From 04fb28bc511cf14807810d0563c7f07e00829edd Mon Sep 17 00:00:00 2001
From: Michael Halcrow <mhalcrow@google.com>
Date: Wed, 26 Nov 2014 09:09:16 -0800
Subject: [PATCH] eCryptfs: Remove buggy and unnecessary write in file name
 decode routine

commit 942080643bce061c3dd9d5718d3b745dcb39a8bc upstream.

Dmitry Chernenkov used KASAN to discover that eCryptfs writes past the
end of the allocated buffer during encrypted filename decoding. This
fix corrects the issue by getting rid of the unnecessary 0 write when
the current bit offset is 2.

Signed-off-by: Michael Halcrow <mhalcrow@google.com>
Reported-by: Dmitry Chernenkov <dmitryc@google.com>
Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Signed-off-by: Zefan Li <lizefan@huawei.com>
---
 fs/ecryptfs/crypto.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index ea9931281557a..3d0633891f286 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -2044,7 +2044,6 @@ ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size,
 			break;
 		case 2:
 			dst[dst_byte_offset++] |= (src_byte);
-			dst[dst_byte_offset] = 0;
 			current_bit_offset = 0;
 			break;
 		}
-- 
2.47.2