/*
* Copyright (C) 2007 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 <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <unistd.h>
#include <string.h>
#include <stdio.h>
#include "common.h"
#include "twmincrypt/twrsa.h"
#include "twmincrypt/twsha.h"
#include "minui/minui.h"
#include "minzip/SysUtil.h"
#include "minzip/Zip.h"
#include "mtdutils/mounts.h"
#include "mtdutils/mtdutils.h"
#include "roots.h"
#include "verifier.h"
#include "ui.h"
#include "variables.h"
#include "data.hpp"
#include "partitions.hpp"
extern "C" {
#include "extra-functions.h"
int __system(const char *command);
};
extern RecoveryUI* ui;
#define ASSUMED_UPDATE_BINARY_NAME "META-INF/com/google/android/update-binary"
#define PUBLIC_KEYS_FILE "/res/keys"
// Default allocation of progress bar segments to operations
static const int VERIFICATION_PROGRESS_TIME = 60;
static const float VERIFICATION_PROGRESS_FRACTION = 0.25;
static const float DEFAULT_FILES_PROGRESS_FRACTION = 0.4;
static const float DEFAULT_IMAGE_PROGRESS_FRACTION = 0.1;
enum { INSTALL_SUCCESS, INSTALL_ERROR, INSTALL_CORRUPT };
// Look for an RSA signature embedded in the .ZIP file comment given
// the path to the zip. Verify it matches one of the given public
// keys.
//
// Return VERIFY_SUCCESS, VERIFY_FAILURE (if any error is encountered
// or no key matches the signature).
int TWverify_file(const char* path, const RSAPublicKey *pKeys, unsigned int numKeys) {
ui->SetProgress(0.0);
FILE* f = fopen(path, "rb");
if (f == NULL) {
LOGE("failed to open %s (%s)\n", path, strerror(errno));
return VERIFY_FAILURE;
}
// An archive with a whole-file signature will end in six bytes:
//
// (2-byte signature start) $ff $ff (2-byte comment size)
//
// (As far as the ZIP format is concerned, these are part of the
// archive comment.) We start by reading this footer, this tells
// us how far back from the end we have to start reading to find
// the whole comment.
#define FOOTER_SIZE 6
if (fseek(f, -FOOTER_SIZE, SEEK_END) != 0) {
LOGE("failed to seek in %s (%s)\n", path, strerror(errno));
fclose(f);
return VERIFY_FAILURE;
}
unsigned char footer[FOOTER_SIZE];
if (fread(footer, 1, FOOTER_SIZE, f) != FOOTER_SIZE) {
LOGE("failed to read footer from %s (%s)\n", path, strerror(errno));
fclose(f);
return VERIFY_FAILURE;
}
if (footer[2] != 0xff || footer[3] != 0xff) {
fclose(f);
return VERIFY_FAILURE;
}
size_t comment_size = footer[4] + (footer[5] << 8);
size_t signature_start = footer[0] + (footer[1] << 8);
LOGI("comment is %d bytes; signature %d bytes from end\n",
comment_size, signature_start);
if (signature_start - FOOTER_SIZE < RSANUMBYTES) {
// "signature" block isn't big enough to contain an RSA block.
LOGE("signature is too short\n");
fclose(f);
return VERIFY_FAILURE;
}
#define EOCD_HEADER_SIZE 22
// The end-of-central-directory record is 22 bytes plus any
// comment length.
size_t eocd_size = comment_size + EOCD_HEADER_SIZE;
if (fseek(f, -eocd_size, SEEK_END) != 0) {
LOGE("failed to seek in %s (%s)\n", path, strerror(errno));
fclose(f);
return VERIFY_FAILURE;
}
// Determine how much of the file is covered by the signature.
// This is everything except the signature data and length, which
// includes all of the EOCD except for the comment length field (2
// bytes) and the comment data.
size_t signed_len = ftell(f) + EOCD_HEADER_SIZE - 2;
unsigned char* eocd = (unsigned char*)malloc(eocd_size);
if (eocd == NULL) {
LOGE("malloc for EOCD record failed\n");
fclose(f);
return VERIFY_FAILURE;
}
if (fread(eocd, 1, eocd_size, f) != eocd_size) {
LOGE("failed to read eocd from %s (%s)\n", path, strerror(errno));
fclose(f);
return VERIFY_FAILURE;
}
// If this is really is the EOCD record, it will begin with the
// magic number $50 $4b $05 $06.
