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| author | Lukas Czerner <lczerner@redhat.com> | 2022-07-04 16:27:21 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-08-17 15:16:17 +0200 |
| commit | 9d96996de0d2bc53f617086864b3b990089d9d8b (patch) | |
| tree | 858c8a767ce7f71de6a74f26fcfb15fbf62b1cc4 | |
| parent | 193fc6f0de44a884fd4db82a9a368dafcd2c9bed (diff) | |
| download | linux-stable-9d96996de0d2bc53f617086864b3b990089d9d8b.tar.gz linux-stable-9d96996de0d2bc53f617086864b3b990089d9d8b.tar.bz2 linux-stable-9d96996de0d2bc53f617086864b3b990089d9d8b.zip | |
ext4: make sure ext4_append() always allocates new block
[ Upstream commit b8a04fe77ef1360fbf73c80fddbdfeaa9407ed1b ]
ext4_append() must always allocate a new block, otherwise we run the
risk of overwriting existing directory block corrupting the directory
tree in the process resulting in all manner of problems later on.
Add a sanity check to see if the logical block is already allocated and
error out if it is.
Cc: stable@kernel.org
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Link: https://lore.kernel.org/r/20220704142721.157985-2-lczerner@redhat.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | fs/ext4/namei.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index cf460aa4f81d..4af441494e09 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -54,6 +54,7 @@ static struct buffer_head *ext4_append(handle_t *handle, struct inode *inode, ext4_lblk_t *block) { + struct ext4_map_blocks map; struct buffer_head *bh; int err; @@ -63,6 +64,21 @@ static struct buffer_head *ext4_append(handle_t *handle, return ERR_PTR(-ENOSPC); *block = inode->i_size >> inode->i_sb->s_blocksize_bits; + map.m_lblk = *block; + map.m_len = 1; + + /* + * We're appending new directory block. Make sure the block is not + * allocated yet, otherwise we will end up corrupting the + * directory. + */ + err = ext4_map_blocks(NULL, inode, &map, 0); + if (err < 0) + return ERR_PTR(err); + if (err) { + EXT4_ERROR_INODE(inode, "Logical block already allocated"); + return ERR_PTR(-EFSCORRUPTED); + } bh = ext4_bread(handle, inode, *block, EXT4_GET_BLOCKS_CREATE); if (IS_ERR(bh)) |