1 files changed, 124 insertions, 0 deletions
diff --git a/src/lib/krb5/krb/parse_host_string.c b/src/lib/krb5/krb/parse_host_string.c
new file mode 100644
index 0000000000000..2330be6a51996
--- /dev/null
+++ b/src/lib/krb5/krb/parse_host_string.c
@@ -0,0 +1,124 @@
+/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
+/* lib/krb5/krb/parse_host_string.c - Parse host strings into host and port */
+/*
+ * Copyright (C) 2016 by the Massachusetts Institute of Technology.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in
+ *   the documentation and/or other materials provided with the
+ *   distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "k5-int.h"
+#include <ctype.h>
+
+/* Return true if s is composed solely of digits. */
+krb5_boolean
+k5_is_string_numeric(const char *s)
+{
+    if (*s == '\0')
+        return FALSE;
+
+    for (; *s != '\0'; s++) {
+        if (!isdigit(*s))
+            return FALSE;
+    }
+
+    return TRUE;
+}
+
+/*
+ * Parse a string containing a host specifier. The expected format for the
+ * string is:
+ *
+ * host[:port] or port
+ *
+ * host and port are optional, though one must be present.  host may have
+ * brackets around it for IPv6 addresses.
+ *
+ * Arguments:
+ * address - The address string that should be parsed.
+ * default_port - The default port to use if no port is found.
+ * host_out - An output pointer for the parsed host, or NULL if no host was
+ * specified or an error occured.  Must be freed.
+ * port_out - An output pointer for the parsed port.  Will be 0 on error.
+ *
+ * Returns 0 on success, otherwise an error.
+ */
+krb5_error_code
+k5_parse_host_string(const char *address, int default_port, char **host_out,
+                     int *port_out)
+{
+    krb5_error_code ret;
+    int port_num;
+    const char *p, *host = NULL, *port = NULL;
+    char *endptr, *hostname = NULL;
+    size_t hostlen = 0;
+    unsigned long l;
+
+    *host_out = NULL;
+    *port_out = 0;
+
+    if (address == NULL || *address == '\0' || *address == ':')
+        return EINVAL;
+    if (default_port < 0 || default_port > 65535)
+        return EINVAL;
+
+    /* Find the bounds of the host string and the start of the port string. */
+    if (k5_is_string_numeric(address)) {
+        port = address;
+    } else if (*address == '[' && (p = strchr(address, ']')) != NULL) {
+        host = address + 1;
+        hostlen = p - host;
+        if (*(p + 1) == ':')
+            port = p + 2;
+    } else {
+        host = address;
+        hostlen = strcspn(host, " \t:");
+        if (host[hostlen] == ':')
+            port = host + hostlen + 1;
+    }
+
+    /* Parse the port number, or use the default port. */
+    if (port != NULL) {
+        errno = 0;
+        l = strtoul(port, &endptr, 10);
+        if (errno || endptr == port || *endptr != '\0' || l > 65535)
+            return EINVAL;
+        port_num = l;
+    } else {
+        port_num = default_port;
+    }
+
+    /* Copy the host if it was specified. */
+    if (host != NULL) {
+        hostname = k5memdup0(host, hostlen, &ret);
+        if (hostname == NULL)
+            return ENOMEM;
+    }
+
+    *host_out = hostname;
+    *port_out = port_num;
+    return 0;
+}