inet_net_pton_ipv6: avoid signed vs unsigned comparison

Use a temporary variable to store the number of bytes to be copied
(size_t) and also use it as the memcpy(3) length.  Previously we
copied "size" bytes instead of just the necessary number.
OK claudio@ tb@

diff --git a/lib/libc/net/inet_net_pton.c b/lib/libc/net/inet_net_pton.c
index aaffc18..6100366 100644 (file)
--- a/lib/libc/net/inet_net_pton.c
+++ b/lib/libc/net/inet_net_pton.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: inet_net_pton.c,v 1.11 2021/01/19 16:43:44 florian Exp $      */
+/*     $OpenBSD: inet_net_pton.c,v 1.12 2022/04/13 16:20:11 millert Exp $      */
 
 /*
  * Copyright (c) 2012 by Gilles Chehade <gilles@openbsd.org>
@@ -208,6 +208,7 @@ inet_net_pton_ipv6(const char *src, u_char *dst, size_t size)
        struct in6_addr  in6;
        int              ret;
        int              bits;
+       size_t           bytes
        char             buf[INET6_ADDRSTRLEN + sizeof("/128")];
        char            *sep;
        const char      *errstr;
@@ -235,10 +236,11 @@ inet_net_pton_ipv6(const char *src, u_char *dst, size_t size)
                }
        }
 
-       if ((bits + 7) / 8 > size) {
+       bytes = (bits + 7) / 8;
+       if (bytes > size) {
                errno = EMSGSIZE;
                return (-1);
        }
-       memcpy(dst, &in6.s6_addr, size);
+       memcpy(dst, &in6.s6_addr, bytes);
        return (bits);
 }