From 5cf8b332429a1dd9afef3337bae92aeddaeff993 Mon Sep 17 00:00:00 2001
From: Valery Ushakov <uwe@stderr.spb.ru>
Date: Wed, 24 Jan 2024 22:24:41 +0300
Subject: [PATCH] awk.c: fix CVE-2023-42366 (bug #15874)

Make sure we don't read past the end of the string in next_token()
when backslash is the last character in an (invalid) regexp.

https://bugs.busybox.net/show_bug.cgi?id=15874
---
 editors/awk.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/editors/awk.c b/editors/awk.c
index 728ee8685..be48df7c7 100644
--- a/editors/awk.c
+++ b/editors/awk.c
@@ -1165,9 +1165,11 @@ static uint32_t next_token(uint32_t expected)
 					s[-1] = bb_process_escape_sequence((const char **)&pp);
 					if (*p == '\\')
 						*s++ = '\\';
-					if (pp == p)
+					if (pp == p) {
+						if (*p == '\0')
+							syntax_error(EMSG_UNEXP_EOS);
 						*s++ = *p++;
-					else
+					} else
 						p = pp;
 				}
 			}
-- 
2.34.1

