fix IPv6 addresses table lookups

Rework parse_sockaddr() to not reach inet_pton() with a brace-wrapped
IPv6 address.

Issue reported by Kirill Miazine.
ok millert@

diff --git a/usr.sbin/smtpd/table.c b/usr.sbin/smtpd/table.c
index 7328cf5..99db7b0 100644 (file)
--- a/usr.sbin/smtpd/table.c
+++ b/usr.sbin/smtpd/table.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: table.c,v 1.50 2021/06/14 17:58:16 eric Exp $ */
+/*     $OpenBSD: table.c,v 1.51 2024/01/04 09:34:03 op Exp $   */
 
 /*
  * Copyright (c) 2013 Eric Faurot <eric@openbsd.org>
@@ -628,7 +628,8 @@ parse_sockaddr(struct sockaddr *sa, int family, const char *str)
        struct in6_addr          in6a;
        struct sockaddr_in      *sin;
        struct sockaddr_in6     *sin6;
-       char                    *cp, *str2;
+       char                    *cp;
+       char                     addr[NI_MAXHOST];
        const char              *errstr;
 
        switch (family) {
@@ -649,21 +650,19 @@ parse_sockaddr(struct sockaddr *sa, int family, const char *str)
                return (0);
 
        case PF_INET6:
-               if (strncasecmp("ipv6:", str, 5) == 0)
+               if (*str == '[')
+                       str++;
+               if (!strncasecmp("ipv6:", str, 5))
                        str += 5;
-               cp = strchr(str, SCOPE_DELIMITER);
-               if (cp) {
-                       str2 = strdup(str);
-                       if (str2 == NULL)
-                               return (-1);
-                       str2[cp - str] = '\0';
-                       if (inet_pton(PF_INET6, str2, &in6a) != 1) {
-                               free(str2);
-                               return (-1);
-                       }
-                       cp++;
-                       free(str2);
-               } else if (inet_pton(PF_INET6, str, &in6a) != 1)
+
+               if (strlcpy(addr, str, sizeof(addr)) >= sizeof(addr))
+                       return (-1);
+               if ((cp = strchr(addr, ']')) != NULL)
+                       *cp = '\0';
+               if ((cp = strchr(addr, SCOPE_DELIMITER)) != NULL)
+                       *cp++ = '\0';
+
+               if (inet_pton(PF_INET6, addr, &in6a) != 1)
                        return (-1);
 
                sin6 = (struct sockaddr_in6 *)sa;