if (eocd[0] != 0x50 || eocd[1] != 0x4b ||
eocd[2] != 0x05 || eocd[3] != 0x06) {
LOGE("signature length doesn't match EOCD marker\n");
fclose(f);
return VERIFY_FAILURE;
}
size_t i;
for (i = 4; i < eocd_size-3; ++i) {
if (eocd[i ] == 0x50 && eocd[i+1] == 0x4b &&
eocd[i+2] == 0x05 && eocd[i+3] == 0x06) {
// if the sequence $50 $4b $05 $06 appears anywhere after
// the real one, minzip will find the later (wrong) one,
// which could be exploitable. Fail verification if
// this sequence occurs anywhere after the real one.
LOGE("EOCD marker occurs after start of EOCD\n");
fclose(f);
return VERIFY_FAILURE;
}
}
#define BUFFER_SIZE 4096
SHA_CTX ctx;
SHA_init(&ctx);
unsigned char* buffer = (unsigned char*)malloc(BUFFER_SIZE);
if (buffer == NULL) {
LOGE("failed to alloc memory for sha1 buffer\n");
fclose(f);
return VERIFY_FAILURE;
}
double frac = -1.0;
size_t so_far = 0;
fseek(f, 0, SEEK_SET);
while (so_far < signed_len) {
size_t size = BUFFER_SIZE;
if (signed_len - so_far < size) size = signed_len - so_far;
if (fread(buffer, 1, size, f) != size) {
LOGE("failed to read data from %s (%s)\n", path, strerror(errno));
fclose(f);
return VERIFY_FAILURE;
}
SHA_update(&ctx, buffer, size);
so_far += size;
double f = so_far / (double)signed_len;
if (f > frac + 0.02 || size == so_far) {
ui->SetProgress(f);
frac = f;
}
}
fclose(f);
free(buffer);
const uint8_t* sha1 = SHA_final(&ctx);
for (i = 0; i < numKeys; ++i) {
// The 6 bytes is the "(signature_start) $ff $ff (comment_size)" that
// the signing tool appends after the signature itself.
if (RSA_verify(pKeys+i, eocd + eocd_size - 6 - RSANUMBYTES,
RSANUMBYTES, sha1)) {
LOGI("whole-file signature verified against key %d\n", i);
free(eocd);
return VERIFY_SUCCESS;
}
}
free(eocd);
LOGE("failed to verify whole-file signature\n");
return VERIFY_FAILURE;
}
// If the package contains an update binary, extract it and run it.
static int
try_update_binary(const char *path, ZipArchive *zip, int* wipe_cache) {
const ZipEntry* binary_entry =
mzFindZipEntry(zip, ASSUMED_UPDATE_BINARY_NAME);
if (binary_entry == NULL) {
mzCloseZipArchive(zip);
return INSTALL_CORRUPT;
}
const char* binary = "/tmp/update_binary";
unlink(binary);
int fd = creat(binary, 0755);
if (fd < 0) {
mzCloseZipArchive(zip);
LOGE("Can't make %s\n", binary);
return INSTALL_ERROR;
}
bool ok = mzExtractZipEntryToFile(zip, binary_entry, fd);
close(fd);
mzCloseZipArchive(zip);
if (!ok) {
LOGE("Can't copy %s\n", ASSUMED_UPDATE_BINARY_NAME);
return INSTALL_ERROR;
}
int pipefd[2];
pipe(pipefd);
// When executing the update binary contained in the package, the
// arguments passed are:
//
// - the version number for this interface
//
// - an fd to which the program can write in order to update the
// progress bar. The program can write single-line commands:
//
// progress <frac> <secs>
// fill up the next <frac> part of of the progress bar
// over <secs> seconds. If <secs> is zero, use
// set_progress commands to manually control the
// progress of this segment of the bar
//
// set_progress <frac>
// <frac> should be between 0.0 and 1.0; sets the
// progress bar within the segment defined by the most
// recent progress command.
//
// firmware <"hboot"|"radio"> <filename>
// arrange to install the contents of <filename> in the
// given partition on reboot.
//
// (API v2: <filename> may start with "PACKAGE:" to
// indicate taking a file from the OTA package.)
//
// (API v3: this command no longer exists.)
//
// ui_print <string>
// display <string> on the screen.
//
// - the name of the package zip file.
