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Commit f068272c authored by Bob Copeland's avatar Bob Copeland
Browse files

omfs: check bounds on block numbers before passing to sb_bread 



In case of filesystem corruption, passing unchecked block numbers into
sb_bread can result in an infinite loop in __getblk().  Introduce a wrapper
function omfs_sbread() to check the block numbers and to also perform the
clus_to_blk() scaling.

Signed-off-by: default avatarBob Copeland <me@bobcopeland.com>
parent 70d9e384

fs/omfs/dir.c

+8 −14
Original line number Diff line number Diff line
@@ -25,11 +25,10 @@ static struct buffer_head *omfs_get_bucket(struct inode *dir, 
		const char *name, int namelen, int *ofs)

{

	int nbuckets = (dir->i_size - OMFS_DIR_START)/8;

	int block = clus_to_blk(OMFS_SB(dir->i_sb), dir->i_ino);

	int bucket = omfs_hash(name, namelen, nbuckets);



	*ofs = OMFS_DIR_START + bucket * 8;

	return sb_bread(dir->i_sb, block);

	return omfs_bread(dir->i_sb, dir->i_ino);

}



static struct buffer_head *omfs_scan_list(struct inode *dir, u64 block,
@@ -42,8 +41,7 @@ static struct buffer_head *omfs_scan_list(struct inode *dir, u64 block, 
	*prev_block = ~0;



	while (block != ~0) {

		bh = sb_bread(dir->i_sb,

			clus_to_blk(OMFS_SB(dir->i_sb), block));

		bh = omfs_bread(dir->i_sb, block);

		if (!bh) {

			err = -EIO;

			goto err;
@@ -86,11 +84,10 @@ static struct buffer_head *omfs_find_entry(struct inode *dir, 
int omfs_make_empty(struct inode *inode, struct super_block *sb)

{

	struct omfs_sb_info *sbi = OMFS_SB(sb);

	int block = clus_to_blk(sbi, inode->i_ino);

	struct buffer_head *bh;

	struct omfs_inode *oi;



	bh = sb_bread(sb, block);

	bh = omfs_bread(sb, inode->i_ino);

	if (!bh)

		return -ENOMEM;
@@ -134,7 +131,7 @@ static int omfs_add_link(struct dentry *dentry, struct inode *inode) 
	brelse(bh);



	/* now set the sibling and parent pointers on the new inode */

	bh = sb_bread(dir->i_sb, clus_to_blk(OMFS_SB(dir->i_sb), inode->i_ino));

	bh = omfs_bread(dir->i_sb, inode->i_ino);

	if (!bh)

		goto out;
@@ -190,8 +187,7 @@ static int omfs_delete_entry(struct dentry *dentry) 
	if (prev != ~0) {

		/* found in middle of list, get list ptr */

		brelse(bh);

		bh = sb_bread(dir->i_sb,

			clus_to_blk(OMFS_SB(dir->i_sb), prev));

		bh = omfs_bread(dir->i_sb, prev);

		if (!bh)

			goto out;
@@ -224,8 +220,7 @@ static int omfs_dir_is_empty(struct inode *inode) 
	u64 *ptr;

	int i;



	bh = sb_bread(inode->i_sb, clus_to_blk(OMFS_SB(inode->i_sb),

			inode->i_ino));

	bh = omfs_bread(inode->i_sb, inode->i_ino);



	if (!bh)

		return 0;
@@ -353,8 +348,7 @@ static int omfs_fill_chain(struct file *filp, void *dirent, filldir_t filldir, 


	/* follow chain in this bucket */

	while (fsblock != ~0) {

		bh = sb_bread(dir->i_sb, clus_to_blk(OMFS_SB(dir->i_sb),

				fsblock));

		bh = omfs_bread(dir->i_sb, fsblock);

		if (!bh)

			goto out;
@@ -466,7 +460,7 @@ static int omfs_readdir(struct file *filp, void *dirent, filldir_t filldir) 
	hchain = (filp->f_pos >> 20) - 1;

	hindex = filp->f_pos & 0xfffff;



	bh = sb_bread(dir->i_sb, clus_to_blk(OMFS_SB(dir->i_sb), dir->i_ino));

	bh = omfs_bread(dir->i_sb, dir->i_ino);

	if (!bh)

		goto out;

fs/omfs/file.c

+4 −4
Original line number Diff line number Diff line
@@ -50,7 +50,7 @@ int omfs_shrink_inode(struct inode *inode) 
	if (inode->i_size != 0)

		goto out;



	bh = sb_bread(inode->i_sb, clus_to_blk(sbi, next));

	bh = omfs_bread(inode->i_sb, next);

	if (!bh)

		goto out;
@@ -90,7 +90,7 @@ int omfs_shrink_inode(struct inode *inode) 
		if (next == ~0)

			break;



		bh = sb_bread(inode->i_sb, clus_to_blk(sbi, next));

		bh = omfs_bread(inode->i_sb, next);

		if (!bh)

			goto out;

		oe = (struct omfs_extent *) (&bh->b_data[OMFS_EXTENT_CONT]);
@@ -232,7 +232,7 @@ static int omfs_get_block(struct inode *inode, sector_t block, 
	int remain;



