Add a test that verifies MSG_PEEK works correctly after a partial recv(). This is to test a bug that was present in the `virtio_transport_stream_do_peek()` when computing the number of bytes to copy: After a partial read, the peek function didn't take into consideration the number of bytes that were already read. So peeking the whole buffer would cause a out-of-bounds read, that resulted in a -EFAULT.
This test does exactly this: do a partial recv on a buffer, then try to peek the whole buffer content. Signed-off-by: Luigi Leonardi <[email protected]> --- tools/testing/vsock/vsock_test.c | 64 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 64 insertions(+) diff --git a/tools/testing/vsock/vsock_test.c b/tools/testing/vsock/vsock_test.c index 5bd20ccd9335caafe68e8b7a5d02a4deb3d2deec..308f9f8f30d22bec5aaa282356e400d8438fe321 100644 --- a/tools/testing/vsock/vsock_test.c +++ b/tools/testing/vsock/vsock_test.c @@ -346,6 +346,65 @@ static void test_stream_msg_peek_server(const struct test_opts *opts) return test_msg_peek_server(opts, false); } +#define PEEK_AFTER_RECV_LEN 100 + +static void test_stream_peek_after_recv_client(const struct test_opts *opts) +{ + unsigned char buf[PEEK_AFTER_RECV_LEN]; + int fd; + int i; + + fd = vsock_stream_connect(opts->peer_cid, opts->peer_port); + if (fd < 0) { + perror("connect"); + exit(EXIT_FAILURE); + } + + for (i = 0; i < sizeof(buf); i++) + buf[i] = (unsigned char)i; + + control_expectln("SRVREADY"); + + send_buf(fd, buf, sizeof(buf), 0, sizeof(buf)); + + close(fd); +} + +static void test_stream_peek_after_recv_server(const struct test_opts *opts) +{ + unsigned char buf[PEEK_AFTER_RECV_LEN]; + int half = PEEK_AFTER_RECV_LEN / 2; + ssize_t ret; + int fd; + + fd = vsock_stream_accept(VMADDR_CID_ANY, opts->peer_port, NULL); + if (fd < 0) { + perror("accept"); + exit(EXIT_FAILURE); + } + + control_writeln("SRVREADY"); + + /* Partial recv to advance offset within the skb */ + recv_buf(fd, buf, half, 0, half); + + /* Try to peek more than what remains: should return only 'half' + * bytes. Note: we can't use recv_buf() because it loops until + * all requested bytes are returned. + */ + ret = recv(fd, buf, sizeof(buf), MSG_PEEK); + if (ret < 0) { + perror("recv"); + exit(EXIT_FAILURE); + } else if (ret != half) { + fprintf(stderr, "MSG_PEEK after partial recv returned %d (expected %d)\n", + ret, half); + exit(EXIT_FAILURE); + } + + close(fd); +} + #define SOCK_BUF_SIZE (2 * 1024 * 1024) #define SOCK_BUF_SIZE_SMALL (64 * 1024) #define MAX_MSG_PAGES 4 @@ -2520,6 +2579,11 @@ static struct test_case test_cases[] = { .run_client = test_stream_tx_credit_bounds_client, .run_server = test_stream_tx_credit_bounds_server, }, + { + .name = "SOCK_STREAM MSG_PEEK after partial recv", + .run_client = test_stream_peek_after_recv_client, + .run_server = test_stream_peek_after_recv_server, + }, {}, }; -- 2.53.0
