/*
* Copyright (C) 2008 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "applypatch/applypatch.h"
#include <errno.h>
#include <fcntl.h>
#include <libgen.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/statfs.h>
#include <sys/types.h>
#include <unistd.h>
#include <functional>
#include <memory>
#include <string>
#include <utility>
#include <vector>
#include <android-base/logging.h>
#include <android-base/parseint.h>
#include <android-base/strings.h>
#include <openssl/sha.h>
#include "edify/expr.h"
#include "otafault/ota_io.h"
#include "otautil/cache_location.h"
#include "otautil/print_sha1.h"
static int LoadPartitionContents(const std::string& filename, FileContents* file);
static size_t FileSink(const unsigned char* data, size_t len, int fd);
static int GenerateTarget(const FileContents& source_file, const std::unique_ptr<Value>& patch,
const std::string& target_filename,
const uint8_t target_sha1[SHA_DIGEST_LENGTH], const Value* bonus_data);
// Read a file into memory; store the file contents and associated metadata in *file.
// Return 0 on success.
int LoadFileContents(const char* filename, FileContents* file) {
// A special 'filename' beginning with "EMMC:" means to load the contents of a partition.
if (strncmp(filename, "EMMC:", 5) == 0) {
return LoadPartitionContents(filename, file);
}
struct stat sb;
if (stat(filename, &sb) == -1) {
printf("failed to stat \"%s\": %s\n", filename, strerror(errno));
return -1;
}
std::vector<unsigned char> data(sb.st_size);
unique_file f(ota_fopen(filename, "rb"));
if (!f) {
printf("failed to open \"%s\": %s\n", filename, strerror(errno));
return -1;
}
size_t bytes_read = ota_fread(data.data(), 1, data.size(), f.get());
if (bytes_read != data.size()) {
printf("short read of \"%s\" (%zu bytes of %zu)\n", filename, bytes_read, data.size());
return -1;
}
file->data = std::move(data);
SHA1(file->data.data(), file->data.size(), file->sha1);
return 0;
}
// Load the contents of an EMMC partition into the provided
// FileContents. filename should be a string of the form
// "EMMC:<partition_device>:...". The smallest size_n bytes for
// which that prefix of the partition contents has the corresponding
// sha1 hash will be loaded. It is acceptable for a size value to be
// repeated with different sha1s. Will return 0 on success.
//
// This complexity is needed because if an OTA installation is
// interrupted, the partition might contain either the source or the
// target data, which might be of different lengths. We need to know
// the length in order to read from a partition (there is no
// "end-of-file" marker), so the caller must specify the possible
// lengths and the hash of the data, and we'll do the load expecting
// to find one of those hashes.
static int LoadPartitionContents(const std::string& filename, FileContents* file) {
std::vector<std::string> pieces = android::base::Split(filename, ":");
if (pieces.size() < 4 || pieces.size() % 2 != 0 || pieces[0] != "EMMC") {
printf("LoadPartitionContents called with bad filename \"%s\"\n", filename.c_str());
return -1;
}
size_t pair_count = (pieces.size() - 2) / 2; // # of (size, sha1) pairs in filename
std::vector<std::pair<size_t, std::string>> pairs;
for (size_t i = 0; i < pair_count; ++i) {
size_t size;
if (!android::base::ParseUint(pieces[i * 2 + 2], &size) || size == 0) {
printf("LoadPartitionContents called with bad size \"%s\"\n", pieces[i * 2 + 2].c_str());
return -1;
}
pairs.push_back({ size, pieces[i * 2 + 3] });
}
// Sort the pairs array so that they are in order of increasing size.
std::sort(pairs.begin(), pairs.end());
const char* partition = pieces[1].c_str();
unique_file dev(ota_fopen(partition, "rb"));
if (!dev) {
printf("failed to open emmc partition \"%s\": %s\n", partition, strerror(errno));
return -1;
}
SHA_CTX sha_ctx;
SHA1_Init(&sha_ctx);
// Allocate enough memory to hold the largest size.
