selftests: tls: handful of memrnd() and length checks

Add a handful of memory randomizations and precise length checks.
Nothing is really broken here, I did this to increase confidence
when debugging. It does fix a GCC warning, tho. Apparently GCC
recognizes that memory needs to be initialized for send() but
does not recognize that for write().
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools/testing/selftests/net/tls.c

@@ -644,12 +644,14 @@ TEST_F(tls, splice_from_pipe2)
 	int p2[2];
 	int p[2];
 
+	memrnd(mem_send, sizeof(mem_send));
+
 	ASSERT_GE(pipe(p), 0);
 	ASSERT_GE(pipe(p2), 0);
-	EXPECT_GE(write(p[1], mem_send, 8000), 0);
-	EXPECT_GE(splice(p[0], NULL, self->fd, NULL, 8000, 0), 0);
-	EXPECT_GE(write(p2[1], mem_send + 8000, 8000), 0);
-	EXPECT_GE(splice(p2[0], NULL, self->fd, NULL, 8000, 0), 0);
+	EXPECT_EQ(write(p[1], mem_send, 8000), 8000);
+	EXPECT_EQ(splice(p[0], NULL, self->fd, NULL, 8000, 0), 8000);
+	EXPECT_EQ(write(p2[1], mem_send + 8000, 8000), 8000);
+	EXPECT_EQ(splice(p2[0], NULL, self->fd, NULL, 8000, 0), 8000);
 	EXPECT_EQ(recv(self->cfd, mem_recv, send_len, MSG_WAITALL), send_len);
 	EXPECT_EQ(memcmp(mem_send, mem_recv, send_len), 0);
 }
@@ -683,10 +685,12 @@ TEST_F(tls, splice_to_pipe)
 	char mem_recv[TLS_PAYLOAD_MAX_LEN];
 	int p[2];
 
+	memrnd(mem_send, sizeof(mem_send));
+
 	ASSERT_GE(pipe(p), 0);
-	EXPECT_GE(send(self->fd, mem_send, send_len, 0), 0);
-	EXPECT_GE(splice(self->cfd, NULL, p[1], NULL, send_len, 0), 0);
-	EXPECT_GE(read(p[0], mem_recv, send_len), 0);
+	EXPECT_EQ(send(self->fd, mem_send, send_len, 0), send_len);
+	EXPECT_EQ(splice(self->cfd, NULL, p[1], NULL, send_len, 0), send_len);
+	EXPECT_EQ(read(p[0], mem_recv, send_len), send_len);
 	EXPECT_EQ(memcmp(mem_send, mem_recv, send_len), 0);
 }
 
@@ -875,6 +879,8 @@ TEST_F(tls, multiple_send_single_recv)
 	char recv_mem[2 * 10];
 	char send_mem[10];
 
+	memrnd(send_mem, sizeof(send_mem));
+
 	EXPECT_GE(send(self->fd, send_mem, send_len, 0), 0);
 	EXPECT_GE(send(self->fd, send_mem, send_len, 0), 0);
 	memset(recv_mem, 0, total_len);
@@ -891,6 +897,8 @@ TEST_F(tls, single_send_multiple_recv_non_align)
 	char recv_mem[recv_len * 2];
 	char send_mem[total_len];
 
+	memrnd(send_mem, sizeof(send_mem));
+
 	EXPECT_GE(send(self->fd, send_mem, total_len, 0), 0);
 	memset(recv_mem, 0, total_len);
 
@@ -936,10 +944,10 @@ TEST_F(tls, recv_peek)
 	char buf[15];
 
 	EXPECT_EQ(send(self->fd, test_str, send_len, 0), send_len);
-	EXPECT_NE(recv(self->cfd, buf, send_len, MSG_PEEK), -1);
+	EXPECT_EQ(recv(self->cfd, buf, send_len, MSG_PEEK), send_len);
 	EXPECT_EQ(memcmp(test_str, buf, send_len), 0);
 	memset(buf, 0, sizeof(buf));
-	EXPECT_NE(recv(self->cfd, buf, send_len, 0), -1);
+	EXPECT_EQ(recv(self->cfd, buf, send_len, 0), send_len);
 	EXPECT_EQ(memcmp(test_str, buf, send_len), 0);
 }