linux-kernel - [PATCH 4.9 120/223] eCryptfs: fix a couple type promotion bugs

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Message-Id: <20190802092246.963008457@linuxfoundation.org>
Date:   Fri,  2 Aug 2019 11:35:45 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Dan Carpenter <dan.carpenter@...cle.com>,
        Tyler Hicks <tyhicks@...onical.com>
Subject: [PATCH 4.9 120/223] eCryptfs: fix a couple type promotion bugs

From: Dan Carpenter <dan.carpenter@...cle.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.carpenter@...cle.com>
[tyhicks: Use "if/else if" rather than "if/if"]
Cc: stable@...r.kernel.org
Signed-off-by: Tyler Hicks <tyhicks@...onical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

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

--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -1034,8 +1034,10 @@ 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);
@@ -1397,8 +1399,10 @@ 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);