--- /dev/null
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2021 Philippe Reynes <philippe.reynes@softathome.com>
+ */
+
+#include <common.h>
+#include <asm/global_data.h>
+DECLARE_GLOBAL_DATA_PTR;
+#include <image.h>
+#include <mapmem.h>
+
+#include <u-boot/sha256.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_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
+
+/*
+ * Information in the device-tree about the signature in the header
+ */
+struct image_sig_info {
+ char *algo_name; /* Name of the algo (eg: sha256,rsa2048) */
+ char *padding_name; /* Name of the padding */
+ u8 *key; /* Public signature key */
+ int key_len; /* Length of the public key */
+ u32 sig_size; /* size of the signature (in the header) */
+ int mandatory; /* Set if the signature is mandatory */
+
+ struct image_sign_info sig_info; /* Signature info */
+};
+
+/*
+ * Header of the signature header
+ */
+struct sig_header_s {
+ u32 magic;
+ u32 version;
+ u32 header_size;
+ u32 image_size;
+ u32 offset_img_sig;
+ u32 flags;
+ u32 reserved0;
+ u32 reserved1;
+ u8 sha256_img_sig[SHA256_SUM_LEN];
+};
+
+#define SIG_HEADER_LEN (sizeof(struct sig_header_s))
+
+/*
+ * Offset of the image
+ *
+ * This value is used to skip the header before really launching the image
+ */
+ulong image_load_offset;
+
+/*
+ * This function gathers information about the signature check
+ * that could be done before launching the image.
+ *
+ * return:
+ * < 0 => 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 *sig_size;
+ int key_len;
+ int node, ret = 0;
+
+ if (!info) {
+ log_err("ERROR: info is NULL for image pre-load sig check\n");
+ ret = -EINVAL;
+ goto out;
+ }
+
+ memset(info, 0, sizeof(*info));
+
+ node = fdt_path_offset(gd_fdt_blob(), IMAGE_PRE_LOAD_PATH);
+ if (node < 0) {
+ log_info("INFO: no info 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 = -EINVAL;
+ goto out;
+ }
+
+ padding_name = fdt_getprop(gd_fdt_blob(), node,
+ IMAGE_PRE_LOAD_PROP_PADDING_NAME, NULL);
+ if (!padding_name) {
+ log_info("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) {
+ log_err("ERROR: no signature-size for image pre-load sig check\n");
+ ret = -EINVAL;
+ goto out;
+ }
+
+ key = fdt_getprop(gd_fdt_blob(), node,
+ IMAGE_PRE_LOAD_PROP_PUBLIC_KEY, &key_len);
+ if (!key) {
+ log_err("ERROR: no key for image pre-load sig check\n");
+ ret = -EINVAL;
+ goto out;
+ }
+
+ 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;
+
+ /* Compute signature information */
+ info->sig_info.name = info->algo_name;
+ info->sig_info.padding = image_get_padding_algo(info->padding_name);
+ info->sig_info.checksum = image_get_checksum_algo(info->sig_info.name);
+ info->sig_info.crypto = image_get_crypto_algo(info->sig_info.name);
+ info->sig_info.key = info->key;
+ info->sig_info.keylen = info->key_len;
+
+ out:
+ return ret;
+}
+
+static int image_pre_load_sig_get_magic(ulong addr, u32 *magic)
+{
+ struct sig_header_s *sig_header;
+ int ret = 0;
+
+ sig_header = (struct sig_header_s *)map_sysmem(addr, SIG_HEADER_LEN);
+ if (!sig_header) {
+ log_err("ERROR: can't map first header\n");
+ ret = -EFAULT;
+ goto out;
+ }
+
+ *magic = fdt32_to_cpu(sig_header->magic);
+
+ unmap_sysmem(sig_header);
+
+ out:
+ return ret;
+}
+
+static int image_pre_load_sig_get_header_size(ulong addr, u32 *header_size)
+{
+ struct sig_header_s *sig_header;
+ int ret = 0;
+
+ sig_header = (struct sig_header_s *)map_sysmem(addr, SIG_HEADER_LEN);
+ if (!sig_header) {
+ log_err("ERROR: can't map first header\n");
+ ret = -EFAULT;
+ goto out;
+ }
+
+ *header_size = fdt32_to_cpu(sig_header->header_size);
+
+ unmap_sysmem(sig_header);
+
+ out:
+ return ret;
+}
+
+/*
+ * return:
+ * < 0 => no magic and magic mandatory (or error when reading magic)
+ * 0 => magic found
+ * 1 => magic NOT found
+ */
+static int image_pre_load_sig_check_magic(struct image_sig_info *info, ulong addr)
+{
+ u32 magic;
+ int ret = 1;
+
+ ret = image_pre_load_sig_get_magic(addr, &magic);
+ if (ret < 0)
+ goto out;
+
+ if (magic != IMAGE_PRE_LOAD_SIG_MAGIC) {
+ if (info->mandatory) {
+ log_err("ERROR: signature is mandatory\n");
+ ret = -EINVAL;
+ goto out;
