[RFC,v1,16/16] vsock_test: SEQPACKET read to broken buffer

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: Arseny Krasnov <arseny.krasnov@kaspersky.com>
---
 tools/testing/vsock/vsock_test.c | 121 +++++++++++++++++++++++++++++++
 1 file changed, 121 insertions(+)

On Mon, Jun 28, 2021 at 01:05:36PM +0300, Arseny Krasnov 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: Arseny Krasnov <arseny.krasnov@kaspersky.com>

>---

> tools/testing/vsock/vsock_test.c | 121 +++++++++++++++++++++++++++++++

> 1 file changed, 121 insertions(+)


Cool test! Thanks for doing this!

>

>diff --git a/tools/testing/vsock/vsock_test.c b/tools/testing/vsock/vsock_test.c

>index 67766bfe176f..697ba168e97f 100644

>--- a/tools/testing/vsock/vsock_test.c

>+++ b/tools/testing/vsock/vsock_test.c

>@@ -16,6 +16,7 @@

> #include <linux/kernel.h>

> #include <sys/types.h>

> #include <sys/socket.h>

>+#include <sys/mman.h>

>

> #include "timeout.h"

> #include "control.h"

>@@ -385,6 +386,121 @@ static void test_seqpacket_msg_trunc_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) {


checkpatch suggests to use "if (!buf1)" ...

>+              perror("'malloc()' for 'buf1'");

>+              exit(EXIT_FAILURE);

>+      }

>+

>+      buf2 = malloc(buf_size);

>+      if (buf2 == NULL) {


... and "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) {

>+              perror("invalid read result of 'broken_buf'");

>+              exit(EXIT_FAILURE);

>+      }

>+

>+      if (errno != ENOMEM) {

>+              perror("invalid errno of 'broken_buf'");

>+              exit(EXIT_FAILURE);

>+      }

>+

>+      /* Try to fill valid buffer. */

>+      res = read(fd, valid_buf, buf_size);

>+      if (res != buf_size) {

>+              perror("invalid read result of 'valid_buf'");

>+              exit(EXIT_FAILURE);

>+      }

>+

>+      for (i = 0; i < buf_size; i++) {

>+              if (valid_buf[i] != BUF_PATTERN_2) {

>+                      perror("invalid pattern for valid buf");

>+                      exit(EXIT_FAILURE);

>+              }

>+      }

>+

>+


... and to remove the extra blank line here :-)

Thanks,
Stefano

>+      /* 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",

>@@ -425,6 +541,11 @@ static struct test_case test_cases[] = {

>               .run_client = test_seqpacket_msg_trunc_client,

>               .run_server = test_seqpacket_msg_trunc_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

>