whois: use getline(3) instead of fgetln(3)

This simplifies the code and fixes a potential out of bounds read.
OK op@ mbuhl@

diff --git a/usr.bin/whois/whois.c b/usr.bin/whois/whois.c
index b554f0d..ef0d37c 100644 (file)
--- a/usr.bin/whois/whois.c
+++ b/usr.bin/whois/whois.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: whois.c,v 1.62 2024/03/24 19:51:47 millert Exp $   */
+/*      $OpenBSD: whois.c,v 1.63 2024/03/25 15:52:39 millert Exp $   */
 
 /*
  * Copyright (c) 1980, 1993
@@ -166,8 +166,8 @@ int
 whois(const char *query, const char *server, const char *port, int flags)
 {
        FILE *fp;
-       char *buf, *p, *nhost, *nbuf = NULL;
-       size_t len;
+       char *p, *nhost, *buf = NULL;
+       size_t len, bufsize = 0;
        int i, s, error;
        const char *reason = NULL, *fmt;
        struct addrinfo hints, *res, *ai;
@@ -228,24 +228,15 @@ whois(const char *query, const char *server, const char *port, int flags)
        fprintf(fp, fmt, query);
        fflush(fp);
        nhost = NULL;
-       while ((buf = fgetln(fp, &len)) != NULL) {
+       while ((len = getline(&buf, &bufsize, fp)) != (size_t)-1) {
                /* Nominet */
                if (!(flags & WHOIS_SPAM_ME) &&
                    len == 5 && strncmp(buf, "-- \r\n", 5) == 0)
                        break;
 
                p = buf + len - 1;
-               if (isspace((unsigned char)*p)) {
-                       do
-                               *p = '\0';
-                       while (p > buf && isspace((unsigned char)*--p));
-               } else {
-                       if ((nbuf = malloc(len + 1)) == NULL)
-                               err(1, "malloc");
-                       memcpy(nbuf, buf, len);
-                       nbuf[len] = '\0';
-                       buf = nbuf;
-               }
+               while (p > buf && isspace((unsigned char)*p))
+                       *p-- = '\0';
                puts(buf);
 
                if (nhost == NULL && (flags & WHOIS_RECURSE)) {
@@ -254,10 +245,8 @@ whois(const char *query, const char *server, const char *port, int flags)
                                while (isblank((unsigned char)*p))
                                        p++;
                                if ((len = strcspn(p, " \t\n\r"))) {
-                                       if ((nhost = malloc(len + 1)) == NULL)
-                                               err(1, "malloc");
-                                       memcpy(nhost, p, len);
-                                       nhost[len] = '\0';
+                                       if ((nhost = strndup(p, len)) == NULL)
+                                               err(1, "strndup");
                                }
                        } else if (strcmp(server, ANICHOST) == 0) {
                                for (p = buf; *p != '\0'; p++)
@@ -283,7 +272,7 @@ whois(const char *query, const char *server, const char *port, int flags)
                }
        }
        fclose(fp);
-       free(nbuf);
+       free(buf);
 
        if (nhost != NULL) {
                error = whois(query, nhost, port, 0);