From 1023a9ad12d146608ba6326a3114f9b23b812124 Mon Sep 17 00:00:00 2001

From: =?UTF-8?q?Tim=20R=C3=BChsen?= <tim.ruehsen@gmx.de>

Date: Sat, 15 Jan 2022 22:38:32 +0100

Subject: [PATCH] Fix stack buffer overflow WRITE 1 in domain_to_punycode()

Reported-by: oss-fuzz (issue 39424 and issue 39226)

The affected code would only be built into the library when

configured to build without any IDNA library.

---

 src/psl.c | 2 +-

 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/psl.c b/src/psl.c

index 0e04778..7bfc3cb 100644

--- a/src/psl.c

+++ b/src/psl.c

@@ -590,7 +590,7 @@ static int domain_to_punycode(const char *domain, char *out, size_t outsize)

 			memcpy(out + outlen, "xn--", 4);

 			outlen += 4;

-			labellen = outsize - outlen - 1; // -1 to leave space for the trailing \0

+			labellen = outsize - outlen - (e != NULL) - 1; // -1 to leave space for the trailing \0

 			if (punycode_encode(inputlen, input, &labellen, out + outlen))

 				return 1;

 			outlen += labellen;

-- 

2.33.5