Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Jan Kara <jack@suse.cz>,
        syzbot+cd311b1e43cc25f90d18@syzkaller.appspotmail.com,
        Sasha Levin <sashal@kernel.org>, jack@suse.com
Subject: [PATCH AUTOSEL 6.4 53/58] udf: Fix uninitialized array access for some pathnames
Date:   Sun, 23 Jul 2023 21:13:21 -0400
Message-Id: <20230724011338.2298062-53-sashal@kernel.org>
In-Reply-To: <20230724011338.2298062-1-sashal@kernel.org>
References: <20230724011338.2298062-1-sashal@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Jan Kara <jack@suse.cz>

[ Upstream commit 028f6055c912588e6f72722d89c30b401bbcf013 ]

For filenames that begin with . and are between 2 and 5 characters long,
UDF charset conversion code would read uninitialized memory in the
output buffer. The only practical impact is that the name may be prepended a
"unification hash" when it is not actually needed but still it is good
to fix this.

Reported-by: syzbot+cd311b1e43cc25f90d18@syzkaller.appspotmail.com
Link: https://lore.kernel.org/all/000000000000e2638a05fe9dc8f9@google.com
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/udf/unicode.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/udf/unicode.c b/fs/udf/unicode.c
index 622569007b530..2142cbd1dde24 100644
--- a/fs/udf/unicode.c
+++ b/fs/udf/unicode.c
@@ -247,7 +247,7 @@ static int udf_name_from_CS0(struct super_block *sb,
 	}
 
 	if (translate) {
-		if (str_o_len <= 2 && str_o[0] == '.' &&
+		if (str_o_len > 0 && str_o_len <= 2 && str_o[0] == '.' &&
 		    (str_o_len == 1 || str_o[1] == '.'))
 			needsCRC = 1;
 		if (needsCRC) {
-- 
2.39.2