLOBAL_DATA_PTR;
+#include <image.h>
+#include <mapmem.h>
+
+#define IMAGE_PRE_LOAD_SIG_MAGIC 0x55425348
+#define IMAGE_PRE_LOAD_SIG_OFFSET_MAGIC 0
+#define IMAGE_PRE_LOAD_SIG_OFFSET_IMG_LEN 4
+#define IMAGE_PRE_LOAD_SIG_OFFSET_SIG 8
+
+#define IMAGE_PRE_LOAD_PATH "/image/pre-load/sig"
+#define IMAGE_PRE_LOAD_PROP_HEADER_SIZE "header-size"
+#define IMAGE_PRE_LOAD_PROP_ALGO_NAME "algo-name"
+#define IMAGE_PRE_LOAD_PROP_PADDING_NAME "padding-name"
+#define IMAGE_PRE_LOAD_PROP_SIG_SIZE "signature-size"
+#define IMAGE_PRE_LOAD_PROP_PUBLIC_KEY "public-key"
+#define IMAGE_PRE_LOAD_PROP_MANDATORY "mandatory"
+
+#ifndef CONFIG_SYS_BOOTM_LEN
+/* use 8MByte as default max gunzip size */
+#define CONFIG_SYS_BOOTM_LEN 0x800000
+#endif
+
+struct image_sig_header {
+ u32 magic;
+ u32 size;
+ u8 *sig;
+};
+
+struct image_sig_info {
+ ulong header_size;
+ char *algo_name;
+ char *padding_name;
+ u8 *key;
+ int key_len;
+ u32 sig_size;
+ int mandatory;
+};
+
+ulong image_load_offset;
+
+/*
+ * This function gathers information about the signature check
+ * that could be done before launching the image.
+ *
+ * return:
+ * -1 => an error has occurred
+ * 0 => OK
+ * 1 => no setup
+ */
+static int image_pre_load_sig_setup(struct image_sig_info *info)
+{
+ const void *algo_name, *padding_name, *key, *mandatory;
+ const u32 *header_size, *sig_size;
+ int key_len;
+ int node, ret = 0;
+
+ if (!info) {
+ printf("ERROR: info is NULL for image pre-load sig check\n");
+ ret = -1;
+ goto out;
+ }
+
+ memset(info, 0, sizeof(*info));
+
+ node = fdt_path_offset(gd_fdt_blob(), IMAGE_PRE_LOAD_PATH);
+ if (node < 0) {
+ printf("INFO: no info for image pre-load sig check\n");
+ ret = 1;
+ goto out;
+ }
+
+ header_size = fdt_getprop(gd_fdt_blob(), node,
+ IMAGE_PRE_LOAD_PROP_HEADER_SIZE, NULL);
+ if (!header_size) {
+ printf("ERROR: no header-size for image pre-load sig check\n");
+ ret = -1;
+ goto out;
+ }
+
+ algo_name = fdt_getprop(gd_fdt_blob(), node,
+ IMAGE_PRE_LOAD_PROP_ALGO_NAME, NULL);
+ if (!algo_name) {
+ printf("ERROR: no algo_name for image pre-load sig check\n");
+ ret = -1;
+ goto out;
+ }
+
+ padding_name = fdt_getprop(gd_fdt_blob(), node,
+ IMAGE_PRE_LOAD_PROP_PADDING_NAME, NULL);
+ if (!padding_name) {
+ printf("INFO: no padding_name provided, so using pkcs-1.5\n");
+ padding_name = "pkcs-1.5";
+ }
+
+ sig_size = fdt_getprop(gd_fdt_blob(), node,
+ IMAGE_PRE_LOAD_PROP_SIG_SIZE, NULL);
+ if (!sig_size) {
+ printf("ERROR: no signature-size for image pre-load sig check\n");
+ ret = -1;
+ goto out;
+ }
+
+ key = fdt_getprop(gd_fdt_blob(), node,
+ IMAGE_PRE_LOAD_PROP_PUBLIC_KEY, &key_len);
+ if (!key) {
+ printf("ERROR: no key for image pre-load sig check\n");
+ ret = -1;
+ goto out;
+ }
+
+ info->header_size = fdt32_to_cpu(*header_size);
+ info->algo_name = (char *)algo_name;
+ info->padding_name = (char *)padding_name;
+ info->key = (uint8_t *)key;
+ info->key_len = key_len;
+ info->sig_size = fdt32_to_cpu(*sig_size);
+
+ mandatory = fdt_getprop(gd_fdt_blob(), node,
+ IMAGE_PRE_LOAD_PROP_MANDATORY, NULL);
+ if (mandatory && !strcmp((char *)mandatory, "yes"))
+ info->mandatory = 1;
+
+ out:
+ return ret;
+}
+
+static int image_pre_load_sig_get_header_u32(struct image_sig_info *info,
+ ulong addr, u32 offset,
+ u32 *value)
+{
+ void *header;
+ u32 *tmp;
+ int ret = 0;
+
+ header = map_sysmem(addr, info->header_size);
+ if (!header) {
+ printf("ERROR: can't map header image pre-load sig\n");
+ ret = -1;
+ goto out;
+ }
+
+ tmp = header + offset;
+ *value = be32_to_cpu(*tmp);
+
+ unmap_sysmem(header);
+
+ out:
+ return ret;
+}
+
+static int image_pre_load_sig_get_magic(struct image_sig_info *info,
+ ulong addr, u32 *magic)
