diff options
author | Luís Henriques <lhenriques@suse.de> | 2022-10-12 16:13:30 +0300 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-11-10 20:14:28 +0300 |
commit | 156451a67b93986fb07c274ef6995ff40766c5ad (patch) | |
tree | 3a69d06ebcfa60c2bda680de6ee26ccddc80c823 /fs/ext4 | |
parent | 5370b965b7a945bb8f48b9ee23d83a76a947902e (diff) | |
download | linux-156451a67b93986fb07c274ef6995ff40766c5ad.tar.xz |
ext4: fix BUG_ON() when directory entry has invalid rec_len
commit 17a0bc9bd697f75cfdf9b378d5eb2d7409c91340 upstream.
The rec_len field in the directory entry has to be a multiple of 4. A
corrupted filesystem image can be used to hit a BUG() in
ext4_rec_len_to_disk(), called from make_indexed_dir().
------------[ cut here ]------------
kernel BUG at fs/ext4/ext4.h:2413!
...
RIP: 0010:make_indexed_dir+0x53f/0x5f0
...
Call Trace:
<TASK>
? add_dirent_to_buf+0x1b2/0x200
ext4_add_entry+0x36e/0x480
ext4_add_nondir+0x2b/0xc0
ext4_create+0x163/0x200
path_openat+0x635/0xe90
do_filp_open+0xb4/0x160
? __create_object.isra.0+0x1de/0x3b0
? _raw_spin_unlock+0x12/0x30
do_sys_openat2+0x91/0x150
__x64_sys_open+0x6c/0xa0
do_syscall_64+0x3c/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
The fix simply adds a call to ext4_check_dir_entry() to validate the
directory entry, returning -EFSCORRUPTED if the entry is invalid.
CC: stable@kernel.org
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216540
Signed-off-by: Luís Henriques <lhenriques@suse.de>
Link: https://lore.kernel.org/r/20221012131330.32456-1-lhenriques@suse.de
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/ext4')
-rw-r--r-- | fs/ext4/namei.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index 646cc1935dff..b2e131d11cf8 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -2153,8 +2153,16 @@ static int make_indexed_dir(handle_t *handle, struct ext4_filename *fname, memcpy(data2, de, len); de = (struct ext4_dir_entry_2 *) data2; top = data2 + len; - while ((char *)(de2 = ext4_next_entry(de, blocksize)) < top) + while ((char *)(de2 = ext4_next_entry(de, blocksize)) < top) { + if (ext4_check_dir_entry(dir, NULL, de, bh2, data2, len, + (data2 + (blocksize - csum_size) - + (char *) de))) { + brelse(bh2); + brelse(bh); + return -EFSCORRUPTED; + } de = de2; + } de->rec_len = ext4_rec_len_to_disk(data2 + (blocksize - csum_size) - (char *) de, blocksize); |