	ret = -EIO;

	bh = sb_bread(inode->i_sb, clus_to_blk(sbi, inode->i_ino));

	bh = omfs_bread(inode->i_sb, inode->i_ino);

	if (!bh)

		goto out;
@@ -265,7 +265,7 @@ static int omfs_get_block(struct inode *inode, sector_t block, 
			break;



		brelse(bh);

		bh = sb_bread(inode->i_sb, clus_to_blk(sbi, next));

		bh = omfs_bread(inode->i_sb, next);

		if (!bh)

			goto out;

		oe = (struct omfs_extent *) (&bh->b_data[OMFS_EXTENT_CONT]);

fs/omfs/inode.c

+16 −11
Original line number Diff line number Diff line
@@ -19,6 +19,15 @@ MODULE_AUTHOR("Bob Copeland <me@bobcopeland.com>"); 
MODULE_DESCRIPTION("OMFS (ReplayTV/Karma) Filesystem for Linux");

MODULE_LICENSE("GPL");



struct buffer_head *omfs_bread(struct super_block *sb, sector_t block)

{

	struct omfs_sb_info *sbi = OMFS_SB(sb);

	if (block >= sbi->s_num_blocks)

		return NULL;



	return sb_bread(sb, clus_to_blk(sbi, block));

}



struct inode *omfs_new_inode(struct inode *dir, int mode)

{

	struct inode *inode;
@@ -93,15 +102,13 @@ static int __omfs_write_inode(struct inode *inode, int wait) 
	struct omfs_inode *oi;

	struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);

	struct buffer_head *bh, *bh2;

	unsigned int block;

	u64 ctime;

	int i;

	int ret = -EIO;

	int sync_failed = 0;



	/* get current inode since we may have written sibling ptrs etc. */

	block = clus_to_blk(sbi, inode->i_ino);

	bh = sb_bread(inode->i_sb, block);

	bh = omfs_bread(inode->i_sb, inode->i_ino);

	if (!bh)

		goto out;
@@ -140,8 +147,7 @@ static int __omfs_write_inode(struct inode *inode, int wait) 


	/* if mirroring writes, copy to next fsblock */

	for (i = 1; i < sbi->s_mirrors; i++) {

		bh2 = sb_bread(inode->i_sb, block + i *

			(sbi->s_blocksize / sbi->s_sys_blocksize));

		bh2 = omfs_bread(inode->i_sb, inode->i_ino + i);

		if (!bh2)

			goto out_brelse;
@@ -193,7 +199,6 @@ struct inode *omfs_iget(struct super_block *sb, ino_t ino) 
	struct omfs_sb_info *sbi = OMFS_SB(sb);

	struct omfs_inode *oi;

	struct buffer_head *bh;

	unsigned int block;

	u64 ctime;

	unsigned long nsecs;

	struct inode *inode;
@@ -204,8 +209,7 @@ struct inode *omfs_iget(struct super_block *sb, ino_t ino) 
	if (!(inode->i_state & I_NEW))

		return inode;



	block = clus_to_blk(sbi, ino);

	bh = sb_bread(inode->i_sb, block);

	bh = omfs_bread(inode->i_sb, ino);

	if (!bh)

		goto iget_failed;
@@ -319,6 +323,9 @@ static int omfs_get_imap(struct super_block *sb) 
		goto nomem;



	block = clus_to_blk(sbi, sbi->s_bitmap_ino);

	if (block >= sbi->s_num_blocks)

		goto nomem;



	ptr = sbi->s_imap;

	for (count = bitmap_size; count > 0; count -= sb->s_blocksize) {

		bh = sb_bread(sb, block++);
@@ -417,7 +424,6 @@ static int omfs_fill_super(struct super_block *sb, void *data, int silent) 
	struct omfs_root_block *omfs_rb;

	struct omfs_sb_info *sbi;

	struct inode *root;

	sector_t start;

	int ret = -EINVAL;



	save_mount_options(sb, (char *) data);
@@ -486,8 +492,7 @@ static int omfs_fill_super(struct super_block *sb, void *data, int silent) 
	sbi->s_block_shift = get_bitmask_order(sbi->s_blocksize) -

		get_bitmask_order(sbi->s_sys_blocksize);



	start = clus_to_blk(sbi, be64_to_cpu(omfs_sb->s_root_block));

	bh2 = sb_bread(sb, start);

	bh2 = omfs_bread(sb, be64_to_cpu(omfs_sb->s_root_block));

	if (!bh2)

		goto out_brelse_bh;

fs/omfs/omfs.h

+1 −0
Original line number Diff line number Diff line
@@ -58,6 +58,7 @@ extern void omfs_make_empty_table(struct buffer_head *bh, int offset); 
extern int omfs_shrink_inode(struct inode *inode);



/* inode.c */

extern struct buffer_head *omfs_bread(struct super_block *sb, sector_t block);

extern struct inode *omfs_iget(struct super_block *sb, ino_t inode);

extern struct inode *omfs_new_inode(struct inode *dir, int mode);

extern int omfs_reserve_block(struct super_block *sb, sector_t block);