From: Theodore Ts'o tytso@mit.edu
commit 4b3cb1d108bfc2aebb0d7c8a52261a53cf7f5786 upstream.
The ext4_dirhash() will *almost* never fail, especially when the hash tree feature was first introduced. However, with the addition of support of encrypted, casefolded file names, that function can most certainly fail today.
So make sure the callers of ext4_dirhash() properly check for failures, and reflect the errors back up to their callers.
Cc: stable@kernel.org Link: https://lore.kernel.org/r/20230506142419.984260-1-tytso@mit.edu Reported-by: syzbot+394aa8a792cb99dbc837@syzkaller.appspotmail.com Reported-by: syzbot+344aaa8697ebd232bfc8@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?id=db56459ea4ac4a676ae4b4678f633e55da005a9... Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/ext4/hash.c | 6 +++++- fs/ext4/namei.c | 53 +++++++++++++++++++++++++++++++++++++---------------- 2 files changed, 42 insertions(+), 17 deletions(-)
--- a/fs/ext4/hash.c +++ b/fs/ext4/hash.c @@ -277,7 +277,11 @@ static int __ext4fs_dirhash(const struct } default: hinfo->hash = 0; - return -1; + hinfo->minor_hash = 0; + ext4_warning(dir->i_sb, + "invalid/unsupported hash tree version %u", + hinfo->hash_version); + return -EINVAL; } hash = hash & ~1; if (hash == (EXT4_HTREE_EOF_32BIT << 1)) --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -674,7 +674,7 @@ static struct stats dx_show_leaf(struct len = de->name_len; if (!IS_ENCRYPTED(dir)) { /* Directory is not encrypted */ - ext4fs_dirhash(dir, de->name, + (void) ext4fs_dirhash(dir, de->name, de->name_len, &h); printk("%*.s:(U)%x.%u ", len, name, h.hash, @@ -709,8 +709,9 @@ static struct stats dx_show_leaf(struct if (IS_CASEFOLDED(dir)) h.hash = EXT4_DIRENT_HASH(de); else - ext4fs_dirhash(dir, de->name, - de->name_len, &h); + (void) ext4fs_dirhash(dir, + de->name, + de->name_len, &h); printk("%*.s:(E)%x.%u ", len, name, h.hash, (unsigned) ((char *) de - base)); @@ -720,7 +721,8 @@ static struct stats dx_show_leaf(struct #else int len = de->name_len; char *name = de->name; - ext4fs_dirhash(dir, de->name, de->name_len, &h); + (void) ext4fs_dirhash(dir, de->name, + de->name_len, &h); printk("%*.s:%x.%u ", len, name, h.hash, (unsigned) ((char *) de - base)); #endif @@ -849,8 +851,14 @@ dx_probe(struct ext4_filename *fname, st hinfo->seed = EXT4_SB(dir->i_sb)->s_hash_seed; /* hash is already computed for encrypted casefolded directory */ if (fname && fname_name(fname) && - !(IS_ENCRYPTED(dir) && IS_CASEFOLDED(dir))) - ext4fs_dirhash(dir, fname_name(fname), fname_len(fname), hinfo); + !(IS_ENCRYPTED(dir) && IS_CASEFOLDED(dir))) { + int ret = ext4fs_dirhash(dir, fname_name(fname), + fname_len(fname), hinfo); + if (ret < 0) { + ret_err = ERR_PTR(ret); + goto fail; + } + } hash = hinfo->hash;
if (root->info.unused_flags & 1) { @@ -1111,7 +1119,12 @@ static int htree_dirblock_to_tree(struct hinfo->minor_hash = 0; } } else { - ext4fs_dirhash(dir, de->name, de->name_len, hinfo); + err = ext4fs_dirhash(dir, de->name, + de->name_len, hinfo); + if (err < 0) { + count = err; + goto errout; + } } if ((hinfo->hash < start_hash) || ((hinfo->hash == start_hash) && @@ -1313,8 +1326,12 @@ static int dx_make_map(struct inode *dir if (de->name_len && de->inode) { if (ext4_hash_in_dirent(dir)) h.hash = EXT4_DIRENT_HASH(de); - else - ext4fs_dirhash(dir, de->name, de->name_len, &h); + else { + int err = ext4fs_dirhash(dir, de->name, + de->name_len, &h); + if (err < 0) + return err; + } map_tail--; map_tail->hash = h.hash; map_tail->offs = ((char *) de - base)>>2; @@ -1452,10 +1469,9 @@ int ext4_fname_setup_ci_filename(struct hinfo->hash_version = DX_HASH_SIPHASH; hinfo->seed = NULL; if (cf_name->name) - ext4fs_dirhash(dir, cf_name->name, cf_name->len, hinfo); + return ext4fs_dirhash(dir, cf_name->name, cf_name->len, hinfo); else - ext4fs_dirhash(dir, iname->name, iname->len, hinfo); - return 0; + return ext4fs_dirhash(dir, iname->name, iname->len, hinfo); } #endif
@@ -2298,10 +2314,15 @@ static int make_indexed_dir(handle_t *ha fname->hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
/* casefolded encrypted hashes are computed on fname setup */ - if (!ext4_hash_in_dirent(dir)) - ext4fs_dirhash(dir, fname_name(fname), - fname_len(fname), &fname->hinfo); - + if (!ext4_hash_in_dirent(dir)) { + int err = ext4fs_dirhash(dir, fname_name(fname), + fname_len(fname), &fname->hinfo); + if (err < 0) { + brelse(bh2); + brelse(bh); + return err; + } + } memset(frames, 0, sizeof(frames)); frame = frames; frame->entries = entries;