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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Aditya Pakki <pakki001@umn.edu>,
        Tyler Hicks <code@tyhicks.com>
Subject: [PATCH 4.4 109/113] ecryptfs: replace BUG_ON with error handling code
Date:   Thu, 27 Feb 2020 14:37:05 +0100
Message-Id: <20200227132229.244579940@linuxfoundation.org>
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From: Aditya Pakki <pakki001@umn.edu>

commit 2c2a7552dd6465e8fde6bc9cccf8d66ed1c1eb72 upstream.

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>
Signed-off-by: Tyler Hicks <code@tyhicks.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/ecryptfs/crypto.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -346,8 +346,10 @@ static int crypt_scatterlist(struct ecry
 	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);