[PATCH 4.19 260/271] eCryptfs: fix a couple type promotion bugs

[Greg Kroah-Hartman]

From: Dan Carpenter <dan.carpen...@oracle.com>

commit 0bdf8a8245fdea6f075a5fede833a5fcf1b3466c upstream.

ECRYPTFS_SIZE_AND_MARKER_BYTES is type size_t, so if "rc" is negative
that gets type promoted to a high positive value and treated as success.

Fixes: 778aeb42a708 ("eCryptfs: Cleanup and optimize 
ecryptfs_lookup_interpose()")
Signed-off-by: Dan Carpenter <dan.carpen...@oracle.com>
[tyhicks: Use "if/else if" rather than "if/if"]
Cc: sta...@vger.kernel.org
Signed-off-by: Tyler Hicks <tyhi...@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 fs/ecryptfs/crypto.c |   12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -1018,8 +1018,10 @@ int ecryptfs_read_and_validate_header_re
 
        rc = ecryptfs_read_lower(file_size, 0, ECRYPTFS_SIZE_AND_MARKER_BYTES,
                                 inode);
-       if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
-               return rc >= 0 ? -EINVAL : rc;
+       if (rc < 0)
+               return rc;
+       else if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
+               return -EINVAL;
        rc = ecryptfs_validate_marker(marker);
        if (!rc)
                ecryptfs_i_size_init(file_size, inode);
@@ -1381,8 +1383,10 @@ int ecryptfs_read_and_validate_xattr_reg
                                     ecryptfs_inode_to_lower(inode),
                                     ECRYPTFS_XATTR_NAME, file_size,
                                     ECRYPTFS_SIZE_AND_MARKER_BYTES);
-       if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
-               return rc >= 0 ? -EINVAL : rc;
+       if (rc < 0)
+               return rc;
+       else if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
+               return -EINVAL;
        rc = ecryptfs_validate_marker(marker);
        if (!rc)
                ecryptfs_i_size_init(file_size, inode);