Fix/check curl sticky redir (#2188)

* check_curl: avoid freeing memory when we don't know where it came from

* check_curl: when using -f sticky conserve IPv6 addresses properly

When running the check on an ipv6 address with a sticky onredirect
policy like in this example:

  check_curl -6 -H example.com -I ::1 -f sticky

It results in a getaddrinfo error:

  HTTP CRITICAL - Unable to lookup IP address for '[::1]': getaddrinfo returned -3 - Temporary failure in name resolution

This happens because in check_http() if the content of server_addr is an
ipv6 address enclosing brackets are added and on redirection a
subsequent call to check_http() will pass this now bracketed value to
getaddrinfo resulting in the error.

To work around this, strip the brackets from the address prior to the
lookup_host() call.

* add Michael Jeanson to thanks

1 files changed, 3 insertions, 7 deletions

diff --git a/plugins/check_curl.c b/plugins/check_curl.c
index ba856a11..e3e514ff 100644
--- a/plugins/check_curl.c
+++ b/plugins/check_curl.c
@@ -69,10 +69,6 @@ const char *email = "devel@monitoring-plugins.org";
 #include <netdb.h>
 
 enum {
-        MAX_IPV4_HOSTLENGTH = 255,
-};
-
-enum {
         REGS = 2,
 };
 
@@ -789,21 +785,21 @@ redir_wrapper redir(curlhelp_write_curlbuf *header_buf, const check_curl_config
         /* set new values for redirected request */
 
         if (!(config.followsticky & STICKY_HOST)) {
-                free(working_state.server_address);
+                // free(working_state.server_address);
                 working_state.server_address = strndup(new_host, MAX_IPV4_HOSTLENGTH);
         }
         if (!(config.followsticky & STICKY_PORT)) {
                 working_state.serverPort = (unsigned short)new_port;
         }
 
-        free(working_state.host_name);
+        // free(working_state.host_name);
         working_state.host_name = strndup(new_host, MAX_IPV4_HOSTLENGTH);
 
         /* reset virtual port */
         working_state.virtualPort = working_state.serverPort;
 
         free(new_host);
-        free(working_state.server_url);
+        // free(working_state.server_url);
         working_state.server_url = new_url;
 
         uriFreeUriMembersA(&uri);