From: Eric Biggers <ebiggers@xxxxxxxxxx>
commit 76786a0f083473de31678bdb259a3d4167cf756d 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 ubifs by rejecting no-key dentries in ubifs_create(),
ubifs_mkdir(), ubifs_mknod(), and ubifs_symlink().
Note that ubifs doesn't actually report the duplicate filenames from
readdir, but rather it seems to replace the original dentry with a new
one (which is still wrong, just a different effect from ext4).
On ubifs, this fixes xfstest generic/595 as well as the new xfstest I
wrote specifically for this bug.
Fixes: f4f61d2cc6d8 ("ubifs: Implement encrypted filenames")
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/20201118075609.120337-5-ebiggers@xxxxxxxxxx
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/ubifs/dir.c | 17 +++++++++++++----
1 file changed, 13 insertions(+), 4 deletions(-)
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -278,6 +278,15 @@ done:
return d_splice_alias(inode, dentry);
}
+static int ubifs_prepare_create(struct inode *dir, struct dentry *dentry,
+ struct fscrypt_name *nm)
+{
+ if (fscrypt_is_nokey_name(dentry))
+ return -ENOKEY;
+
+ return fscrypt_setup_filename(dir, &dentry->d_name, 0, nm);
+}
+
static int ubifs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
bool excl)
{
@@ -301,7 +310,7 @@ static int ubifs_create(struct inode *di
if (err)
return err;
- err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm);
+ err = ubifs_prepare_create(dir, dentry, &nm);
if (err)
goto out_budg;
@@ -961,7 +970,7 @@ static int ubifs_mkdir(struct inode *dir
if (err)
return err;
- err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm);
+ err = ubifs_prepare_create(dir, dentry, &nm);
if (err)
goto out_budg;
@@ -1046,7 +1055,7 @@ static int ubifs_mknod(struct inode *dir
return err;
}
- err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm);
+ err = ubifs_prepare_create(dir, dentry, &nm);
if (err) {
kfree(dev);
goto out_budg;
@@ -1130,7 +1139,7 @@ static int ubifs_symlink(struct inode *d
if (err)
return err;
- err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm);
+ err = ubifs_prepare_create(dir, dentry, &nm);
if (err)
goto out_budg;
