From f2d130454e46c3989af1b4f882b6a666d24fa2e0 Mon Sep 17 00:00:00 2001
From: Michael Halcrow <mhalcrow@google.com>
Date: Wed, 26 Nov 2014 09:09:16 -0800
Subject: 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: Ben Hutchings <ben@decadent.org.uk>
---
 fs/ecryptfs/crypto.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index 68b19ab..dceedec 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -2038,7 +2038,6 @@ 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;
 		}
-- 
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