kernel: mtdsplit_uimage: add "openwrt, offset" and "openwrt, partition-magic"

Some devices prepend a standard U-Boot Image with a vendor specific
header, having its own magic. Adding two new properties will support
validation of such images, including the additional magic.

Signed-off-by: Bjørn Mork <bjorn@mork.no>

diff --git a/target/linux/generic/files/drivers/mtd/mtdsplit/mtdsplit_uimage.c b/target/linux/generic/files/drivers/mtd/mtdsplit/mtdsplit_uimage.c
index c29eb6234bc2ab412cccb5254d98419cd8c597ad..7a8ccdf8f59afbfa2839bbc5ccf900c57073070c 100644 (file)
--- a/target/linux/generic/files/drivers/mtd/mtdsplit/mtdsplit_uimage.c
+++ b/target/linux/generic/files/drivers/mtd/mtdsplit/mtdsplit_uimage.c
@@ -70,7 +70,8 @@ read_uimage_header(struct mtd_info *mtd, size_t offset, u_char *buf,
 }
 
 static void uimage_parse_dt(struct mtd_info *master, int *extralen,
-                           u32 *ih_magic, u32 *ih_type)
+                           u32 *ih_magic, u32 *ih_type,
+                           u32 *header_offset, u32 *part_magic)
 {
        struct device_node *np = mtd_get_of_node(master);
 
@@ -83,6 +84,10 @@ static void uimage_parse_dt(struct mtd_info *master, int *extralen,
                pr_debug("got openwrt,ih-magic=%08x from device-tree\n", *ih_magic);
        if (!of_property_read_u32(np, "openwrt,ih-type", ih_type))
                pr_debug("got openwrt,ih-type=%08x from device-tree\n", *ih_type);
+       if (!of_property_read_u32(np, "openwrt,offset", header_offset))
+               pr_debug("got ih-start=%u from device-tree\n", *header_offset);
+       if (!of_property_read_u32(np, "openwrt,partition-magic", part_magic))
+               pr_debug("got openwrt,partition-magic=%08x from device-tree\n", *part_magic);
 }
 
 /**
@@ -92,9 +97,9 @@ static void uimage_parse_dt(struct mtd_info *master, int *extralen,
  *      and tail padding length of a valid uImage header if found
  */
 static int __mtdsplit_parse_uimage(struct mtd_info *master,
-                  const struct mtd_partition **pparts,
-                  struct mtd_part_parser_data *data,
-                  ssize_t (*find_header)(u_char *buf, size_t len, u32 ih_magic, u32 ih_type))
+                                  const struct mtd_partition **pparts,
+                                  struct mtd_part_parser_data *data,
+                                  ssize_t (*find_header)(u_char *buf, size_t len, u32 ih_magic, u32 ih_type))
 {
        struct mtd_partition *parts;
        u_char *buf;
@@ -104,11 +109,14 @@ static int __mtdsplit_parse_uimage(struct mtd_info *master,
        size_t uimage_size = 0;
        size_t rootfs_offset;
        size_t rootfs_size = 0;
+       size_t buflen;
        int uimage_part, rf_part;
        int ret;
        int extralen = 0;
        u32 ih_magic = IH_MAGIC;
        u32 ih_type = IH_TYPE_KERNEL;
+       u32 header_offset = 0;
+       u32 part_magic = 0;
        enum mtdsplit_part_type type;
 
        nr_parts = 2;
@@ -116,34 +124,42 @@ static int __mtdsplit_parse_uimage(struct mtd_info *master,
        if (!parts)
                return -ENOMEM;
 
-       buf = vmalloc(MAX_HEADER_LEN);
+       uimage_parse_dt(master, &extralen, &ih_magic, &ih_type, &header_offset, &part_magic);
+       buflen = MAX_HEADER_LEN;
+       buf = vmalloc(buflen);
        if (!buf) {
                ret = -ENOMEM;
                goto err_free_parts;
        }
 
-       uimage_parse_dt(master, &extralen, &ih_magic, &ih_type);
-
        /* find uImage on erase block boundaries */
        for (offset = 0; offset < master->size; offset += master->erasesize) {
                struct uimage_header *header;
 
                uimage_size = 0;
 
-               ret = read_uimage_header(master, offset, buf, MAX_HEADER_LEN);
+               ret = read_uimage_header(master, offset, buf, buflen);
                if (ret)
                        continue;
 
-               ret = find_header(buf, MAX_HEADER_LEN, ih_magic, ih_type);
+               /* verify optional partition magic before uimage header */
+               if (header_offset && part_magic && (be32_to_cpu(*(u32 *)buf) != part_magic))
+                       continue;
+
+               ret = find_header(buf + header_offset, buflen, ih_magic, ih_type);
                if (ret < 0) {
                        pr_debug("no valid uImage found in \"%s\" at offset %llx\n",
                                 master->name, (unsigned long long) offset);
                        continue;
                }
-               header = (struct uimage_header *)(buf + ret);
+
+               /* let uimage_find_edimax override the offset */
+               if (ret > 0)
+                       header_offset = ret;
+               header = (struct uimage_header *)(buf + header_offset);
 
                uimage_size = sizeof(*header) +
-                               be32_to_cpu(header->ih_size) + ret + extralen;
+                               be32_to_cpu(header->ih_size) + header_offset + extralen;
 
                if ((offset + uimage_size) > master->size) {
                        pr_debug("uImage exceeds MTD device \"%s\"\n",
@@ -254,7 +270,7 @@ mtdsplit_uimage_parse_generic(struct mtd_info *master,
                              struct mtd_part_parser_data *data)
 {
        return __mtdsplit_parse_uimage(master, pparts, data,
-                                     uimage_verify_default);
+                                      uimage_verify_default);
 }
 
 static const struct of_device_id mtdsplit_uimage_of_match_table[] = {