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| author |   Eric Biggers <ebiggers@google.com> | 2020-11-17 23:56:06 -0800 |
|---|---|---|
| committer | Eric Biggers <ebiggers@google.com> | 2020-11-24 15:10:27 -0800 |
| commit | 75d18cd1868c2aee43553723872c35d7908f240f (patch) | |
| tree | 6817447dd15423bc064e02106e4f070cace7b053 /fs/ext4/namei.c | |
| parent | fscrypt: add fscrypt_is_nokey_name() (diff) | |
| download | linux-dev-75d18cd1868c2aee43553723872c35d7908f240f.tar.xz linux-dev-75d18cd1868c2aee43553723872c35d7908f240f.zip | |
ext4: prevent creating duplicate encrypted filenames
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>
Diffstat (limited to 'fs/ext4/namei.c')
| -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 33509266f5a0..793fc7db9d28 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -2195,6 +2195,9 @@ 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 (sb_has_strict_encoding(sb) && IS_CASEFOLDED(dir) && sb->s_encoding && utf8_validate(sb->s_encoding, &dentry->d_name)) |