f2fs crypto: fix corrupted symlink in encrypted case

In the encrypted symlink case, we should check its corrupted symname after
decrypting it.
Otherwise, we can report -ENOENT incorrectly, if encrypted symname starts with
'\0'.

Cc: stable 4.5+ <stable@vger.kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index 7876f10521019509bbae2888addea516e8cc1db2..6214d9ec89f2cd76f11cb9225400b9afc05d1f6d 100644 (file)
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -1027,12 +1027,6 @@ static const char *f2fs_encrypted_get_link(struct dentry *dentry,
                goto errout;
        }
 
-       /* this is broken symlink case */
-       if (unlikely(cstr.name[0] == 0)) {
-               res = -ENOENT;
-               goto errout;
-       }
-
        if ((cstr.len + sizeof(struct fscrypt_symlink_data) - 1) > max_size) {
                /* Symlink data on the disk is corrupted */
                res = -EIO;
@@ -1046,6 +1040,12 @@ static const char *f2fs_encrypted_get_link(struct dentry *dentry,
        if (res < 0)
                goto errout;
 
+       /* this is broken symlink case */
+       if (unlikely(pstr.name[0] == 0)) {
+               res = -ENOENT;
+               goto errout;
+       }
+
        paddr = pstr.name;
 
        /* Null-terminate the name */