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authorEric Biggers <ebiggers@google.com>2020-11-18 10:56:08 +0300
committerEric Biggers <ebiggers@google.com>2020-11-25 02:10:27 +0300
commit76786a0f083473de31678bdb259a3d4167cf756d (patch)
tree145142f1becfd8ab01443e49d4aac6bec1f5f9c9 /fs/ubifs
parentbfc2b7e8518999003a61f91c1deb5e88ed77b07d (diff)
downloadlinux-76786a0f083473de31678bdb259a3d4167cf756d.tar.xz
ubifs: 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 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@vger.kernel.org Link: https://lore.kernel.org/r/20201118075609.120337-5-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com>
Diffstat (limited to 'fs/ubifs')
-rw-r--r--fs/ubifs/dir.c17
1 files changed, 13 insertions, 4 deletions
diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index 155521e51ac5..08fde777c324 100644
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -270,6 +270,15 @@ 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)
{
@@ -293,7 +302,7 @@ static int ubifs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
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;
@@ -953,7 +962,7 @@ static int ubifs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
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;
@@ -1038,7 +1047,7 @@ static int ubifs_mknod(struct inode *dir, struct dentry *dentry,
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;
@@ -1122,7 +1131,7 @@ static int ubifs_symlink(struct inode *dir, struct dentry *dentry,
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;