Merge "Allow --disable-verification when top-level vbmeta is in 'boot'" (8665bb74) · Commits · e / os / android_system_core

fastboot/Android.bp

+5 −1

Original line number	Diff line number	Diff line
		@@ -189,7 +189,11 @@ cc_defaults {
		// will violate ODR.
		shared_libs: [],

		header_libs: ["bootimg_headers"],
		header_libs: [
		"avb_headers",
		"bootimg_headers",
		],

		static_libs: [
		"libziparchive",
		"libsparse",

fastboot/fastboot.cpp

+38 −8

Original line number	Diff line number	Diff line
		@@ -51,6 +51,7 @@
		#include <utility>
		#include <vector>

		#include <android-base/endian.h>
		#include <android-base/file.h>
		#include <android-base/macros.h>
		#include <android-base/parseint.h>
		@@ -59,6 +60,7 @@
		#include <android-base/strings.h>
		#include <android-base/unique_fd.h>
		#include <build/version.h>
		#include <libavb/libavb.h>
		#include <liblp/liblp.h>
		#include <platform_tools_version.h>
		#include <sparse/sparse.h>
		@@ -919,33 +921,50 @@ static bool load_buf(const char* fname, struct fastboot_buffer* buf) {
		return load_buf_fd(fd.release(), buf);
		}

		static void rewrite_vbmeta_buffer(struct fastboot_buffer* buf) {
		static void rewrite_vbmeta_buffer(struct fastboot_buffer* buf, bool vbmeta_in_boot) {
		// Buffer needs to be at least the size of the VBMeta struct which
		// is 256 bytes.
		if (buf->sz < 256) {
		return;
		}

		int fd = make_temporary_fd("vbmeta rewriting");

		std::string data;
		if (!android::base::ReadFdToString(buf->fd, &data)) {
		die("Failed reading from vbmeta");
		}

		uint64_t vbmeta_offset = 0;
		if (vbmeta_in_boot) {
		// Tries to locate top-level vbmeta from boot.img footer.
		uint64_t footer_offset = buf->sz - AVB_FOOTER_SIZE;
		if (0 != data.compare(footer_offset, AVB_FOOTER_MAGIC_LEN, AVB_FOOTER_MAGIC)) {
		die("Failed to find AVB_FOOTER at offset: %" PRId64, footer_offset);
		}
		const AvbFooter* footer = reinterpret_cast<const AvbFooter*>(data.c_str() + footer_offset);
		vbmeta_offset = be64toh(footer->vbmeta_offset);
		}
		// Ensures there is AVB_MAGIC at vbmeta_offset.
		if (0 != data.compare(vbmeta_offset, AVB_MAGIC_LEN, AVB_MAGIC)) {
		die("Failed to find AVB_MAGIC at offset: %" PRId64, vbmeta_offset);
		}

		fprintf(stderr, "Rewriting vbmeta struct at offset: %" PRId64 "\n", vbmeta_offset);

		// There's a 32-bit big endian \|flags\| field at offset 120 where
		// bit 0 corresponds to disable-verity and bit 1 corresponds to
		// disable-verification.
		//
		// See external/avb/libavb/avb_vbmeta_image.h for the layout of
		// the VBMeta struct.
		uint64_t flags_offset = 123 + vbmeta_offset;
		if (g_disable_verity) {
		data[123] \|= 0x01;
		data[flags_offset] \|= 0x01;
		}
		if (g_disable_verification) {
		data[123] \|= 0x02;
		data[flags_offset] \|= 0x02;
		}

		int fd = make_temporary_fd("vbmeta rewriting");
		if (!android::base::WriteStringToFd(data, fd)) {
		die("Failed writing to modified vbmeta");
		}
		@@ -954,14 +973,25 @@ static void rewrite_vbmeta_buffer(struct fastboot_buffer* buf) {
		lseek(fd, 0, SEEK_SET);
		}

		static bool has_vbmeta_partition() {
		std::string partition_type;
		return fb->GetVar("partition-type:vbmeta", &partition_type) == fastboot::SUCCESS \|\|
		fb->GetVar("partition-type:vbmeta_a", &partition_type) == fastboot::SUCCESS \|\|
		fb->GetVar("partition-type:vbmeta_b", &partition_type) == fastboot::SUCCESS;
		}

		static void flash_buf(const std::string& partition, struct fastboot_buffer *buf)
		{
		sparse_file** s;

		// Rewrite vbmeta if that's what we're flashing and modification has been requested.
		if ((g_disable_verity \|\| g_disable_verification) &&
		(partition == "vbmeta" \|\| partition == "vbmeta_a" \|\| partition == "vbmeta_b")) {
		rewrite_vbmeta_buffer(buf);
		if (g_disable_verity \|\| g_disable_verification) {
		if (partition == "vbmeta" \|\| partition == "vbmeta_a" \|\| partition == "vbmeta_b") {
		rewrite_vbmeta_buffer(buf, false /* vbmeta_in_boot */);
		} else if (!has_vbmeta_partition() &&
		(partition == "boot" \|\| partition == "boot_a" \|\| partition == "boot_b")) {
		rewrite_vbmeta_buffer(buf, true /* vbmeta_in_boot */ );
		}
		}

		switch (buf->type) {