tplink-safeloader: add vendor info support

Some images may contain ASCII vendor info at the start of the image
header. Detect this image type, and display the info when requested.

Signed-off-by: Sander Vanheule <sander@svanheule.net>

diff --git a/src/tplink-safeloader.c b/src/tplink-safeloader.c
index ab08ad1f8580481e440dc2248f9124099a0db194..693745704e875d0d8fa5a9bdfe904aca61890183 100644 (file)
--- a/src/tplink-safeloader.c
+++ b/src/tplink-safeloader.c
@@ -127,8 +127,30 @@ struct __attribute__((__packed__)) soft_version {
        uint32_t compat_level;
 };
 
+/*
+ * Safeloader image type
+ *   Safeloader images contain a 0x14 byte preamble with image size (big endian
+ *   UINT32) and md5 checksum (16 bytes).
+ *
+ * SAFEFLOADER_TYPE_DEFAULT
+ *   Standard preamble with size including preamble length, and checksum.
+ *   Header of 0x1000 bytes, contents of which are not specified.
+ *   Payload starts at offset 0x1014.
+ *
+ * SAFELOADER_TYPE_VENDOR
+ *   Standard preamble with size including preamble length, and checksum.
+ *   Header contains up to 0x1000 bytes of vendor data, starting with a big endian
+ *   UINT32 size, followed by that number of bytes containing (text) data.
+ *   Padded with 0xFF. Payload starts at offset 0x1014.
+ */
+enum safeloader_image_type {
+       SAFELOADER_TYPE_DEFAULT,
+       SAFELOADER_TYPE_VENDOR,
+};
+
 /* Internal representation of safeloader image data */
 struct safeloader_image_info {
+       enum safeloader_image_type type;
        size_t payload_offset;
        struct flash_partition_entry entries[MAX_PARTITIONS];
 };
@@ -3834,6 +3856,11 @@ static void safeloader_parse_image(FILE *input_file, struct safeloader_image_inf
        if (fread(buf, sizeof(buf), 1, input_file) != 1)
                error(1, errno, "Can not read image header");
 
+       if (ntohl(*((uint32_t *) &buf[0])) <= SAFELOADER_HEADER_SIZE)
+               image->type = SAFELOADER_TYPE_VENDOR;
+       else
+               image->type = SAFELOADER_TYPE_DEFAULT;
+
        image->payload_offset = SAFELOADER_PAYLOAD_OFFSET;
 
        /* Parse image partition table */
@@ -3944,6 +3971,21 @@ static int firmware_info(const char *input)
 
        safeloader_parse_image(input_file, &info);
 
+       if (info.type == SAFELOADER_TYPE_VENDOR) {
+               char buf[SAFELOADER_HEADER_SIZE] = {};
+               uint32_t vendor_size;
+
+               fseek(input_file, SAFELOADER_PREAMBLE_SIZE, SEEK_SET);
+               fread(&vendor_size, sizeof(uint32_t), 1, input_file);
+
+               vendor_size = ntohl(vendor_size);
+               fread(buf, vendor_size, 1, input_file);
+
+               printf("Firmware vendor string:\n");
+               fwrite(buf, strnlen(buf, vendor_size), 1, stdout);
+               printf("\n");
+       }
+
        printf("Firmware image partitions:\n");
        printf("%-8s %-8s %s\n", "base", "size", "name");