gvisor/sock/unix: pass creds when a message is sent between unconnected sockets

and don't report a sender address if it doesn't have one

PiperOrigin-RevId: 251371284

2 files changed, 25 insertions, 13 deletions

diff --git a/test/syscalls/linux/accept_bind.cc b/test/syscalls/linux/accept_bind.cc
index 56377feab..1122ea240 100644
--- a/test/syscalls/linux/accept_bind.cc
+++ b/test/syscalls/linux/accept_bind.cc
@@ -448,19 +448,7 @@ TEST_P(AllSocketPairTest, UnboundSenderAddr) {
       RetryEINTR(recvfrom)(accepted_fd.get(), &i, sizeof(i), 0,
                            reinterpret_cast<sockaddr*>(&addr), &addr_len),
       SyscallSucceedsWithValue(sizeof(i)));
-  if (!IsRunningOnGvisor()) {
-    // Linux returns a zero length for addresses from recvfrom(2) and
-    // recvmsg(2). This differs from the behavior of getpeername(2) and
-    // getsockname(2). For simplicity, we use the getpeername(2) and
-    // getsockname(2) behavior for recvfrom(2) and recvmsg(2).
-    EXPECT_EQ(addr_len, 0);
-    return;
-  }
-  EXPECT_EQ(addr_len, 2);
-  EXPECT_EQ(
-      memcmp(&addr, sockets->second_addr(),
-             std::min((size_t)addr_len, (size_t)sockets->second_addr_len())),
-      0);
+  EXPECT_EQ(addr_len, 0);
 }
 
 TEST_P(AllSocketPairTest, BoundSenderAddr) {
diff --git a/test/syscalls/linux/socket_unix_unbound_dgram.cc b/test/syscalls/linux/socket_unix_unbound_dgram.cc
index 2ddc5c11f..52aef891f 100644
--- a/test/syscalls/linux/socket_unix_unbound_dgram.cc
+++ b/test/syscalls/linux/socket_unix_unbound_dgram.cc
@@ -13,7 +13,9 @@
 // limitations under the License.
 
 #include <stdio.h>
+#include <sys/socket.h>
 #include <sys/un.h>
+
 #include "gtest/gtest.h"
 #include "gtest/gtest.h"
 #include "test/syscalls/linux/socket_test_util.h"
@@ -142,6 +144,28 @@ TEST_P(UnboundDgramUnixSocketPairTest, SendtoWithoutConnect) {
       SyscallSucceedsWithValue(sizeof(data)));
 }
 
+TEST_P(UnboundDgramUnixSocketPairTest, SendtoWithoutConnectPassCreds) {
+  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());
+
+  ASSERT_THAT(bind(sockets->first_fd(), sockets->first_addr(),
+                   sockets->first_addr_size()),
+              SyscallSucceeds());
+
+  SetSoPassCred(sockets->first_fd());
+  char data = 'a';
+  ASSERT_THAT(
+      RetryEINTR(sendto)(sockets->second_fd(), &data, sizeof(data), 0,
+                         sockets->first_addr(), sockets->first_addr_size()),
+      SyscallSucceedsWithValue(sizeof(data)));
+  ucred creds;
+  creds.pid = -1;
+  char buf[sizeof(data) + 1];
+  ASSERT_NO_FATAL_FAILURE(
+      RecvCreds(sockets->first_fd(), &creds, buf, sizeof(buf), sizeof(data)));
+  EXPECT_EQ(0, memcmp(&data, buf, sizeof(data)));
+  EXPECT_THAT(getpid(), SyscallSucceedsWithValue(creds.pid));
+}
+
 INSTANTIATE_TEST_SUITE_P(
     AllUnixDomainSockets, UnboundDgramUnixSocketPairTest,
     ::testing::ValuesIn(VecCat<SocketPairKind>(