diff options
| author | Eric Biggers <ebiggers@google.com> | 2020-12-28 10:54:31 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-01-06 14:48:35 +0100 |
| commit | 3ebfed353afd3a7b2ccd4c858691fe35db50ba0f (patch) | |
| tree | a8a1724579ca5ba4f6fa28615e758ac56a4137eb /fs | |
| parent | faa72d97c3e3cddb9382aab3a7042deb5601a9d0 (diff) | |
ext4: prevent creating duplicate encrypted filenames
commit 75d18cd1868c2aee43553723872c35d7908f240f upstream.
As described in "fscrypt: add fscrypt_is_nokey_name()", it's possible to
create a duplicate filename in an encrypted directory by creating a file
concurrently with adding the directory's encryption key.
Fix this bug on ext4 by rejecting no-key dentries in ext4_add_entry().
Note that the duplicate check in ext4_find_dest_de() sometimes prevented
this bug. However in many cases it didn't, since ext4_find_dest_de()
doesn't examine every dentry.
Fixes: 4461471107b7 ("ext4 crypto: enable filename encryption")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20201118075609.120337-3-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/ext4/namei.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index 36a81b57012a..59038e361337 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -2192,6 +2192,9 @@ static int ext4_add_entry(handle_t *handle, struct dentry *dentry, if (!dentry->d_name.len) return -EINVAL; + if (fscrypt_is_nokey_name(dentry)) + return -ENOKEY; + #ifdef CONFIG_UNICODE if (ext4_has_strict_mode(sbi) && IS_CASEFOLDED(dir) && sbi->s_encoding && utf8_validate(sbi->s_encoding, &dentry->d_name)) |