fscrypt: don't set policy for a dead directory

commit 5858bdad4d0d0fc18bf29f34c3ac836e0b59441f upstream.

The directory may have been removed when entering
fscrypt_ioctl_set_policy().  If so, the empty_dir() check will return
error for ext4 file system.

ext4_rmdir() sets i_size = 0, then ext4_empty_dir() reports an error
because 'inode->i_size < EXT4_DIR_REC_LEN(1) + EXT4_DIR_REC_LEN(2)'.  If
the fs is mounted with errors=panic, it will trigger a panic issue.

Add the check IS_DEADDIR() to fix this problem.

Fixes: 9bd8212f981e ("ext4 crypto: add encryption policy and password salt support")
Cc: <stable@vger.kernel.org> # v4.1+
Signed-off-by: Hongjie Fang <hongjiefang@asrmicro.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c
index c160d2d..57a97b3 100644 (file)
--- a/fs/crypto/policy.c
+++ b/fs/crypto/policy.c
@@ -114,6 +114,8 @@ int fscrypt_process_policy(struct file *filp,
        if (!inode_has_encryption_context(inode)) {
                if (!S_ISDIR(inode->i_mode))
                        ret = -ENOTDIR;
+               else if (IS_DEADDIR(inode))
+                       ret = -ENOENT;
                else if (!inode->i_sb->s_cop->empty_dir)
                        ret = -EOPNOTSUPP;
                else if (!inode->i_sb->s_cop->empty_dir(inode))