std::vector<unsigned char> buffer(pairs[pair_count - 1].first);
unsigned char* buffer_ptr = buffer.data();
size_t buffer_size = 0; // # bytes read so far
bool found = false;
for (const auto& pair : pairs) {
size_t current_size = pair.first;
const std::string& current_sha1 = pair.second;
// Read enough additional bytes to get us up to the next size. (Again,
// we're trying the possibilities in order of increasing size).
size_t next = current_size - buffer_size;
if (next > 0) {
size_t read = ota_fread(buffer_ptr, 1, next, dev.get());
if (next != read) {
printf("short read (%zu bytes of %zu) for partition \"%s\"\n", read, next, partition);
return -1;
}
SHA1_Update(&sha_ctx, buffer_ptr, read);
buffer_size += read;
buffer_ptr += read;
}
// Duplicate the SHA context and finalize the duplicate so we can
// check it against this pair's expected hash.
SHA_CTX temp_ctx;
memcpy(&temp_ctx, &sha_ctx, sizeof(SHA_CTX));
uint8_t sha_so_far[SHA_DIGEST_LENGTH];
SHA1_Final(sha_so_far, &temp_ctx);
uint8_t parsed_sha[SHA_DIGEST_LENGTH];
if (ParseSha1(current_sha1.c_str(), parsed_sha) != 0) {
printf("failed to parse SHA-1 %s in %s\n", current_sha1.c_str(), filename.c_str());
return -1;
}
if (memcmp(sha_so_far, parsed_sha, SHA_DIGEST_LENGTH) == 0) {
// We have a match. Stop reading the partition; we'll return the data we've read so far.
printf("partition read matched size %zu SHA-1 %s\n", current_size, current_sha1.c_str());
found = true;
break;
}
}
if (!found) {
// Ran off the end of the list of (size, sha1) pairs without finding a match.
printf("contents of partition \"%s\" didn't match %s\n", partition, filename.c_str());
return -1;
}
SHA1_Final(file->sha1, &sha_ctx);
buffer.resize(buffer_size);
file->data = std::move(buffer);
return 0;
}
// Save the contents of the given FileContents object under the given
// filename. Return 0 on success.
int SaveFileContents(const char* filename, const FileContents* file) {
unique_fd fd(ota_open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_SYNC, S_IRUSR | S_IWUSR));
if (fd == -1) {
printf("failed to open \"%s\" for write: %s\n", filename, strerror(errno));
return -1;
}
size_t bytes_written = FileSink(file->data.data(), file->data.size(), fd);
if (bytes_written != file->data.size()) {
printf("short write of \"%s\" (%zd bytes of %zu): %s\n", filename, bytes_written,
file->data.size(), strerror(errno));
return -1;
}
if (ota_fsync(fd) != 0) {
printf("fsync of \"%s\" failed: %s\n", filename, strerror(errno));
return -1;
}
if (ota_close(fd) != 0) {
printf("close of \"%s\" failed: %s\n", filename, strerror(errno));
return -1;
}
return 0;
}
// Write a memory buffer to 'target' partition, a string of the form
// "EMMC:<partition_device>[:...]". The target name
// might contain multiple colons, but WriteToPartition() only uses the first
// two and ignores the rest. Return 0 on success.
