Loopback transport can mangle data in rx queue when a linear skb is followed by a small MSG_ZEROCOPY packet.
To exercise the logic, send out two packets: a weirdly sized one (to ensure some spare tail room in the skb) and a zerocopy one that's small enough to fit in the spare room of its predecessor. Then, wait for both to land in the rx queue, and check the data received. Faulty packets merger manifests itself by corrupting payload of the later packet. Signed-off-by: Michal Luczaj <[email protected]> --- tools/testing/vsock/vsock_test.c | 5 +++ tools/testing/vsock/vsock_test_zerocopy.c | 74 +++++++++++++++++++++++++++++++ tools/testing/vsock/vsock_test_zerocopy.h | 3 ++ 3 files changed, 82 insertions(+) diff --git a/tools/testing/vsock/vsock_test.c b/tools/testing/vsock/vsock_test.c index bbe3723babdc..27e39354499a 100644 --- a/tools/testing/vsock/vsock_test.c +++ b/tools/testing/vsock/vsock_test.c @@ -2403,6 +2403,11 @@ static struct test_case test_cases[] = { .run_client = test_stream_accepted_setsockopt_client, .run_server = test_stream_accepted_setsockopt_server, }, + { + .name = "SOCK_STREAM virtio MSG_ZEROCOPY coalescence corruption", + .run_client = test_stream_msgzcopy_mangle_client, + .run_server = test_stream_msgzcopy_mangle_server, + }, {}, }; diff --git a/tools/testing/vsock/vsock_test_zerocopy.c b/tools/testing/vsock/vsock_test_zerocopy.c index 9d9a6cb9614a..a31ddfc1cd0c 100644 --- a/tools/testing/vsock/vsock_test_zerocopy.c +++ b/tools/testing/vsock/vsock_test_zerocopy.c @@ -9,14 +9,18 @@ #include <stdio.h> #include <stdlib.h> #include <string.h> +#include <sys/ioctl.h> #include <sys/mman.h> #include <unistd.h> #include <poll.h> #include <linux/errqueue.h> #include <linux/kernel.h> +#include <linux/sockios.h> +#include <linux/time64.h> #include <errno.h> #include "control.h" +#include "timeout.h" #include "vsock_test_zerocopy.h" #include "msg_zerocopy_common.h" @@ -356,3 +360,73 @@ void test_stream_msgzcopy_empty_errq_server(const struct test_opts *opts) control_expectln("DONE"); close(fd); } + +#define GOOD_COPY_LEN 128 /* net/vmw_vsock/virtio_transport_common.c */ + +void test_stream_msgzcopy_mangle_client(const struct test_opts *opts) +{ + char sbuf1[PAGE_SIZE + 1], sbuf2[GOOD_COPY_LEN]; + unsigned long hash; + struct pollfd fds; + int fd, i; + + fd = vsock_stream_connect(opts->peer_cid, opts->peer_port); + if (fd < 0) { + perror("connect"); + exit(EXIT_FAILURE); + } + + enable_so_zerocopy_check(fd); + + memset(sbuf1, 'x', sizeof(sbuf1)); + send_buf(fd, sbuf1, sizeof(sbuf1), 0, sizeof(sbuf1)); + + for (i = 0; i < sizeof(sbuf2); i++) + sbuf2[i] = rand() & 0xff; + + send_buf(fd, sbuf2, sizeof(sbuf2), MSG_ZEROCOPY, sizeof(sbuf2)); + + hash = hash_djb2(sbuf2, sizeof(sbuf2)); + control_writeulong(hash); + + fds.fd = fd; + fds.events = 0; + + if (poll(&fds, 1, TIMEOUT * MSEC_PER_SEC) != 1 || + !(fds.revents & POLLERR)) { + perror("poll"); + exit(EXIT_FAILURE); + } + + close(fd); +} + +void test_stream_msgzcopy_mangle_server(const struct test_opts *opts) +{ + unsigned long local_hash, remote_hash; + char rbuf[PAGE_SIZE + 1]; + int fd; + + fd = vsock_stream_accept(VMADDR_CID_ANY, opts->peer_port, NULL); + if (fd < 0) { + perror("accept"); + exit(EXIT_FAILURE); + } + + /* Wait, don't race the (buggy) skbs coalescence. */ + vsock_ioctl_int(fd, SIOCINQ, PAGE_SIZE + 1 + GOOD_COPY_LEN); + + /* Discard the first packet. */ + recv_buf(fd, rbuf, PAGE_SIZE + 1, 0, PAGE_SIZE + 1); + + recv_buf(fd, rbuf, GOOD_COPY_LEN, 0, GOOD_COPY_LEN); + remote_hash = control_readulong(); + local_hash = hash_djb2(rbuf, GOOD_COPY_LEN); + + if (local_hash != remote_hash) { + fprintf(stderr, "Data received corrupted\n"); + exit(EXIT_FAILURE); + } + + close(fd); +} diff --git a/tools/testing/vsock/vsock_test_zerocopy.h b/tools/testing/vsock/vsock_test_zerocopy.h index 3ef2579e024d..d46c91a69f16 100644 --- a/tools/testing/vsock/vsock_test_zerocopy.h +++ b/tools/testing/vsock/vsock_test_zerocopy.h @@ -12,4 +12,7 @@ void test_seqpacket_msgzcopy_server(const struct test_opts *opts); void test_stream_msgzcopy_empty_errq_client(const struct test_opts *opts); void test_stream_msgzcopy_empty_errq_server(const struct test_opts *opts); +void test_stream_msgzcopy_mangle_client(const struct test_opts *opts); +void test_stream_msgzcopy_mangle_server(const struct test_opts *opts); + #endif /* VSOCK_TEST_ZEROCOPY_H */ -- 2.52.0