+{
+ int ret;
+
+ ret = image_pre_load_sig_get_header_u32(info, addr,
+ IMAGE_PRE_LOAD_SIG_OFFSET_MAGIC, magic);
+
+ return ret;
+}
+
+static int image_pre_load_sig_get_img_len(struct image_sig_info *info,
+ ulong addr, u32 *len)
+{
+ int ret;
+
+ ret = image_pre_load_sig_get_header_u32(info, addr,
+ IMAGE_PRE_LOAD_SIG_OFFSET_IMG_LEN, len);
+ if (ret < 0)
+ goto out;
+
+ if (*len > CONFIG_SYS_BOOTM_LEN) {
+ printf("ERROR: size of image (%u) bigger than CONFIG_SYS_BOOTM_LEN (%u)\n",
+ *len, CONFIG_SYS_BOOTM_LEN);
+ ret = -1;
+ goto out;
+ }
+
+ if (*len == 0) {
+ printf("ERROR: size of image (%u) is zero\n", *len);
+ ret = -1;
+ goto out;
+ }
+
+ out:
+ return ret;
+}
+
+static int image_pre_load_sig_check(struct image_sig_info *info, ulong addr, int img_len)
+{
+ void *image;
+ struct image_sign_info sig_info;
+ struct image_region reg;
+ u32 sig_len;
+ u8 *sig;
+ int ret = 0;
+
+ image = (void *)map_sysmem(addr, info->header_size + img_len);
+ if (!image) {
+ printf("ERROR: can't map full image\n");
+ ret = -1;
+ goto out;
+ }
+
+ memset(&sig_info, 0, sizeof(sig_info));
+ sig_info.name = info->algo_name;
+ sig_info.padding = image_get_padding_algo(info->padding_name);
+ sig_info.checksum = image_get_checksum_algo(sig_info.name);
+ sig_info.crypto = image_get_crypto_algo(sig_info.name);
+ sig_info.key = info->key;
+ sig_info.keylen = info->key_len;
+
+ reg.data = image + info->header_size;
+ reg.size = img_len;
+
+ sig = (uint8_t *)image + IMAGE_PRE_LOAD_SIG_OFFSET_SIG;
+ sig_len = info->sig_size;
+
+ ret = sig_info.crypto->verify(&sig_info, ®, 1, sig, sig_len);
+ if (ret) {
+ printf("ERROR: signature check has failed (err=%d)\n", ret);
+ ret = -1;
+ goto out_unmap;
+ }
+
+ printf("INFO: signature check has succeed\n");
+
+out_unmap:
+ unmap_sysmem(image);
+
+ out:
+ return ret;
+}
+
+int image_pre_load_sig(ulong addr)
+{
+ struct image_sig_info info;
+ u32 magic, img_len;
+ int ret;
+
+ ret = image_pre_load_sig_setup(&info);
+ if (ret < 0)
+ goto out;
+ if (ret > 0) {
+ ret = 0;
+ goto out;
+ }
+
+ ret = image_pre_load_sig_get_magic(&info, addr, &magic);
+ if (ret < 0)
+ goto out;
+
+ if (magic != IMAGE_PRE_LOAD_SIG_MAGIC) {
+ if (info.mandatory) {
+ printf("ERROR: signature is mandatory\n");
+ ret = -1;
+ }
+ goto out;
+ }
+
+ ret = image_pre_load_sig_get_img_len(&info, addr, &img_len);
+ if (ret < 0)
+ goto out;
+
+ ret = image_pre_load_sig_check(&info, addr, img_len);
+
+ if (!ret)
+ image_load_offset += info.header_size;
+
+ out:
+ return ret;
+}
+
+int image_pre_load(ulong addr)
+{
+ int ret = 0;
+
+ image_load_offset = 0;
+
+ if (CONFIG_IS_ENABLED(IMAGE_PRE_LOAD_SIG))
+ ret = image_pre_load_sig(addr);
+
+ return ret;
+}
diff --git a/include/image.h b/include/image.h
index fd662e74b4..5f83e4c747 100644
--- a/include/image.h
+++ b/include/image.h
@@ -48,6 +48,7 @@ struct fdt_region;
extern ulong image_load_addr; /* Default Load Address */
extern ulong image_save_addr; /* Default Save Address */
extern ulong image_save_size; /* Default Save Size */
+extern ulong image_load_offset; /* Default Load Address Offset */
/* An invalid size, meaning that the image size is not known */
#define IMAGE_SIZE_INVAL (-1UL)
@@ -1289,6 +1290,14 @@ struct crypto_algo *image_get_crypto_algo(const char *full_name);
*/
struct padding_algo *image_get_padding_algo(const char *name);
+/**
+ * image_pre_load() - Manage pre load header
+ *
+ * @param addr Address of the image
+ * @return: 0 on success, -ve on error
+ */
+int image_pre_load(ulong addr);
+
/**
* fit_image_verify_required_sigs() - Verify signatures marked as 'required'
*
--
2.17.1
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