ar71xx: sysupgrade: improve CPE/WBS 210/510 validation, add new metadata offset

Previously, tplink_pharos_check_image() would accept any image with ELF
magic and only non-printable data in the support-list, as in this case the
while-read loop would not run at all. Add the new support-list offset and
ensure an image is only accepted when the model string is actually found.

Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>

diff --git a/target/linux/ar71xx/base-files/lib/upgrade/platform.sh b/target/linux/ar71xx/base-files/lib/upgrade/platform.sh
index 633a7e8e56731c8ae9f4fecb44cc296e1fcdd8b7..376984a14a122e1f7c567fd5b9c49bb130eabe59 100755 (executable)
--- a/target/linux/ar71xx/base-files/lib/upgrade/platform.sh
+++ b/target/linux/ar71xx/base-files/lib/upgrade/platform.sh
@@ -93,6 +93,22 @@ tplink_get_image_boot_size() {
        get_image "$@" | dd bs=4 count=1 skip=37 2>/dev/null | hexdump -v -n 4 -e '1/1 "%02x"'
 }
 
+tplink_pharos_check_support_list() {
+       local image="$1"
+       local offset="$2"
+       local model="$3"
+
+       # Here $image is given to dd directly instead of using get_image;
+       # otherwise the skip will take almost a second (as dd can't seek)
+       dd if="$image" bs=1 skip=$offset count=1024 2>/dev/null | (
+               while IFS= read -r line; do
+                       [ "$line" = "$model" ] && exit 0
+               done
+
+               exit 1
+       )
+}
+
 tplink_pharos_check_image() {
        local magic_long="$(get_magic_long "$1")"
        [ "$magic_long" != "7f454c46" ] && {
@@ -101,18 +117,10 @@ tplink_pharos_check_image() {
        }
 
        local model_string="$(tplink_pharos_get_model_string)"
-       local line
-
-       # Here $1 is given to dd directly instead of get_image as otherwise the skip
-       # will take almost a second (as dd can't seek then)
-       #
-       # This will fail if the image isn't local, but that's fine: as the
-       # read loop won't be executed at all, it will return true, so the image
-       # is accepted (loading the first 1.5M of a remote image for this check seems
-       # a bit extreme)
-       dd if="$1" bs=1 skip=1511432 count=1024 2>/dev/null | while read line; do
-               [ "$line" = "$model_string" ] && break
-       done || {
+
+       # New images have the support list at 7802888, old ones at 1511432
+       tplink_pharos_check_support_list "$1" 7802888 "$model_string" || \
+       tplink_pharos_check_support_list "$1" 1511432 "$model_string" || {
                echo "Unsupported image (model not in support-list)"
                return 1
        }