1 files changed, 372 insertions, 0 deletions

diff --git a/misc/e2fuzz.c b/misc/e2fuzz.c
new file mode 100644
index 0000000..0ceece9
--- /dev/null
+++ b/misc/e2fuzz.c
@@ -0,0 +1,372 @@
+/*
+ * 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,
+			 ext2_loff_t offset)
+{
+	if (ext2fs_llseek(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,
+				      ext2_loff_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 / ((double) 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;
+	ext2_loff_t hsize, count, off, offset, corrupt_bytes, i;
+	unsigned char c;
+
+	/* 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 | EXT2_FLAG_THREADS,
+			  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 %lld in block %lld 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;
+}