From e6c4021190c828d7fa24a464db589f86c6708341 Mon Sep 17 00:00:00 2001 From: Eric Sandeen Date: Wed, 6 Dec 2006 20:36:28 -0800 Subject: [PATCH] handle ext4 directory corruption better I've been using Steve Grubb's purely evil "fsfuzzer" tool, at http://people.redhat.com/sgrubb/files/fsfuzzer-0.4.tar.gz Basically it makes a filesystem, splats some random bits over it, then tries to mount it and do some simple filesystem actions. At best, the filesystem catches the corruption gracefully. At worst, things spin out of control. As you might guess, we found a couple places in ext4 where things spin out of control :) First, we had a corrupted directory that was never checked for consistency... it was corrupt, and pointed to another bad "entry" of length 0. The for() loop looped forever, since the length of ext4_next_entry(de) was 0, and we kept looking at the same pointer over and over and over and over... I modeled this check and subsequent action on what is done for other directory types in ext4_readdir... (adding this check adds some computational expense; I am testing a followup patch to reduce the number of times we check and re-check these directory entries, in all cases. Thanks for the idea, Andreas). Next we had a root directory inode which had a corrupted size, claimed to be > 200M on a 4M filesystem. There was only really 1 block in the directory, but because the size was so large, readdir kept coming back for more, spewing thousands of printk's along the way. Per Andreas' suggestion, if we're in this read error condition and we're trying to read an offset which is greater than i_blocks worth of bytes, stop trying, and break out of the loop. With these two changes fsfuzz test survives quite well on ext4. Signed-off-by: Eric Sandeen Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ext4/namei.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'fs/ext4/namei.c') diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index 8b1bd03d20f..859990eac50 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -552,6 +552,15 @@ static int htree_dirblock_to_tree(struct file *dir_file, dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(0)); for (; de < top; de = ext4_next_entry(de)) { + if (!ext4_check_dir_entry("htree_dirblock_to_tree", dir, de, bh, + (block<i_sb)) + +((char *)de - bh->b_data))) { + /* On error, skip the f_pos to the next block. */ + dir_file->f_pos = (dir_file->f_pos | + (dir->i_sb->s_blocksize - 1)) + 1; + brelse (bh); + return count; + } ext4fs_dirhash(de->name, de->name_len, hinfo); if ((hinfo->hash < start_hash) || ((hinfo->hash == start_hash) && -- cgit v1.2.3-70-g09d2 From 9d549890e69156800878a486f832e92d8f3d7c97 Mon Sep 17 00:00:00 2001 From: "Josef \"Jeff\" Sipek" Date: Fri, 8 Dec 2006 02:36:38 -0800 Subject: [PATCH] ext4: change uses of f_{dentry, vfsmnt} to use f_path Change all the uses of f_{dentry,vfsmnt} to f_path.{dentry,mnt} in the ext4 filesystem. Signed-off-by: Josef "Jeff" Sipek Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ext4/dir.c | 8 ++++---- fs/ext4/file.c | 2 +- fs/ext4/ioctl.c | 2 +- fs/ext4/namei.c | 4 ++-- 4 files changed, 8 insertions(+), 8 deletions(-) (limited to 'fs/ext4/namei.c') diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c index f2ed3e7fb9f..da80368b66f 100644 --- a/fs/ext4/dir.c +++ b/fs/ext4/dir.c @@ -103,7 +103,7 @@ static int ext4_readdir(struct file * filp, struct ext4_dir_entry_2 *de; struct super_block *sb; int err; - struct inode *inode = filp->f_dentry->d_inode; + struct inode *inode = filp->f_path.dentry->d_inode; int ret = 0; sb = inode->i_sb; @@ -122,7 +122,7 @@ static int ext4_readdir(struct file * filp, * We don't set the inode dirty flag since it's not * critical that it get flushed back to the disk. */ - EXT4_I(filp->f_dentry->d_inode)->i_flags &= ~EXT4_INDEX_FL; + EXT4_I(filp->f_path.dentry->d_inode)->i_flags &= ~EXT4_INDEX_FL; } #endif stored = 0; @@ -402,7 +402,7 @@ static int call_filldir(struct file * filp, void * dirent, { struct dir_private_info *info = filp->private_data; loff_t curr_pos; - struct inode *inode = filp->f_dentry->d_inode; + struct inode *inode = filp->f_path.dentry->d_inode; struct super_block * sb; int error; @@ -432,7 +432,7 @@ static int ext4_dx_readdir(struct file * filp, void * dirent, filldir_t filldir) { struct dir_private_info *info = filp->private_data; - struct inode *inode = filp->f_dentry->d_inode; + struct inode *inode = filp->f_path.dentry->d_inode; struct fname *fname; int ret; diff --git a/fs/ext4/file.c b/fs/ext4/file.c index 0b622c0624b..3bbc24b5878 100644 --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -52,7 +52,7 @@ ext4_file_write(struct kiocb *iocb, const struct iovec *iov, unsigned long nr_segs, loff_t pos) { struct file *file = iocb->ki_filp; - struct inode *inode = file->f_dentry->d_inode; + struct inode *inode = file->f_path.dentry->d_inode; ssize_t ret; int err; diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c index 22a737c306c..500567dd53b 100644 --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -256,7 +256,7 @@ flags_err: #ifdef CONFIG_COMPAT long ext4_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { - struct inode *inode = file->f_dentry->d_inode; + struct inode *inode = file->f_path.dentry->d_inode; int ret; /* These are just misnamed, they actually get/put from/to user an int */ diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index 859990eac50..e5a74a5ac26 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -602,7 +602,7 @@ int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash, dxtrace(printk("In htree_fill_tree, start hash: %x:%x\n", start_hash, start_minor_hash)); - dir = dir_file->f_dentry->d_inode; + dir = dir_file->f_path.dentry->d_inode; if (!(EXT4_I(dir)->i_flags & EXT4_INDEX_FL)) { hinfo.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version; hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed; @@ -613,7 +613,7 @@ int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash, } hinfo.hash = start_hash; hinfo.minor_hash = 0; - frame = dx_probe(NULL, dir_file->f_dentry->d_inode, &hinfo, frames, &err); + frame = dx_probe(NULL, dir_file->f_path.dentry->d_inode, &hinfo, frames, &err); if (!frame) return err; -- cgit v1.2.3-70-g09d2