[PATCH v2] unicode: don't write -1 after NUL terminator

From: Jason A. Donenfeld
Date: Thu Nov 03 2022 - 07:30:46 EST


If the intention is to overwrite the first NUL with a -1, s[strlen(s)]
is the first NUL, not s[strlen(s)+1].

Cc: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx>
---
fs/unicode/mkutf8data.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/unicode/mkutf8data.c b/fs/unicode/mkutf8data.c
index bc1a7c8b5c8d..61800e0d3226 100644
--- a/fs/unicode/mkutf8data.c
+++ b/fs/unicode/mkutf8data.c
@@ -3194,7 +3194,7 @@ static int normalize_line(struct tree *tree)
/* Second test: length-limited string. */
s = buf2;
/* Replace NUL with a value that will cause an error if seen. */
- s[strlen(s) + 1] = -1;
+ s[strlen(s)] = -1;
t = buf3;
if (utf8cursor(&u8c, tree, s))
return -1;
--
2.38.1