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/*
* Copyright 2014 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include <errno.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include "gbb_header.h"
static int is_null_terminated(const char *s, int len)
{
len--;
s += len;
while (len-- >= 0)
if (!*s--)
return 1;
return 0;
}
static inline uint32_t max(uint32_t a, uint32_t b)
{
return a > b ? a : b;
}
int futil_looks_like_gbb(GoogleBinaryBlockHeader *gbb, uint32_t len)
{
if (memcmp(gbb->signature, GBB_SIGNATURE, GBB_SIGNATURE_SIZE))
return 0;
if (gbb->major_version > GBB_MAJOR_VER)
return 0;
if (sizeof(GoogleBinaryBlockHeader) > len)
return 0;
/* close enough */
return 1;
}
int futil_valid_gbb_header(GoogleBinaryBlockHeader *gbb, uint32_t len,
uint32_t *maxlen_ptr)
{
if (memcmp(gbb->signature, GBB_SIGNATURE, GBB_SIGNATURE_SIZE))
return 0;
if (gbb->major_version != GBB_MAJOR_VER)
return 0;
/* Check limits first, to help identify problems */
if (maxlen_ptr) {
uint32_t maxlen = gbb->header_size;
maxlen = max(maxlen,
gbb->hwid_offset + gbb->hwid_size);
maxlen = max(maxlen,
gbb->rootkey_offset + gbb->rootkey_size);
maxlen = max(maxlen,
gbb->bmpfv_offset + gbb->bmpfv_size);
maxlen = max(maxlen,
gbb->recovery_key_offset + gbb->recovery_key_size);
*maxlen_ptr = maxlen;
}
if (gbb->header_size != GBB_HEADER_SIZE || gbb->header_size > len)
return 0;
if (gbb->hwid_offset < GBB_HEADER_SIZE)
return 0;
if (gbb->hwid_offset + gbb->hwid_size > len)
return 0;
if (gbb->hwid_size) {
const char *s = (const char *)
((uint8_t *)gbb + gbb->hwid_offset);
if (!is_null_terminated(s, gbb->hwid_size))
return 0;
}
if (gbb->rootkey_offset < GBB_HEADER_SIZE)
return 0;
if (gbb->rootkey_offset + gbb->rootkey_size > len)
return 0;
if (gbb->bmpfv_offset < GBB_HEADER_SIZE)
return 0;
if (gbb->bmpfv_offset + gbb->bmpfv_size > len)
return 0;
if (gbb->recovery_key_offset < GBB_HEADER_SIZE)
return 0;
if (gbb->recovery_key_offset + gbb->recovery_key_size > len)
return 0;
/* Seems legit... */
return 1;
}
/*
* TODO: All sorts of race conditions likely here, and everywhere this is used.
* Do we care? If so, fix it.
*/
void copy_file_or_die(const char *infile, const char *outfile)
{
pid_t pid;
int status;
pid = fork();
if (pid < 0) {
fprintf(stderr, "Couldn't fork /bin/cp process: %s\n",
strerror(errno));
exit(1);
}
/* child */
if (!pid) {
execl("/bin/cp", "/bin/cp", infile, outfile, NULL);
fprintf(stderr, "Child couldn't exec /bin/cp: %s\n",
strerror(errno));
exit(1);
}
/* parent - wait for child to finish */
if (wait(&status) == -1) {
fprintf(stderr,
"Couldn't wait for /bin/cp process to exit: %s\n",
strerror(errno));
exit(1);
}
if (WIFEXITED(status)) {
status = WEXITSTATUS(status);
/* zero is normal exit */
if (!status)
return;
fprintf(stderr, "/bin/cp exited with status %d\n", status);
exit(1);
}
if (WIFSIGNALED(status)) {
status = WTERMSIG(status);
fprintf(stderr, "/bin/cp was killed with signal %d\n", status);
exit(1);
}
fprintf(stderr, "I have no idea what just happened\n");
exit(1);
}
int map_it(int fd, int writeable, void **buf, uint32_t *len)
{
struct stat sb;
void *mmap_ptr;
uint32_t reasonable_len;
if (0 != fstat(fd, &sb)) {
fprintf(stderr, "Can't stat input file: %s\n",
strerror(errno));
return 1;
}
if (!S_ISREG(sb.st_mode)) {
fprintf(stderr, "Block devices are not yet supported\n");
return 1;
}
/* If the image is larger than 2^32 bytes, it's wrong. */
if (sb.st_size < 0 || sb.st_size > UINT32_MAX) {
fprintf(stderr, "Image size is unreasonable\n");
return 1;
}
reasonable_len = (uint32_t)sb.st_size;
if (writeable)
mmap_ptr = mmap(0, sb.st_size,
PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
else
mmap_ptr = mmap(0, sb.st_size,
PROT_READ, MAP_PRIVATE, fd, 0);
if (mmap_ptr == (void *)-1) {
fprintf(stderr, "Can't mmap %s file: %s\n",
writeable ? "output" : "input",
strerror(errno));
return 1;
}
*buf = mmap_ptr;
*len = reasonable_len;
return 0;
}
int unmap_it(int fd, int writeable, void *buf, uint32_t len)
{
int errorcnt = 0;
if (writeable &&
(0 != msync(buf, len, MS_SYNC|MS_INVALIDATE))) {
fprintf(stderr, "msync failed: %s\n", strerror(errno));
errorcnt++;
}
if (0 != munmap(buf, len)) {
fprintf(stderr, "Can't munmap pointer: %s\n",
strerror(errno));
errorcnt++;
}
return errorcnt;
}
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