int WriteToPartition(const unsigned char* data, size_t len, const std::string& target) {
std::vector<std::string> pieces = android::base::Split(target, ":");
if (pieces.size() < 2 || pieces[0] != "EMMC") {
printf("WriteToPartition called with bad target (%s)\n", target.c_str());
return -1;
}
const char* partition = pieces[1].c_str();
unique_fd fd(ota_open(partition, O_RDWR));
if (fd == -1) {
printf("failed to open %s: %s\n", partition, strerror(errno));
return -1;
}
size_t start = 0;
bool success = false;
for (size_t attempt = 0; attempt < 2; ++attempt) {
if (TEMP_FAILURE_RETRY(lseek(fd, start, SEEK_SET)) == -1) {
printf("failed seek on %s: %s\n", partition, strerror(errno));
return -1;
}
while (start < len) {
size_t to_write = len - start;
if (to_write > 1 << 20) to_write = 1 << 20;
ssize_t written = TEMP_FAILURE_RETRY(ota_write(fd, data + start, to_write));
if (written == -1) {
printf("failed write writing to %s: %s\n", partition, strerror(errno));
return -1;
}
start += written;
}
if (ota_fsync(fd) != 0) {
printf("failed to sync to %s: %s\n", partition, strerror(errno));
return -1;
}
if (ota_close(fd) != 0) {
printf("failed to close %s: %s\n", partition, strerror(errno));
return -1;
}
fd.reset(ota_open(partition, O_RDONLY));
if (fd == -1) {
printf("failed to reopen %s for verify: %s\n", partition, strerror(errno));
return -1;
}
// Drop caches so our subsequent verification read won't just be reading the cache.
sync();
unique_fd dc(ota_open("/proc/sys/vm/drop_caches", O_WRONLY));
if (TEMP_FAILURE_RETRY(ota_write(dc, "3\n", 2)) == -1) {
printf("write to /proc/sys/vm/drop_caches failed: %s\n", strerror(errno));
} else {
printf(" caches dropped\n");
}
ota_close(dc);
sleep(1);
// Verify.
if (TEMP_FAILURE_RETRY(lseek(fd, 0, SEEK_SET)) == -1) {
printf("failed to seek back to beginning of %s: %s\n", partition, strerror(errno));
return -1;
}
unsigned char buffer[4096];
start = len;
for (size_t p = 0; p < len; p += sizeof(buffer)) {
size_t to_read = len - p;
if (to_read > sizeof(buffer)) {
to_read = sizeof(buffer);
}
size_t so_far = 0;
while (so_far < to_read) {
ssize_t read_count = TEMP_FAILURE_RETRY(ota_read(fd, buffer + so_far, to_read - so_far));
if (read_count == -1) {
printf("verify read error %s at %zu: %s\n", partition, p, strerror(errno));
return -1;
} else if (read_count == 0) {
printf("verify read reached unexpected EOF, %s at %zu\n", partition, p);
return -1;
}
if (static_cast<size_t>(read_count) < to_read) {
printf("short verify read %s at %zu: %zd %zu\n", partition, p, read_count, to_read);
}
so_far += read_count;
}
if (memcmp(buffer, data + p, to_read) != 0) {
printf("verification failed starting at %zu\n", p);
start = p;
break;
}
}
if (start == len) {
printf("verification read succeeded (attempt %zu)\n", attempt + 1);
success = true;
break;
}
if (ota_close(fd) != 0) {
printf("failed to close %s: %s\n", partition, strerror(errno));
return -1;
}
fd.reset(ota_open(partition, O_RDWR));
if (fd == -1) {
printf("failed to reopen %s for retry write && verify: %s\n", partition, strerror(errno));
return -1;
}
}
if (!success) {
printf("failed to verify after all attempts\n");
return -1;
}
if (ota_close(fd) == -1) {
printf("error closing %s: %s\n", partition, strerror(errno));
return -1;
}
sync();
return 0;
}
// Take a string 'str' of 40 hex digits and parse it into the 20
// byte array 'digest'. 'str' may contain only the digest or be of
// the form "<digest>:<anything>". Return 0 on success, -1 on any
// error.
int ParseSha1(const char* str, uint8_t* digest) {
const char* ps = str;
uint8_t* pd = digest;
for (int i = 0; i < SHA_DIGEST_LENGTH * 2; ++i, ++ps) {
int digit;
if (*ps >= '0' && *ps <= '9') {
digit = *ps - '0';
} else if (*ps >= 'a' && *ps <= 'f') {
digit = *ps - 'a' + 10;
} else if (*ps >= 'A' && *ps <= 'F') {
digit = *ps - 'A' + 10;
} else {
return -1;
}
if (i % 2 == 0) {
*pd = digit << 4;
} else {
*pd |= digit;
++pd;
}
}
if (*ps != '\0') return -1;
return 0;
}
// Search an array of sha1 strings for one matching the given sha1.
