From: qianfan Zhao
Not all Android tools use the id field for signing the image with sha1,
so make this feature as optional and disabled default.
Signed-off-by: qianfan Zhao
---
common/Kconfig.boot| 14 +++
common/image-android.c | 55 +-
2 files changed, 63 insertions(+), 6 deletions(-)
diff --git a/common/Kconfig.boot b/common/Kconfig.boot
index a8d4be23a9..11fc8410a9 100644
--- a/common/Kconfig.boot
+++ b/common/Kconfig.boot
@@ -9,6 +9,20 @@ config ANDROID_BOOT_IMAGE
This enables support for booting images which use the Android
image format header.
+if ANDROID_BOOT_IMAGE
+
+config ANDROID_BOOT_IMAGE_VERIFY
+ bool "Enable signature verification"
+ select SHA1
+ default n
+ help
+ This option enables signature verification of Android Boot Images,
+ using a hash signed and verified using SHA1.
+ Not all Android tools use the id field for signing the image with
+ sha1, if you are unsure about this, Say N here.
+
+endif # ANDROID_BOOT_IMAGE
+
config FIT
bool "Support Flattened Image Tree"
select HASH
diff --git a/common/image-android.c b/common/image-android.c
index 1fa1eb..12b84d6fdc 100644
--- a/common/image-android.c
+++ b/common/image-android.c
@@ -44,11 +44,54 @@ static ulong android_image_get_kernel_addr(const struct
andr_img_hdr *hdr)
return hdr->kernel_addr;
}
+#if CONFIG_IS_ENABLED(ANDROID_BOOT_IMAGE_VERIFY)
+/*
+ * Not all Android tools use the id field for signing the image with
+ * sha1 (or anything) so we make this as an optional.
+ */
+static void android_image_update_sha1(sha1_context *ctx, const void *buf,
+ u32 size)
+{
+ if (size > 0) {
+ sha1_update(ctx, buf, size);
+ size = cpu_to_le32(size);
+ sha1_update(ctx, (unsigned char *), sizeof(size));
+ }
+}
+
+static int android_image_verify_sha1(const struct andr_img_hdr *hdr)
+{
+ unsigned char output[20];
+ sha1_context ctx;
+ const void *p;
+
+ sha1_starts();
+
+ p = (void *)hdr + hdr->page_size; /* kernel */
+ android_image_update_sha1(, p, hdr->kernel_size);
+
+ p += ALIGN(hdr->kernel_size, hdr->page_size); /* ramdisk */
+ android_image_update_sha1(, p, hdr->ramdisk_size);
+
+ p += ALIGN(hdr->ramdisk_size, hdr->page_size); /* second */
+ android_image_update_sha1(, p, hdr->second_size);
+
+ sha1_finish(, output);
+
+ return memcmp(output, (unsigned char *)hdr->id, sizeof(output));
+}
+#else
+static int android_image_verify_sha1(const struct andr_img_hdr *hdr)
+{
+ return 0;
+}
+#endif
+
/**
* android_image_get_kernel() - processes kernel part of Android boot images
* @hdr: Pointer to image header, which is at the start
* of the image.
- * @verify:Checksum verification flag. Currently unimplemented.
+ * @verify:Checksum verification flag.
* @os_data: Pointer to a ulong variable, will hold os data start
* address.
* @os_len:Pointer to a ulong variable, will hold os data length.
@@ -66,11 +109,11 @@ int android_image_get_kernel(const struct andr_img_hdr
*hdr, int verify,
const struct image_header *ihdr = (const struct image_header *)
((uintptr_t)hdr + hdr->page_size);
- /*
-* Not all Android tools use the id field for signing the image with
-* sha1 (or anything) so we don't check it. It is not obvious that the
-* string is null terminated so we take care of this.
-*/
+ if (verify && android_image_verify_sha1(hdr) < 0) {
+ puts("Bad Data Hash\n");
+ return -EACCES;
+ }
+
strncpy(andr_tmp_str, hdr->name, ANDR_BOOT_NAME_SIZE);
andr_tmp_str[ANDR_BOOT_NAME_SIZE] = '\0';
if (strlen(andr_tmp_str))
--
2.25.1