//
const char** args = (const char**)malloc(sizeof(char*) * 5);
args[0] = binary;
args[1] = EXPAND(RECOVERY_API_VERSION); // defined in Android.mk
char* temp = (char*)malloc(10);
sprintf(temp, "%d", pipefd[1]);
args[2] = temp;
args[3] = (char*)path;
args[4] = NULL;
pid_t pid = fork();
if (pid == 0) {
close(pipefd[0]);
execv(binary, (char* const*)args);
fprintf(stdout, "E:Can't run %s (%s)\n", binary, strerror(errno));
_exit(-1);
}
close(pipefd[1]);
*wipe_cache = 0;
char buffer[1024];
FILE* from_child = fdopen(pipefd[0], "r");
while (fgets(buffer, sizeof(buffer), from_child) != NULL) {
char* command = strtok(buffer, " \n");
if (command == NULL) {
continue;
} else if (strcmp(command, "progress") == 0) {
char* fraction_s = strtok(NULL, " \n");
char* seconds_s = strtok(NULL, " \n");
float fraction = strtof(fraction_s, NULL);
int seconds = strtol(seconds_s, NULL, 10);
ui->ShowProgress(fraction * (1-VERIFICATION_PROGRESS_FRACTION), seconds);
} else if (strcmp(command, "set_progress") == 0) {
char* fraction_s = strtok(NULL, " \n");
float fraction = strtof(fraction_s, NULL);
ui->SetProgress(fraction);
} else if (strcmp(command, "ui_print") == 0) {
char* str = strtok(NULL, "\n");
if (str) {
ui->Print("%s", str);
} else {
ui->Print("\n");
}
} else if (strcmp(command, "wipe_cache") == 0) {
*wipe_cache = 1;
} else if (strcmp(command, "clear_display") == 0) {
//ui->SetBackground(RecoveryUI::NONE);
} else {
LOGE("unknown command [%s]\n", command);
}
}
fclose(from_child);
int status;
waitpid(pid, &status, 0);
if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
LOGE("Error in %s\n(Status %d)\n", path, WEXITSTATUS(status));
return INSTALL_ERROR;
}
return INSTALL_SUCCESS;
}
// Reads a file containing one or more public keys as produced by
// DumpPublicKey: this is an RSAPublicKey struct as it would appear
// as a C source literal, eg:
//
// "{64,0xc926ad21,{1795090719,...,-695002876},{-857949815,...,1175080310}}"
//
// (Note that the braces and commas in this example are actual
// characters the parser expects to find in the file; the ellipses
// indicate more numbers omitted from this example.)
//
// The file may contain multiple keys in this format, separated by
// commas. The last key must not be followed by a comma.
//
// Returns NULL if the file failed to parse, or if it contain zero keys.
static RSAPublicKey*
load_keys(const char* filename, int* numKeys) {
RSAPublicKey* out = NULL;
*numKeys = 0;
FILE* f = fopen(filename, "r");
if (f == NULL) {
LOGE("opening %s: %s\n", filename, strerror(errno));
goto exit;
}
{
int i;
bool done = false;
while (!done) {
++*numKeys;
out = (RSAPublicKey*)realloc(out, *numKeys * sizeof(RSAPublicKey));
RSAPublicKey* key = out + (*numKeys - 1);
if (fscanf(f, " { %i , 0x%x , { %u",
&(key->len), &(key->n0inv), &(key->n[0])) != 3) {
goto exit;
}
if (key->len != RSANUMWORDS) {
LOGE("key length (%d) does not match expected size\n", key->len);
goto exit;
}
for (i = 1; i < key->len; ++i) {
if (fscanf(f, " , %u", &(key->n[i])) != 1) goto exit;
}
if (fscanf(f, " } , { %u", &(key->rr[0])) != 1) goto exit;
for (i = 1; i < key->len; ++i) {
if (fscanf(f, " , %u", &(key->rr[i])) != 1) goto exit;
}
fscanf(f, " } } ");
// if the line ends in a comma, this file has more keys.
switch (fgetc(f)) {
case ',':
// more keys to come.