// Return the index of the match on success, or -1 if no match is
// found.
static int FindMatchingPatch(uint8_t* sha1, const std::vector<std::string>& patch_sha1_str) {
for (size_t i = 0; i < patch_sha1_str.size(); ++i) {
uint8_t patch_sha1[SHA_DIGEST_LENGTH];
if (ParseSha1(patch_sha1_str[i].c_str(), patch_sha1) == 0 &&
memcmp(patch_sha1, sha1, SHA_DIGEST_LENGTH) == 0) {
return i;
}
}
return -1;
}
// Returns 0 if the contents of the file (argv[2]) or the cached file
// match any of the sha1's on the command line (argv[3:]). Returns
// nonzero otherwise.
int applypatch_check(const char* filename, const std::vector<std::string>& patch_sha1_str) {
FileContents file;
// It's okay to specify no sha1s; the check will pass if the
// LoadFileContents is successful. (Useful for reading
// partitions, where the filename encodes the sha1s; no need to
// check them twice.)
if (LoadFileContents(filename, &file) != 0 ||
(!patch_sha1_str.empty() && FindMatchingPatch(file.sha1, patch_sha1_str) < 0)) {
printf("file \"%s\" doesn't have any of expected sha1 sums; checking cache\n", filename);
// If the source file is missing or corrupted, it might be because we were killed in the middle
// of patching it. A copy of it should have been made in cache_temp_source. If that file
// exists and matches the sha1 we're looking for, the check still passes.
if (LoadFileContents(CacheLocation::location().cache_temp_source().c_str(), &file) != 0) {
printf("failed to load cache file\n");
return 1;
}
if (FindMatchingPatch(file.sha1, patch_sha1_str) < 0) {
printf("cache bits don't match any sha1 for \"%s\"\n", filename);
return 1;
}
}
return 0;
}
int ShowLicenses() {
ShowBSDiffLicense();
return 0;
}
static size_t FileSink(const unsigned char* data, size_t len, int fd) {
size_t done = 0;
while (done < len) {
ssize_t wrote = TEMP_FAILURE_RETRY(ota_write(fd, data + done, len - done));
if (wrote == -1) {
printf("error writing %zd bytes: %s\n", (len - done), strerror(errno));
return done;
}
done += wrote;
}
return done;
}
// Return the amount of free space (in bytes) on the filesystem
// containing filename. filename must exist. Return -1 on error.
size_t FreeSpaceForFile(const char* filename) {
struct statfs sf;
if (statfs(filename, &sf) != 0) {
printf("failed to statfs %s: %s\n", filename, strerror(errno));
return -1;
}
return sf.f_bsize * sf.f_bavail;
}
int CacheSizeCheck(size_t bytes) {
if (MakeFreeSpaceOnCache(bytes) < 0) {
printf("unable to make %zu bytes available on /cache\n", bytes);
return 1;
}
return 0;
}
// This function applies binary patches to EMMC target files in a way that is safe (the original
// file is not touched until we have the desired replacement for it) and idempotent (it's okay to
// run this program multiple times).
//
// - If the SHA-1 hash of <target_filename> is <target_sha1_string>, does nothing and exits
// successfully.
