Fix grpc_sockaddr_to_uri to handle embedded nulls for unix_abstract resolved addresses (#29323)

Currently when an embedded null is present, it is left as is. This causes an issue when grpc_sockaddr_to_uri is followed by any c style operations like copy, as the string is truncated at the non-encoded null character. For example this is triggered when channel args containing a string channel arg is copied.

To prevent this properly encode the URI with %00.

BUILD

@@ -1739,6 +1739,7 @@ grpc_cc_library(
         "gpr_base",
         "grpc_sockaddr",
         "resolved_address",
+        "uri_parser",
     ],
 )
 

src/core/lib/address_utils/sockaddr_utils.cc

@@ -29,6 +29,7 @@
 #include "absl/status/status.h"
 #include "absl/strings/str_cat.h"
 #include "absl/strings/str_format.h"
+#include "absl/strings/str_replace.h"
 
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
@@ -37,6 +38,7 @@
 #include "src/core/lib/gprpp/host_port.h"
 #include "src/core/lib/iomgr/sockaddr.h"
 #include "src/core/lib/iomgr/socket_utils.h"
+#include "src/core/lib/uri/uri_parser.h"
 
 #ifdef GRPC_HAVE_UNIX_SOCKET
 #include <sys/un.h>
@@ -52,14 +54,20 @@ static absl::StatusOr<std::string> grpc_sockaddr_to_uri_unix_if_possible(
         absl::StrCat("Socket family is not AF_UNIX: ", addr->sa_family));
   }
   const auto* unix_addr = reinterpret_cast<const struct sockaddr_un*>(addr);
+  std::string scheme, path;
   if (unix_addr->sun_path[0] == '\0' && unix_addr->sun_path[1] != '\0') {
-    return absl::StrCat(
-        "unix-abstract:",
-        absl::string_view(
-            unix_addr->sun_path + 1,
-            resolved_addr->len - sizeof(unix_addr->sun_family) - 1));
+    scheme = "unix-abstract";
+    path = std::string(unix_addr->sun_path + 1,
+                       resolved_addr->len - sizeof(unix_addr->sun_family) - 1);
+  } else {
+    scheme = "unix";
+    path = unix_addr->sun_path;
   }
-  return absl::StrCat("unix:", unix_addr->sun_path);
+  absl::StatusOr<grpc_core::URI> uri = grpc_core::URI::Create(
+      std::move(scheme), /*authority=*/"", std::move(path),
+      /*query_parameter_pairs=*/{}, /*fragment=*/"");
+  if (!uri.ok()) return uri.status();
+  return uri->ToString();
 }
 #else
 static absl::StatusOr<std::string> grpc_sockaddr_to_uri_unix_if_possible(
@@ -263,6 +271,8 @@ absl::StatusOr<std::string> grpc_sockaddr_to_uri(
   if (scheme == nullptr || strcmp("unix", scheme) == 0) {
     return grpc_sockaddr_to_uri_unix_if_possible(resolved_addr);
   }
+  // TODO(anramach): Encode the string using URI::Create() and URI::ToString()
+  // before returning.
   auto path = grpc_sockaddr_to_string(resolved_addr, false /* normalize */);
   if (!path.ok()) return path;
   return absl::StrCat(scheme, ":", path.value());

test/core/address_utils/sockaddr_utils_test.cc

@@ -256,6 +256,27 @@ TEST(SockAddrUtilsTest, SockAddrToString) {
 #endif
 }
 
+#ifdef GRPC_HAVE_UNIX_SOCKET
+
+TEST(SockAddrUtilsTest, UnixSockAddrToUri) {
+  grpc_resolved_address addr;
+  ASSERT_TRUE(GRPC_ERROR_NONE ==
+              grpc_core::UnixSockaddrPopulate("sample-path", &addr));
+  EXPECT_EQ(grpc_sockaddr_to_uri(&addr).value(), "unix:sample-path");
+
+  ASSERT_TRUE(GRPC_ERROR_NONE ==
+              grpc_core::UnixAbstractSockaddrPopulate("no-nulls", &addr));
+  EXPECT_EQ(grpc_sockaddr_to_uri(&addr).value(), "unix-abstract:no-nulls");
+
+  ASSERT_TRUE(GRPC_ERROR_NONE ==
+              grpc_core::UnixAbstractSockaddrPopulate(
+                  std::string("path_\0with_null", 15), &addr));
+  EXPECT_EQ(grpc_sockaddr_to_uri(&addr).value(),
+            "unix-abstract:path_%00with_null");
+}
+
+#endif /* GRPC_HAVE_UNIX_SOCKET */
+
 TEST(SockAddrUtilsTest, SockAddrSetGetPort) {
   grpc_resolved_address input4 = MakeAddr4(kIPv4, sizeof(kIPv4));
   ASSERT_EQ(grpc_sockaddr_get_port(&input4), 12345);