Virtualization - Mar 2022 - [RFC PATCH v2 2/2] af_vsock: SOCK_SEQPACKET broken buffer test

On Wed, Mar 16, 2022 at 07:29:28AM +0000, Krasnov Arseniy Vladimirovich
wrote:
>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: Arseniy Krasnov <AVKrasnov at sberdevices.ru>
>---
> v1 -> v2:
> 1) Use 'fprintf()' instead of 'perror()' where
'errno' variable
>    is not affected.
> 2) Replace word "invalid" -> "unexpected".
>
> tools/testing/vsock/vsock_test.c | 132 +++++++++++++++++++++++++++++++
> 1 file changed, 132 insertions(+)
>
>diff --git a/tools/testing/vsock/vsock_test.c
b/tools/testing/vsock/vsock_test.c
>index 6d7648cce5aa..1132bcd8ddb7 100644
>--- a/tools/testing/vsock/vsock_test.c
>+++ b/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"
>@@ -465,6 +466,132 @@ 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 == NULL) {
>+		perror("'malloc()' for 'buf1'");
>+		exit(EXIT_FAILURE);
>+	}
>+
>+	buf2 = malloc(buf_size);
>+	if (buf2 == NULL) {
>+		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), got %zi, expected %i\n",
>+			res, buf_size);
I would suggest to use always the same pattern in the error messages:
"expected X, got Y".

The rest LGTM.
>+		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",
>@@ -510,6 +637,11 @@ 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,
>+	},
> 	{},
> };
>
>-- 
>2.25.1