libunbound has const correctness issues...

src/common/dns_utils.cpp

@@ -27,6 +27,7 @@
 // THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include "common/dns_utils.h"
+#include <cstring>
 #include <sstream>
 #include <ldns/rr.h> // for RR type and class defs
 #include <unbound.h>
@@ -99,9 +100,11 @@ DNSResolver::DNSResolver() : m_data(new DNSResolverData())
   // init libunbound context
   m_data->m_ub_context = ub_ctx_create();
 
+  char empty_string = '\0';
+
   // look for "/etc/resolv.conf" and "/etc/hosts" or platform equivalent
-  ub_ctx_resolvconf(m_data->m_ub_context, "");
-  ub_ctx_hosts(m_data->m_ub_context, "");
+  ub_ctx_resolvconf(m_data->m_ub_context, &empty_string);
+  ub_ctx_hosts(m_data->m_ub_context, &empty_string);
 }
 
 DNSResolver::~DNSResolver()
@@ -119,7 +122,10 @@ DNSResolver::~DNSResolver()
 std::vector<std::string> DNSResolver::get_ipv4(const std::string& url)
 {
   std::vector<std::string> addresses;
+  char urlC[1000];  // waaaay too big, but just in case...
 
+  strncpy(urlC, url.c_str(), 999);
+  urlC[999] = '\0';
   if (!check_address_syntax(url))
   {
     return addresses;
@@ -129,7 +135,7 @@ std::vector<std::string> DNSResolver::get_ipv4(const std::string& url)
   ub_result_ptr result;
 
   // call DNS resolver, blocking.  if return value not zero, something went wrong
-  if (!ub_resolve(m_data->m_ub_context, url.c_str(), LDNS_RR_TYPE_A, LDNS_RR_CLASS_IN, &(result.ptr)))
+  if (!ub_resolve(m_data->m_ub_context, urlC, LDNS_RR_TYPE_A, LDNS_RR_CLASS_IN, &(result.ptr)))
   {
     if (result.ptr->havedata)
     {
@@ -146,6 +152,10 @@ std::vector<std::string> DNSResolver::get_ipv4(const std::string& url)
 std::vector<std::string> DNSResolver::get_ipv6(const std::string& url)
 {
   std::vector<std::string> addresses;
+  char urlC[1000];  // waaaay too big, but just in case...
+
+  strncpy(urlC, url.c_str(), 999);
+  urlC[999] = '\0';
 
   if (!check_address_syntax(url))
   {
@@ -155,7 +165,7 @@ std::vector<std::string> DNSResolver::get_ipv6(const std::string& url)
   ub_result_ptr result;
 
   // call DNS resolver, blocking.  if return value not zero, something went wrong
-  if (!ub_resolve(m_data->m_ub_context, url.c_str(), LDNS_RR_TYPE_AAAA, LDNS_RR_CLASS_IN, &(result.ptr)))
+  if (!ub_resolve(m_data->m_ub_context, urlC, LDNS_RR_TYPE_AAAA, LDNS_RR_CLASS_IN, &(result.ptr)))
   {
     if (result.ptr->havedata)
     {
@@ -172,6 +182,10 @@ std::vector<std::string> DNSResolver::get_ipv6(const std::string& url)
 std::vector<std::string> DNSResolver::get_txt_record(const std::string& url)
 {
   std::vector<std::string> records;
+  char urlC[1000];  // waaaay too big, but just in case...
+
+  strncpy(urlC, url.c_str(), 999);
+  urlC[999] = '\0';
 
   if (!check_address_syntax(url))
   {
@@ -181,7 +195,7 @@ std::vector<std::string> DNSResolver::get_txt_record(const std::string& url)
   ub_result_ptr result;
 
   // call DNS resolver, blocking.  if return value not zero, something went wrong
-  if (!ub_resolve(m_data->m_ub_context, url.c_str(), LDNS_RR_TYPE_TXT, LDNS_RR_CLASS_IN, &(result.ptr)))
+  if (!ub_resolve(m_data->m_ub_context, urlC, LDNS_RR_TYPE_TXT, LDNS_RR_CLASS_IN, &(result.ptr)))
   {
     if (result.ptr->havedata)
     {