break;
case EOF:
done = true;
break;
default:
LOGE("unexpected character between keys\n");
goto exit;
}
}
}
fclose(f);
return out;
exit:
if (f) fclose(f);
free(out);
*numKeys = 0;
return NULL;
}
char* get_path (char* path) {
char *s;
/* Go to the end of the string. */
s = path + strlen(path) - 1;
/* Strip off trailing /s (unless it is also the leading /). */
while (path < s && s[0] == '/')
s--;
/* Strip the last component. */
while (path <= s && s[0] != '/')
s--;
while (path < s && s[0] == '/')
s--;
if (s < path)
return (char*)(".");
s[1] = '\0';
return path;
}
/*
Checks md5 for a path
Return values:
-1 : MD5 does not exist
0 : Failed
1 : Success
*/
int check_md5(const char* path) {
FILE* fp;
char command[255], line[512], actual_md5[512], md5[512];
char md5file[PATH_MAX + 40];
char *ptr;
unsigned int line_len, index = 0;
struct stat st;
// Check to see if the filename.zip.md5 file exists
strcpy(md5file, path);
strcat(md5file, ".md5");
if (stat(md5file, &st) != 0)
return -1; // no MD5 file found
// Dump the md5 of the zip to a text file for reading
sprintf(command, "md5sum '%s' > /tmp/md5output.txt", path);
__system(command);
fp = fopen("/tmp/md5output.txt", "rt");
if (fp == NULL) {
LOGI("Unable to open /tmp/md5output.txt.\n");
return false;
}
while (fgets(line, sizeof(line), fp) != NULL)
{
line_len = strlen(line);
for (index = 0; index < line_len; index++) {
if (line[index] <= 32)
line[index] = '\0';
}
strcpy(actual_md5, line);
break;
}
fclose(fp);
// Read the filename.zip.md5 file
fp = fopen(md5file, "rt");
if (fp == NULL) {
LOGI("Unable to open '%s'.\n", md5file);
return false;
}
while (fgets(line, sizeof(line), fp) != NULL)
{
line_len = strlen(line);
for (index = 0; index < line_len; index++) {
if (line[index] <= 32)
line[index] = '\0';
}
strcpy(md5, line);
break;
}
fclose(fp);
// Comare the 2 MD5 values
if (strcmp(actual_md5, md5) == 0)
return 1;
LOGI("MD5 did not match: '%s' != '%s'\n", actual_md5, md5);
return 0;
}
extern "C" int TWinstall_zip(const char* path, int* wipe_cache) {
int err, zip_verify, md5_return, md5_verify;
ui_print("Installing '%s'...\n", path);
if (!PartitionManager.Mount_By_Path(path, 0)) {
LOGE("Failed to mount '%s'\n", path);
return -1;
}
ui_print("Checking for MD5 file...\n");
md5_return = check_md5(path);
if (md5_return == 0) {
// MD5 did not match.
LOGE("Zip MD5 does not match.\nUnable to install zip.\n");
return INSTALL_CORRUPT;
} else if (md5_return == -1) {
DataManager::GetValue(TW_FORCE_MD5_CHECK_VAR, md5_verify);
if (md5_verify == 1) {
// Forced MD5 checking is on and no MD5 file found.
LOGE("No MD5 file found for '%s'.\nDisable force MD5 check to avoid this error.\n", path);
return INSTALL_CORRUPT;
} else
ui_print("No MD5 file found, this is not an error.\n");
} else if (md5_return == 1)
ui_print("Zip MD5 matched.\n"); // MD5 found and matched.
DataManager::GetValue(TW_SIGNED_ZIP_VERIFY_VAR, zip_verify);
if (zip_verify) {
ui_print("Verifying zip signature...\n");
int numKeys;
RSAPublicKey* loadedKeys = load_keys(PUBLIC_KEYS_FILE, &numKeys);
if (loadedKeys == NULL) {
LOGE("Failed to load keys\n");
return -1;
}
LOGI("%d key(s) loaded from %s\n", numKeys, PUBLIC_KEYS_FILE);
// Give verification half the progress bar...
ui->Print("Verifying update package...\n");
ui->SetProgressType(RecoveryUI::DETERMINATE);
ui->ShowProgress(VERIFICATION_PROGRESS_FRACTION, VERIFICATION_PROGRESS_TIME);
err = TWverify_file(path, loadedKeys, numKeys);
free(loadedKeys);
LOGI("verify_file returned %d\n", err);
if (err != VERIFY_SUCCESS) {
LOGE("signature verification failed\n");
return -1;
}
}
/* Try to open the package.
*/
ZipArchive zip;
err = mzOpenZipArchive(path, &zip);
if (err != 0) {
LOGE("Can't open %s\n(%s)\n", path, err != -1 ? strerror(err) : "bad");
return INSTALL_CORRUPT;
}
/* Verify and install the contents of the package.
*/
return try_update_binary(path, &zip, wipe_cache);
}