//
// - Otherwise, if the SHA-1 hash of <source_filename> is one of the entries in <patch_sha1_str>,
// the corresponding patch from <patch_data> (which must be a VAL_BLOB) is applied to produce a
// new file (the type of patch is automatically detected from the blob data). If that new file
// has SHA-1 hash <target_sha1_str>, moves it to replace <target_filename>, and exits
// successfully. Note that if <source_filename> and <target_filename> are not the same,
// <source_filename> is NOT deleted on success. <target_filename> may be the string "-" to mean
// "the same as <source_filename>".
//
// - Otherwise, or if any error is encountered, exits with non-zero status.
//
// <source_filename> must refer to an EMMC partition to read the source data. See the comments for
// the LoadPartitionContents() function above for the format of such a filename. <target_size> has
// become obsolete since we have dropped the support for patching non-EMMC targets (EMMC targets
// have the size embedded in the filename).
int applypatch(const char* source_filename, const char* target_filename,
const char* target_sha1_str, size_t /* target_size */,
const std::vector<std::string>& patch_sha1_str,
const std::vector<std::unique_ptr<Value>>& patch_data, const Value* bonus_data) {
printf("patch %s: ", source_filename);
if (target_filename[0] == '-' && target_filename[1] == '\0') {
target_filename = source_filename;
}
if (strncmp(target_filename, "EMMC:", 5) != 0) {
printf("Supporting patching EMMC targets only.\n");
return 1;
}
uint8_t target_sha1[SHA_DIGEST_LENGTH];
if (ParseSha1(target_sha1_str, target_sha1) != 0) {
printf("failed to parse tgt-sha1 \"%s\"\n", target_sha1_str);
return 1;
}
// We try to load the target file into the source_file object.
FileContents source_file;
if (LoadFileContents(target_filename, &source_file) == 0) {
if (memcmp(source_file.sha1, target_sha1, SHA_DIGEST_LENGTH) == 0) {
// The early-exit case: the patch was already applied, this file has the desired hash, nothing
// for us to do.
printf("already %s\n", short_sha1(target_sha1).c_str());
return 0;
}
}
if (source_file.data.empty() ||
(target_filename != source_filename && strcmp(target_filename, source_filename) != 0)) {
// Need to load the source file: either we failed to load the target file, or we did but it's
// different from the expected.
source_file.data.clear();
LoadFileContents(source_filename, &source_file);
}
if (!source_file.data.empty()) {
int to_use = FindMatchingPatch(source_file.sha1, patch_sha1_str);
if (to_use != -1) {
return GenerateTarget(source_file, patch_data[to_use], target_filename, target_sha1,
bonus_data);
}
}
printf("source file is bad; trying copy\n");
FileContents copy_file;
if (LoadFileContents(CacheLocation::location().cache_temp_source().c_str(), ©_file) < 0) {
printf("failed to read copy file\n");
return 1;
}
int to_use = FindMatchingPatch(copy_file.sha1, patch_sha1_str);
if (to_use == -1) {
printf("copy file doesn't match source SHA-1s either\n");
return 1;
}
return GenerateTarget(copy_file, patch_data[to_use], target_filename, target_sha1, bonus_data);
}
/*
* This function flashes a given image to the target partition. It verifies
* the target cheksum first, and will return if target has the desired hash.
* It checks the checksum of the given source image before flashing, and
* verifies the target partition afterwards. The function is idempotent.
* Returns zero on success.
*/
int applypatch_flash(const char* source_filename, const char* target_filename,
const char* target_sha1_str, size_t target_size) {
printf("flash %s: ", target_filename);
uint8_t target_sha1[SHA_DIGEST_LENGTH];
if (ParseSha1(target_sha1_str, target_sha1) != 0) {
printf("failed to parse tgt-sha1 \"%s\"\n", target_sha1_str);
return 1;
}
std::string target_str(target_filename);
std::vector<std::string> pieces = android::base::Split(target_str, ":");
if (pieces.size() != 2 || pieces[0] != "EMMC") {
printf("invalid target name \"%s\"", target_filename);
return 1;
}
// Load the target into the source_file object to see if already applied.
