[LTP] [PATCH v2] syscalls/connect02: Handle IPV6_ADDRFORM removal and listen() EINVAL

[Ramesh Chhetri]

Upstream kernel commit 31c5ea8a3296 ("ipv6: Remove IPV6_ADDRFORM.") completely
removed IPV6_ADDRFORM socket option support from the Linux kernel, causing
setsockopt(SOL_IPV6, IPV6_ADDRFORM, ...) to return -ENOPROTOOPT.

In addition, commit 8cc3aef0cb19 ("tcp: Do not allow buggy transitions between
ehash and lhash2.") intentionally disallows converting an unhashed established
socket into a listening socket by returning -EINVAL from listen().

Update connect02 to:
1. Probe getsockopt(IPV6_ADDRFORM) on ENOPROTOOPT failure to distinguish true
   kernel removal from the known regression fixed by 82c9ae440857, reporting
   TCONF only if the option is truly absent.
2. Report TCONF when listen() returns EINVAL due to the unhashed socket
   transition restriction.

Signed-off-by: Ramesh Chhetri <rameshch@linux.ibm.com>
---
V1 -> V2:
- Distinguish IPV6_ADDRFORM removal from CVE-2018-9568 regression (commit
  b6f6118901d1) via getsockopt() probe to retain TFAIL on buggy kernels.
- Report TCONF instead of TPASS when listen() returns EINVAL.
- Initialize 'family' to 0 and ensure sockets are closed on exit paths.

 testcases/kernel/syscalls/connect/connect02.c | 27 ++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/testcases/kernel/syscalls/connect/connect02.c b/testcases/kernel/syscalls/connect/connect02.c
index 079bc5bca..74e2022bb 100644
--- a/testcases/kernel/syscalls/connect/connect02.c
+++ b/testcases/kernel/syscalls/connect/connect02.c
@@ -91,6 +91,21 @@ static void run(void)
 			sizeof(optval)));

 		if (TST_RET == -1) {
+			if (TST_ERR == ENOPROTOOPT || TST_ERR == EOPNOTSUPP) {
+				int family = 0;
+				socklen_t optlen = sizeof(family);
+
+				if (getsockopt(fd, SOL_IPV6, IPV6_ADDRFORM,
+					&family, &optlen) == -1 && errno == ENOPROTOOPT) {
+					SAFE_CLOSE(confd1);
+					SAFE_CLOSE(fd);
+					tst_brk(TCONF | TTERRNO,
+						"IPV6_ADDRFORM is removed/unsupported by this kernel");
+				}
+			}
+
+			SAFE_CLOSE(confd1);
+			SAFE_CLOSE(fd);
 			tst_res(TFAIL | TTERRNO,
 				"setsockopt(IPV6_ADDRFORM) failed");
 			return;
@@ -104,7 +119,17 @@ static void run(void)
 			sizeof(reset_addr));
 		SAFE_BIND(fd, (struct sockaddr *)&bind_addr4,
 			sizeof(bind_addr4));
-		SAFE_LISTEN(fd, 5);
+		TEST(listen(fd, 5));
+		if (TST_RET == -1) {
+			SAFE_CLOSE(confd1);
+			SAFE_CLOSE(fd);
+
+			if (TST_ERR == EINVAL) {
+				tst_brk(TCONF,
+					"Transition from unhashed established socket to listening is disallowed");
+			}
+			tst_brk(TBROK | TTERRNO, "listen(fd,5) failed unexpectedly");
+		}

 		addrlen = tst_get_connect_address(fd, &client_addr2);
 		confd2 = SAFE_SOCKET(AF_INET, SOCK_STREAM, IPPROTO_TCP);
--
2.56.0