+ }
+ ret = 1;
+ goto out;
+ }
+
+ ret = 0; /* magic found */
+
+ out:
+ return ret;
+}
+
+static int image_pre_load_sig_check_header_sig(struct image_sig_info *info, ulong addr)
+{
+ void *header;
+ struct image_region reg;
+ u32 sig_len;
+ u8 *sig;
+ int ret = 0;
+
+ /* Only map header of the header and its signature */
+ header = (void *)map_sysmem(addr, SIG_HEADER_LEN + info->sig_size);
+ if (!header) {
+ log_err("ERROR: can't map header\n");
+ ret = -EFAULT;
+ goto out;
+ }
+
+ reg.data = header;
+ reg.size = SIG_HEADER_LEN;
+
+ sig = (uint8_t *)header + SIG_HEADER_LEN;
+ sig_len = info->sig_size;
+
+ ret = info->sig_info.crypto->verify(&info->sig_info, ®, 1, sig, sig_len);
+ if (ret) {
+ log_err("ERROR: header signature check has failed (err=%d)\n", ret);
+ ret = -EINVAL;
+ goto out_unmap;
+ }
+
+ out_unmap:
+ unmap_sysmem(header);
+
+ out:
+ return ret;
+}
+
+static int image_pre_load_sig_check_img_sig_sha256(struct image_sig_info *info, ulong addr)
+{
+ struct sig_header_s *sig_header;
+ u32 header_size, offset_img_sig;
+ void *header;
+ u8 sha256_img_sig[SHA256_SUM_LEN];
+ int ret = 0;
+
+ sig_header = (struct sig_header_s *)map_sysmem(addr, SIG_HEADER_LEN);
+ if (!sig_header) {
+ log_err("ERROR: can't map first header\n");
+ ret = -EFAULT;
+ goto out;
+ }
+
+ header_size = fdt32_to_cpu(sig_header->header_size);
+ offset_img_sig = fdt32_to_cpu(sig_header->offset_img_sig);
+
+ header = (void *)map_sysmem(addr, header_size);
+ if (!header) {
+ log_err("ERROR: can't map header\n");
+ ret = -EFAULT;
+ goto out_sig_header;
+ }
+
+ sha256_csum_wd(header + offset_img_sig, info->sig_size,
+ sha256_img_sig, CHUNKSZ_SHA256);
+
+ ret = memcmp(sig_header->sha256_img_sig, sha256_img_sig, SHA256_SUM_LEN);
+ if (ret) {
+ log_err("ERROR: sha256 of image signature is invalid\n");
+ ret = -EFAULT;
+ goto out_header;
+ }
+
+ out_header:
+ unmap_sysmem(header);
+ out_sig_header:
+ unmap_sysmem(sig_header);
+ out:
+ return ret;
+}
+
+static int image_pre_load_sig_check_img_sig(struct image_sig_info *info, ulong addr)
+{
+ struct sig_header_s *sig_header;
+ u32 header_size, image_size, offset_img_sig;
+ void *image;
+ struct image_region reg;
+ u32 sig_len;
+ u8 *sig;
+ int ret = 0;
+
+ sig_header = (struct sig_header_s *)map_sysmem(addr, SIG_HEADER_LEN);
+ if (!sig_header) {
+ log_err("ERROR: can't map first header\n");
+ ret = -EFAULT;
+ goto out;
+ }
+
+ header_size = fdt32_to_cpu(sig_header->header_size);
+ image_size = fdt32_to_cpu(sig_header->image_size);
+ offset_img_sig = fdt32_to_cpu(sig_header->offset_img_sig);
+
+ unmap_sysmem(sig_header);
+
+ image = (void *)map_sysmem(addr, header_size + image_size);
+ if (!image) {
+ log_err("ERROR: can't map full image\n");
+ ret = -EFAULT;
+ goto out;
+ }
+
+ reg.data = image + header_size;
+ reg.size = image_size;
+
+ sig = (uint8_t *)image + offset_img_sig;
+ sig_len = info->sig_size;
+
+ ret = info->sig_info.crypto->verify(&info->sig_info, ®, 1, sig, sig_len);
+ if (ret) {
+ log_err("ERROR: signature check has failed (err=%d)\n", ret);
+ ret = -EINVAL;
+ goto out_unmap_image;
+ }
+
+ log_info("INFO: signature check has succeed\n");
+
+ out_unmap_image:
+ unmap_sysmem(image);
+
+ out:
+ return ret;
+}
+
+int image_pre_load_sig(ulong addr)
+{
+ struct image_sig_info info;
+ 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_check_magic(&info, addr);
+ if (ret < 0)
+ goto out;
+ if (ret > 0) {
+ ret = 0;
+ goto out;
+ }
+
+ /* Check the signature of the signature header */
+ ret = image_pre_load_sig_check_header_sig(&info, addr);
+ if (ret < 0)
+ goto out;
+
+ /* Check sha256 of the image signature */
+ ret = image_pre_load_sig_check_img_sig_sha256(&info, addr);
+ if (ret < 0)
+ goto out;
+
+ /* Check the image signature */
+ ret = image_pre_load_sig_check_img_sig(&info, addr);
+ if (!ret) {
+ u32 header_size;
+
+ ret = image_pre_load_sig_get_header_size(addr, &header_size);
+ if (ret) {
+ log_err("%s: can't get header size\n", __func__);
+ ret = -EINVAL;
+ goto out;
+ }
+
+ image_load_offset += 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;
+}
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