pieces.push_back(std::to_string(target_size));
pieces.push_back(target_sha1_str);
std::string fullname = android::base::Join(pieces, ':');
FileContents source_file;
if (LoadPartitionContents(fullname, &source_file) == 0 &&
memcmp(source_file.sha1, target_sha1, SHA_DIGEST_LENGTH) == 0) {
// The early-exit case: the image was already applied, this partition
// has the desired hash, nothing for us to do.
printf("already %s\n", short_sha1(target_sha1).c_str());
return 0;
}
if (LoadFileContents(source_filename, &source_file) == 0) {
if (memcmp(source_file.sha1, target_sha1, SHA_DIGEST_LENGTH) != 0) {
// The source doesn't have desired checksum.
printf("source \"%s\" doesn't have expected sha1 sum\n", source_filename);
printf("expected: %s, found: %s\n", short_sha1(target_sha1).c_str(),
short_sha1(source_file.sha1).c_str());
return 1;
}
}
if (WriteToPartition(source_file.data.data(), target_size, target_filename) != 0) {
printf("write of copied data to %s failed\n", target_filename);
return 1;
}
return 0;
}
static int GenerateTarget(const FileContents& source_file, const std::unique_ptr<Value>& patch,
const std::string& target_filename,
const uint8_t target_sha1[SHA_DIGEST_LENGTH], const Value* bonus_data) {
if (patch->type != VAL_BLOB) {
printf("patch is not a blob\n");
return 1;
}
const char* header = &patch->data[0];
size_t header_bytes_read = patch->data.size();
bool use_bsdiff = false;
if (header_bytes_read >= 8 && memcmp(header, "BSDIFF40", 8) == 0) {
use_bsdiff = true;
} else if (header_bytes_read >= 8 && memcmp(header, "IMGDIFF2", 8) == 0) {
use_bsdiff = false;
} else {
printf("Unknown patch file format\n");
return 1;
}
CHECK(android::base::StartsWith(target_filename, "EMMC:"));
// We still write the original source to cache, in case the partition write is interrupted.
if (MakeFreeSpaceOnCache(source_file.data.size()) < 0) {
printf("not enough free space on /cache\n");
return 1;
}
if (SaveFileContents(CacheLocation::location().cache_temp_source().c_str(), &source_file) < 0) {
printf("failed to back up source file\n");
return 1;
}
// We store the decoded output in memory.
std::string memory_sink_str; // Don't need to reserve space.
SinkFn sink = [&memory_sink_str](const unsigned char* data, size_t len) {
memory_sink_str.append(reinterpret_cast<const char*>(data), len);
return len;
};
SHA_CTX ctx;
SHA1_Init(&ctx);
int result;
if (use_bsdiff) {
result =
ApplyBSDiffPatch(source_file.data.data(), source_file.data.size(), *patch, 0, sink, &ctx);
} else {
result = ApplyImagePatch(source_file.data.data(), source_file.data.size(), *patch, sink, &ctx,
bonus_data);
}
if (result != 0) {
printf("applying patch failed\n");
return 1;
}
uint8_t current_target_sha1[SHA_DIGEST_LENGTH];
SHA1_Final(current_target_sha1, &ctx);
if (memcmp(current_target_sha1, target_sha1, SHA_DIGEST_LENGTH) != 0) {
printf("patch did not produce expected sha1\n");
return 1;
} else {
printf("now %s\n", short_sha1(target_sha1).c_str());
}
// Write back the temp file to the partition.
if (WriteToPartition(reinterpret_cast<const unsigned char*>(memory_sink_str.c_str()),
memory_sink_str.size(), target_filename) != 0) {
printf("write of patched data to %s failed\n", target_filename.c_str());
return 1;
}
// Delete the backup copy of the source.
unlink(CacheLocation::location().cache_temp_source().c_str());
// Success!
return 0;
}
