blob: 5e33239fd320766c5474ca3bf55f74a982b165f8 [file] [log] [blame]
/*
* e2fuzz.c -- Fuzz an ext4 image, for testing purposes.
*
* Copyright (C) 2014 Oracle.
*
* %Begin-Header%
* This file may be redistributed under the terms of the GNU Library
* General Public License, version 2.
* %End-Header%
*/
#define _XOPEN_SOURCE 600
#define _FILE_OFFSET_BITS 64
#define _LARGEFILE64_SOURCE 1
#define _GNU_SOURCE 1
#include "config.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdint.h>
#include <unistd.h>
#ifdef HAVE_GETOPT_H
#include <getopt.h>
#endif
#include "ext2fs/ext2_fs.h"
#include "ext2fs/ext2fs.h"
static int dryrun = 0;
static int verbose = 0;
static int metadata_only = 1;
static unsigned long long user_corrupt_bytes = 0;
static double user_corrupt_pct = 0.0;
#if !defined HAVE_PWRITE64 && !defined HAVE_PWRITE
static ssize_t my_pwrite(int fd, const void *buf, size_t count, off_t offset)
{
if (lseek(fd, offset, SEEK_SET) < 0)
return 0;
return write(fd, buf, count);
}
#endif /* !defined HAVE_PWRITE64 && !defined HAVE_PWRITE */
static int getseed(void)
{
int r;
int fd;
fd = open("/dev/urandom", O_RDONLY);
if (fd < 0) {
perror("open");
exit(0);
}
if (read(fd, &r, sizeof(r)) != sizeof(r))
printf("Unable to read random seed!\n");
close(fd);
return r;
}
struct find_block {
ext2_ino_t ino;
ext2fs_block_bitmap bmap;
struct ext2_inode *inode;
blk64_t corrupt_blocks;
};
static int find_block_helper(ext2_filsys fs EXT2FS_ATTR((unused)),
blk64_t *blocknr, e2_blkcnt_t blockcnt,
blk64_t ref_blk EXT2FS_ATTR((unused)),
int ref_offset EXT2FS_ATTR((unused)),
void *priv_data)
{
struct find_block *fb = (struct find_block *)priv_data;
if (S_ISDIR(fb->inode->i_mode) || !metadata_only || blockcnt < 0) {
ext2fs_mark_block_bitmap2(fb->bmap, *blocknr);
fb->corrupt_blocks++;
}
return 0;
}
static errcode_t find_metadata_blocks(ext2_filsys fs, ext2fs_block_bitmap bmap,
off_t *corrupt_bytes)
{
dgrp_t i;
blk64_t b, c;
ext2_inode_scan scan;
ext2_ino_t ino;
struct ext2_inode inode;
struct find_block fb;
errcode_t retval;
*corrupt_bytes = 0;
fb.corrupt_blocks = 0;
/* Construct bitmaps of super/descriptor blocks */
for (i = 0; i < fs->group_desc_count; i++) {
ext2fs_reserve_super_and_bgd(fs, i, bmap);
/* bitmaps and inode table */
b = ext2fs_block_bitmap_loc(fs, i);
ext2fs_mark_block_bitmap2(bmap, b);
fb.corrupt_blocks++;
b = ext2fs_inode_bitmap_loc(fs, i);
ext2fs_mark_block_bitmap2(bmap, b);
fb.corrupt_blocks++;
c = ext2fs_inode_table_loc(fs, i);
ext2fs_mark_block_bitmap_range2(bmap, c,
fs->inode_blocks_per_group);
fb.corrupt_blocks += fs->inode_blocks_per_group;
}
/* Scan inodes */
fb.bmap = bmap;
fb.inode = &inode;
memset(&inode, 0, sizeof(inode));
retval = ext2fs_open_inode_scan(fs, 0, &scan);
if (retval)
goto out;
retval = ext2fs_get_next_inode_full(scan, &ino, &inode, sizeof(inode));
if (retval)
goto out2;
while (ino) {
if (inode.i_links_count == 0)
goto next_loop;
b = ext2fs_file_acl_block(fs, &inode);
if (b) {
ext2fs_mark_block_bitmap2(bmap, b);
fb.corrupt_blocks++;
}
/*
* Inline data, sockets, devices, and symlinks have
* no blocks to iterate.
