From: Eric Biggers ebiggers@google.com
commit bfc2b7e8518999003a61f91c1deb5e88ed77b07d 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 f2fs by rejecting no-key dentries in f2fs_add_link().
Note that the weird check for the current task in f2fs_do_add_link() seems to make this bug difficult to reproduce on f2fs.
Fixes: 9ea97163c6da ("f2fs crypto: add filename encryption for f2fs_add_link") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20201118075609.120337-4-ebiggers@kernel.org Signed-off-by: Eric Biggers ebiggers@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/f2fs/f2fs.h | 2 ++ 1 file changed, 2 insertions(+)
--- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -2998,6 +2998,8 @@ bool f2fs_empty_dir(struct inode *dir);
static inline int f2fs_add_link(struct dentry *dentry, struct inode *inode) { + if (fscrypt_is_nokey_name(dentry)) + return -ENOKEY; return f2fs_do_add_link(d_inode(dentry->d_parent), &dentry->d_name, inode, inode->i_ino, inode->i_mode); }