Add tls_client_issuer_name log variable and expose it to mruby

doc/nghttpx.h2r

@@ -376,6 +376,10 @@ respectively.
 
         Return the SHA-1 fingerprint of a client certificate.
 
+    .. rb:attr_reader:: tls_client_issuer_name
+
+        Return the issuer name of a client certificate.
+
     .. rb:attr_reader:: tls_client_subject_name
 
         Return the subject name of a client certificate.

gennghttpxfun.py

@@ -194,6 +194,7 @@ LOGVARS = [
     "tls_client_fingerprint_sha256",
     "tls_client_fingerprint_sha1",
     "tls_client_subject_name",
+    "tls_client_issuer_name",
     "backend_host",
     "backend_port",
 ]

src/shrpx.cc

@@ -2500,6 +2500,8 @@ Logging:
                 client certificate.
               * $tls_client_subject_name:   subject  name   in  client
                 certificate.
+              * $tls_client_issuer_name:   issuer   name   in   client
+                certificate.
               * $tls_protocol: protocol for SSL/TLS connection.
               * $tls_session_id: session ID for SSL/TLS connection.
               * $tls_session_reused:  "r"   if  SSL/TLS   session  was

src/shrpx_config.cc

@@ -510,6 +510,15 @@ LogFragmentType log_var_lookup_token(const char *name, size_t namelen) {
       break;
     }
     break;
+  case 22:
+    switch (name[21]) {
+    case 'e':
+      if (util::strieq_l("tls_client_issuer_nam", name, 21)) {
+        return SHRPX_LOGF_TLS_CLIENT_ISSUER_NAME;
+      }
+      break;
+    }
+    break;
   case 23:
     switch (name[22]) {
     case 'e':

src/shrpx_log.cc

@@ -557,6 +557,7 @@ void upstream_accesslog(const std::vector<LogFragment> &lfv,
       std::tie(p, last) = copy_hex_low(buf.data(), len, p, last);
       break;
     }
+    case SHRPX_LOGF_TLS_CLIENT_ISSUER_NAME:
     case SHRPX_LOGF_TLS_CLIENT_SUBJECT_NAME: {
       if (!lgsp.ssl) {
         std::tie(p, last) = copy('-', p, last);
@@ -567,7 +568,9 @@ void upstream_accesslog(const std::vector<LogFragment> &lfv,
         std::tie(p, last) = copy('-', p, last);
         break;
       }
-      auto name = tls::get_x509_subject_name(balloc, x);
+      auto name = lf.type == SHRPX_LOGF_TLS_CLIENT_ISSUER_NAME
+                      ? tls::get_x509_issuer_name(balloc, x)
+                      : tls::get_x509_subject_name(balloc, x);
       X509_free(x);
       if (name.empty()) {
         std::tie(p, last) = copy('-', p, last);

src/shrpx_log.h

@@ -140,6 +140,7 @@ enum LogFragmentType {
   SHRPX_LOGF_TLS_SNI,
   SHRPX_LOGF_TLS_CLIENT_FINGERPRINT_SHA1,
   SHRPX_LOGF_TLS_CLIENT_FINGERPRINT_SHA256,
+  SHRPX_LOGF_TLS_CLIENT_ISSUER_NAME,
   SHRPX_LOGF_TLS_CLIENT_SUBJECT_NAME,
   SHRPX_LOGF_BACKEND_HOST,
   SHRPX_LOGF_BACKEND_PORT,

src/shrpx_mruby_module_env.cc

@@ -211,6 +211,30 @@ mrb_value env_get_tls_client_subject_name(mrb_state *mrb, mrb_value self) {
 }
 } // namespace
 
+namespace {
+mrb_value env_get_tls_client_issuer_name(mrb_state *mrb, mrb_value self) {
+  auto data = static_cast<MRubyAssocData *>(mrb->ud);
+  auto downstream = data->downstream;
+  auto upstream = downstream->get_upstream();
+  auto handler = upstream->get_client_handler();
+  auto ssl = handler->get_ssl();
+
+  if (!ssl) {
+    return mrb_str_new_static(mrb, "", 0);
+  }
+
+  auto x = SSL_get_peer_certificate(ssl);
+  if (!x) {
+    return mrb_str_new_static(mrb, "", 0);
+  }
+
+  auto &balloc = downstream->get_block_allocator();
+  auto name = tls::get_x509_issuer_name(balloc, x);
+  X509_free(x);
+  return mrb_str_new(mrb, name.c_str(), name.size());
+}
+} // namespace
+
 namespace {
 mrb_value env_get_tls_cipher(mrb_state *mrb, mrb_value self) {
   auto data = static_cast<MRubyAssocData *>(mrb->ud);
@@ -320,6 +344,8 @@ void init_env_class(mrb_state *mrb, RClass *module) {
                     env_get_tls_client_fingerprint_sha256, MRB_ARGS_NONE());
   mrb_define_method(mrb, env_class, "tls_client_fingerprint_sha1",
                     env_get_tls_client_fingerprint_sha1, MRB_ARGS_NONE());
+  mrb_define_method(mrb, env_class, "tls_client_issuer_name",
+                    env_get_tls_client_issuer_name, MRB_ARGS_NONE());
   mrb_define_method(mrb, env_class, "tls_client_subject_name",
                     env_get_tls_client_subject_name, MRB_ARGS_NONE());
   mrb_define_method(mrb, env_class, "tls_cipher", env_get_tls_cipher,

src/shrpx_tls.cc

@@ -1929,9 +1929,8 @@ ssize_t get_x509_fingerprint(uint8_t *dst, size_t dstlen, const X509 *x,
   return len;
 }
 
-StringRef get_x509_subject_name(BlockAllocator &balloc, X509 *x) {
-  auto nm = X509_get_subject_name(x);
-
+namespace {
+StringRef get_x509_name(BlockAllocator &balloc, X509_NAME *nm) {
   auto b = BIO_new(BIO_s_mem());
   if (!b) {
     return StringRef{};
@@ -1950,6 +1949,15 @@ StringRef get_x509_subject_name(BlockAllocator &balloc, X509 *x) {
   iov.base[slen] = '\0';
   return StringRef{iov.base, static_cast<size_t>(slen)};
 }
+} // namespace
+
+StringRef get_x509_subject_name(BlockAllocator &balloc, X509 *x) {
+  return get_x509_name(balloc, X509_get_subject_name(x));
+}
+
+StringRef get_x509_issuer_name(BlockAllocator &balloc, X509 *x) {
+  return get_x509_name(balloc, X509_get_issuer_name(x));
+}
 
 } // namespace tls
 

src/shrpx_tls.h

@@ -280,6 +280,10 @@ ssize_t get_x509_fingerprint(uint8_t *dst, size_t dstlen, const X509 *x,
 // name, it returns an empty string.
 StringRef get_x509_subject_name(BlockAllocator &balloc, X509 *x);
 
+// Returns issuer name of |x|.  If this function fails to get issuer
+// name, it returns an empty string.
+StringRef get_x509_issuer_name(BlockAllocator &balloc, X509 *x);
+
 } // namespace tls
 
 } // namespace shrpx