resolve: allow IP address within [] brackets

... so that IPv6 addresses can be passed like they can for connect-to
and how they're used in URLs.

Added test 1324 to verify
Reported-by: Alex Malinovich

Fixes #2087
Closes #2091

1 files changed, 12 insertions, 1 deletions

diff --git a/lib/hostip.c b/lib/hostip.c
index abe98028c..7f010a037 100644
--- a/lib/hostip.c
+++ b/lib/hostip.c
@@ -778,7 +778,6 @@ CURLcode Curl_loadhostpairs(struct Curl_easy *data)
 {
   struct curl_slist *hostp;
   char hostname[256];
-  char address[256];
   int port;
 
   for(hostp = data->change.resolve; hostp; hostp = hostp->next) {
@@ -820,6 +819,8 @@ CURLcode Curl_loadhostpairs(struct Curl_easy *data)
       Curl_addrinfo *addr;
       char *entry_id;
       size_t entry_len;
+      char buffer[256];
+      char *address = &buffer[0];
 
       if(3 != sscanf(hostp->data, "%255[^:]:%d:%255s", hostname, &port,
                      address)) {
@@ -828,6 +829,16 @@ CURLcode Curl_loadhostpairs(struct Curl_easy *data)
         continue;
       }
 
+      /* allow IP(v6) address within [brackets] */
+      if(address[0] == '[') {
+        size_t alen = strlen(address);
+        if(address[alen-1] != ']')
+          /* it needs to also end with ] to be valid */
+          continue;
+        address[alen-1] = 0; /* zero terminate there */
+        address++; /* pass the open bracket */
+      }
+
       addr = Curl_str2addr(address, port);
       if(!addr) {
         infof(data, "Address in '%s' found illegal!\n", hostp->data);