af_vsock: SOCK_SEQPACKET broken buffer test

Add test where sender sends two message, each with own
data pattern. Reader tries to read first to broken buffer:
it has three pages size, but middle page is unmapped. Then,
reader tries to read second message to valid buffer. Test
checks, that uncopied part of first message was dropped
and thus not copied as part of second message.
Signed-off-by: Krasnov Arseniy Vladimirovich <AVKrasnov@sberdevices.ru>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/vsock/vsock_test.c

@@ -17,6 +17,7 @@
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <time.h>
+#include <sys/mman.h>
 
 #include "timeout.h"
 #include "control.h"
@@ -470,6 +471,131 @@ static void test_seqpacket_timeout_server(const struct test_opts *opts)
 	close(fd);
 }
 
+#define BUF_PATTERN_1 'a'
+#define BUF_PATTERN_2 'b'
+
+static void test_seqpacket_invalid_rec_buffer_client(const struct test_opts *opts)
+{
+	int fd;
+	unsigned char *buf1;
+	unsigned char *buf2;
+	int buf_size = getpagesize() * 3;
+
+	fd = vsock_seqpacket_connect(opts->peer_cid, 1234);
+	if (fd < 0) {
+		perror("connect");
+		exit(EXIT_FAILURE);
+	}
+
+	buf1 = malloc(buf_size);
+	if (!buf1) {
+		perror("'malloc()' for 'buf1'");
+		exit(EXIT_FAILURE);
+	}
+
+	buf2 = malloc(buf_size);
+	if (!buf2) {
+		perror("'malloc()' for 'buf2'");
+		exit(EXIT_FAILURE);
+	}
+
+	memset(buf1, BUF_PATTERN_1, buf_size);
+	memset(buf2, BUF_PATTERN_2, buf_size);
+
+	if (send(fd, buf1, buf_size, 0) != buf_size) {
+		perror("send failed");
+		exit(EXIT_FAILURE);
+	}
+
+	if (send(fd, buf2, buf_size, 0) != buf_size) {
+		perror("send failed");
+		exit(EXIT_FAILURE);
+	}
+
+	close(fd);
+}
+
+static void test_seqpacket_invalid_rec_buffer_server(const struct test_opts *opts)
+{
+	int fd;
+	unsigned char *broken_buf;
+	unsigned char *valid_buf;
+	int page_size = getpagesize();
+	int buf_size = page_size * 3;
+	ssize_t res;
+	int prot = PROT_READ | PROT_WRITE;
+	int flags = MAP_PRIVATE | MAP_ANONYMOUS;
+	int i;
+
+	fd = vsock_seqpacket_accept(VMADDR_CID_ANY, 1234, NULL);
+	if (fd < 0) {
+		perror("accept");
+		exit(EXIT_FAILURE);
+	}
+
+	/* Setup first buffer. */
+	broken_buf = mmap(NULL, buf_size, prot, flags, -1, 0);
+	if (broken_buf == MAP_FAILED) {
+		perror("mmap for 'broken_buf'");
+		exit(EXIT_FAILURE);
+	}
+
+	/* Unmap "hole" in buffer. */
+	if (munmap(broken_buf + page_size, page_size)) {
+		perror("'broken_buf' setup");
+		exit(EXIT_FAILURE);
+	}
+
+	valid_buf = mmap(NULL, buf_size, prot, flags, -1, 0);
+	if (valid_buf == MAP_FAILED) {
+		perror("mmap for 'valid_buf'");
+		exit(EXIT_FAILURE);
+	}
+
+	/* Try to fill buffer with unmapped middle. */
+	res = read(fd, broken_buf, buf_size);
+	if (res != -1) {
+		fprintf(stderr,
+			"expected 'broken_buf' read(2) failure, got %zi\n",
+			res);
+		exit(EXIT_FAILURE);
+	}
+
+	if (errno != ENOMEM) {
+		perror("unexpected errno of 'broken_buf'");
+		exit(EXIT_FAILURE);
+	}
+
+	/* Try to fill valid buffer. */
+	res = read(fd, valid_buf, buf_size);
+	if (res < 0) {
+		perror("unexpected 'valid_buf' read(2) failure");
+		exit(EXIT_FAILURE);
+	}
+
+	if (res != buf_size) {
+		fprintf(stderr,
+			"invalid 'valid_buf' read(2), expected %i, got %zi\n",
+			buf_size, res);
+		exit(EXIT_FAILURE);
+	}
+
+	for (i = 0; i < buf_size; i++) {
+		if (valid_buf[i] != BUF_PATTERN_2) {
+			fprintf(stderr,
+				"invalid pattern for 'valid_buf' at %i, expected %hhX, got %hhX\n",
+				i, BUF_PATTERN_2, valid_buf[i]);
+			exit(EXIT_FAILURE);
+		}
+	}
+
+	/* Unmap buffers. */
+	munmap(broken_buf, page_size);
+	munmap(broken_buf + page_size * 2, page_size);
+	munmap(valid_buf, buf_size);
+	close(fd);
+}
+
 static struct test_case test_cases[] = {
 	{
 		.name = "SOCK_STREAM connection reset",
@@ -515,6 +641,11 @@ static struct test_case test_cases[] = {
 		.run_client = test_seqpacket_timeout_client,
 		.run_server = test_seqpacket_timeout_server,
 	},
+	{
+		.name = "SOCK_SEQPACKET invalid receive buffer",
+		.run_client = test_seqpacket_invalid_rec_buffer_client,
+		.run_server = test_seqpacket_invalid_rec_buffer_server,
+	},
 	{},
 };