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 an 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 | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) diff --git a/tools/testing/vsock/vsock_test.c b/tools/testing/vsock/vsock_test.c index bdb0754965df..ab387a13f0ae 100644 --- a/tools/testing/vsock/vsock_test.c +++ b/tools/testing/vsock/vsock_test.c @@ -346,6 +346,38 @@ static void test_stream_msg_peek_server(const struct test_opts *opts) return test_msg_peek_server(opts, false); } +static void test_stream_peek_after_recv_server(const struct test_opts *opts) +{ + unsigned char buf_normal[MSG_PEEK_BUF_LEN]; + unsigned char buf_peek[MSG_PEEK_BUF_LEN]; + 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_normal, 1, 0, 1); + + /* Ask more bytes than available */ + recv_buf(fd, buf_peek, sizeof(buf_peek), MSG_PEEK, sizeof(buf_peek) - 1); + + /* Recv rest of the data */ + recv_buf(fd, buf_normal, sizeof(buf_normal) - 1, 0, sizeof(buf_normal) - 1); + + /* Compare full peek and normal read. */ + if (memcmp(buf_peek, buf_normal, sizeof(buf_peek) - 1)) { + fprintf(stderr, "Full peek data mismatch\n"); + exit(EXIT_FAILURE); + } + + close(fd); +} + #define SOCK_BUF_SIZE (2 * 1024 * 1024) #define SOCK_BUF_SIZE_SMALL (64 * 1024) #define MAX_MSG_PAGES 4 @@ -2509,6 +2541,11 @@ 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_msg_peek_client, + .run_server = test_stream_peek_after_recv_server, + }, {}, }; -- 2.53.0
