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From:   Aditya Pakki <pakki001@umn.edu>
To:     pakki001@umn.edu
Cc:     kjlu@umn.edu, Tyler Hicks <tyhicks@canonical.com>,
        Andrew Morton <akpm@osdl.org>,
        Michael Halcrow <mhalcrow@us.ibm.com>,
        Adrian Bunk <bunk@stusta.de>,
        Randy Dunlap <rdunlap@infradead.org>,
        "Theodore Ts'o" <tytso@mit.edu>, ecryptfs@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH v2] ecryptfs: replace BUG_ON with error handling code
Date:   Fri, 14 Feb 2020 12:21:01 -0600
Message-Id: <20200214182101.17165-1-pakki001@umn.edu>
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Sender: linux-kernel-owner@vger.kernel.org
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In crypt_scatterlist, if the crypt_stat argument is not set up
correctly, the kernel crashes. Instead, by returning an error code
upstream, the error is handled safely.

The issue is detected via a static analysis tool written by us.

Fixes: 237fead619984 (ecryptfs: fs/Makefile and fs/Kconfig)
Signed-off-by: Aditya Pakki <pakki001@umn.edu>
---
v1: Add missing fixes tag suggested by Markus and Tyler.
---
 fs/ecryptfs/crypto.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index db1ef144c63a..2c449aed1b92 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -311,8 +311,10 @@ static int crypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
 	struct extent_crypt_result ecr;
 	int rc = 0;
 
-	BUG_ON(!crypt_stat || !crypt_stat->tfm
-	       || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED));
+	if (!crypt_stat || !crypt_stat->tfm
+	       || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
+		return -EINVAL;
+
 	if (unlikely(ecryptfs_verbosity > 0)) {
 		ecryptfs_printk(KERN_DEBUG, "Key size [%zd]; key:\n",
 				crypt_stat->key_size);
-- 
2.20.1