*/
if ((inode.i_flags & EXT4_INLINE_DATA_FL) ||
S_ISLNK(inode.i_mode) || S_ISFIFO(inode.i_mode) ||
S_ISCHR(inode.i_mode) || S_ISBLK(inode.i_mode) ||
S_ISSOCK(inode.i_mode))
goto next_loop;
fb.ino = ino;
retval = ext2fs_block_iterate3(fs, ino, BLOCK_FLAG_READ_ONLY,
NULL, find_block_helper, &fb);
if (retval)
goto out2;
next_loop:
retval = ext2fs_get_next_inode_full(scan, &ino, &inode,
sizeof(inode));
if (retval)
goto out2;
}
out2:
ext2fs_close_inode_scan(scan);
out:
if (!retval)
*corrupt_bytes = fb.corrupt_blocks * fs->blocksize;
return retval;
}
static uint64_t rand_num(uint64_t min, uint64_t max)
{
uint64_t x;
unsigned int i;
uint8_t *px = (uint8_t *)&x;
for (i = 0; i < sizeof(x); i++)
px[i] = random();
return min + (uint64_t)((double)(max - min) * (x / (UINT64_MAX + 1.0)));
}
static int process_fs(const char *fsname)
{
errcode_t ret;
int flags, fd;
ext2_filsys fs = NULL;
ext2fs_block_bitmap corrupt_map;
off_t hsize, count, off, offset, corrupt_bytes;
unsigned char c;
off_t i;
/* If mounted rw, force dryrun mode */
ret = ext2fs_check_if_mounted(fsname, &flags);
if (ret) {
fprintf(stderr, "%s: failed to determine filesystem mount "
"state.\n", fsname);
return 1;
}
if (!dryrun && (flags & EXT2_MF_MOUNTED) &&
!(flags & EXT2_MF_READONLY)) {
fprintf(stderr, "%s: is mounted rw, performing dry run.\n",
fsname);
dryrun = 1;
}
/* Ensure the fs is clean and does not have errors */
ret = ext2fs_open(fsname, EXT2_FLAG_64BITS, 0, 0, unix_io_manager,
&fs);
if (ret) {
fprintf(stderr, "%s: failed to open filesystem.\n",
fsname);
return 1;
}
if ((fs->super->s_state & EXT2_ERROR_FS)) {
fprintf(stderr, "%s: errors detected, run fsck.\n",
fsname);
goto fail;
}
if (!dryrun && (fs->super->s_state & EXT2_VALID_FS) == 0) {
fprintf(stderr, "%s: unclean shutdown, performing dry run.\n",
fsname);
dryrun = 1;
}
/* Construct a bitmap of whatever we're corrupting */
if (!metadata_only) {
/* Load block bitmap */
ret = ext2fs_read_block_bitmap(fs);
if (ret) {
fprintf(stderr, "%s: error while reading block bitmap\n",
fsname);
goto fail;
}
corrupt_map = fs->block_map;
corrupt_bytes = (ext2fs_blocks_count(fs->super) -
ext2fs_free_blocks_count(fs->super)) *
fs->blocksize;
} else {
ret = ext2fs_allocate_block_bitmap(fs, "metadata block map",
&corrupt_map);
if (ret) {
fprintf(stderr, "%s: unable to create block bitmap\n",
fsname);
goto fail;
}
/* Iterate everything... */
ret = find_metadata_blocks(fs, corrupt_map, &corrupt_bytes);
if (ret) {
fprintf(stderr, "%s: while finding metadata\n",
fsname);
goto fail;
}
}
/* Run around corrupting things */
fd = open(fsname, O_RDWR);
if (fd < 0) {
perror(fsname);
goto fail;
}
srandom(getseed());
hsize = fs->blocksize * ext2fs_blocks_count(fs->super);
if (user_corrupt_bytes > 0)
count = user_corrupt_bytes;
else if (user_corrupt_pct > 0.0)
count = user_corrupt_pct * corrupt_bytes / 100;
else
count = rand_num(0, corrupt_bytes / 100);
offset = 4096; /* never corrupt superblock */
for (i = 0; i < count; i++) {
do
off = rand_num(offset, hsize);
while (!ext2fs_test_block_bitmap2(corrupt_map,
off / fs->blocksize));
c = rand() % 256;
if ((rand() % 2) && c < 128)
c |= 0x80;
if (verbose)
printf("Corrupting byte %zu in block %zu to 0x%x\n",
off % fs->blocksize, off / fs->blocksize, c);
if (dryrun)
continue;
#ifdef HAVE_PWRITE64
if (pwrite64(fd, &c, sizeof(c), off) != sizeof(c)) {
perror(fsname);
goto fail3;
}
#elif HAVE_PWRITE
if (pwrite(fd, &c, sizeof(c), off) != sizeof(c)) {
perror(fsname);
goto fail3;
}
#else
if (my_pwrite(fd, &c, sizeof(c), off) != sizeof(c)) {
perror(fsname);
goto fail3;
}
#endif
}
close(fd);
/* Clean up */
ret = ext2fs_close_free(&fs);
if (ret) {
fprintf(stderr, "%s: error while closing filesystem\n",
fsname);
return 1;
}
return 0;
fail3:
close(fd);
if (corrupt_map != fs->block_map)
ext2fs_free_block_bitmap(corrupt_map);
fail:
ext2fs_close_free(&fs);
return 1;
}
static void print_help(const char *progname)
{
printf("Usage: %s OPTIONS device\n", progname);
printf("-b: Corrupt this many bytes.\n");
printf("-d: Fuzz data blocks too.\n");
printf("-n: Dry run only.\n");
printf("-v: Verbose output.\n");
exit(0);
}
int main(int argc, char *argv[])
{
int c;
while ((c = getopt(argc, argv, "b:dnv")) != -1) {
switch (c) {
case 'b':
if (optarg[strlen(optarg) - 1] == '%') {
user_corrupt_pct = strtod(optarg, NULL);
if (user_corrupt_pct > 100 ||
user_corrupt_pct < 0) {
fprintf(stderr, "%s: Invalid percentage.\n",
optarg);
return 1;
}
} else
user_corrupt_bytes = strtoull(optarg, NULL, 0);
if (errno) {
perror(optarg);
return 1;
}
break;
case 'd':
metadata_only = 0;
break;
case 'n':
dryrun = 1;
break;
case 'v':
verbose = 1;
break;
default:
print_help(argv[0]);
}
}
for (c = optind; c < argc; c++)
if (process_fs(argv[c]))
return 1;
return 0;
}