run binwalk without --run-as if needed

ading2210 · Jul 12, 2024 · 3f213fc · 3f213fc
1 parent 91486b0
commit 3f213fc
Showing 1 changed file with 12 additions and 4 deletions.
diff --git a/shim_utils.sh b/shim_utils.sh
@@ -2,6 +2,14 @@
 
 #utilties for reading shim disk images
 
+run_binwalk() {
+  if binwalk -h | grep -- '--run-as' >/dev/null; then
+    binwalk "$@" --run-as=root
+  else
+    binwalk "$@"
+  fi
+}
+
 #extract the initramfs from a kernel image
 extract_initramfs() {
   local kernel_bin="$1"
@@ -10,13 +18,13 @@ extract_initramfs() {
 
   #extract the compressed kernel image from the partition data
   local kernel_file="$(basename $kernel_bin)"
-  local binwalk_out=$(binwalk --extract $kernel_bin --directory=$working_dir --run-as=root)
+  local binwalk_out=$(run_binwalk --extract $kernel_bin --directory=$working_dir)
   local stage1_file=$(echo $binwalk_out | pcregrep -o1 "\d+\s+0x([0-9A-F]+)\s+gzip compressed data")
   local stage1_dir="$working_dir/_$kernel_file.extracted"
   local stage1_path="$stage1_dir/$stage1_file"
 
   #extract the initramfs cpio archive from the kernel image
-  binwalk --extract $stage1_path --directory=$stage1_dir --run-as=root > /dev/null
+  run_binwalk --extract $stage1_path --directory=$stage1_dir > /dev/null
   local stage2_dir="$stage1_dir/_$stage1_file.extracted/"
   local cpio_file=$(file $stage2_dir/* | pcregrep -o1 "([0-9A-F]+):\s+ASCII cpio archive")
   local cpio_path="$stage2_dir/$cpio_file"
@@ -31,7 +39,7 @@ extract_initramfs_arm() {
   local output_dir="$3"
 
   #extract the kernel lz4 archive from the partition
-  local binwalk_out="$(binwalk $kernel_bin --run-as=root)"
+  local binwalk_out="$(run_binwalk $kernel_bin)"
   local lz4_offset="$(echo "$binwalk_out" | pcregrep -o1 "(\d+).+?LZ4 compressed data" | head -n1)"
   local lz4_file="$working_dir/kernel.lz4"
   local kernel_img="$working_dir/kernel_decompressed.bin"
@@ -40,7 +48,7 @@ extract_initramfs_arm() {
 
   #extract the initramfs cpio archive from the kernel image
   local extracted_dir="$working_dir/_kernel_decompressed.bin.extracted"
-  binwalk --extract $kernel_img --directory=$working_dir --run-as=root > /dev/null
+  run_binwalk --extract $kernel_img --directory=$working_dir > /dev/null
   local cpio_file=$(file $extracted_dir/* | pcregrep -o1 "([0-9A-F]+):\s+ASCII cpio archive")
   local cpio_path="$extracted_dir/$cpio_file"