From f7154d967bc4ee25ea1572937550e711b2525474 Mon Sep 17 00:00:00 2001 From: Arseniy Krasnov Date: Tue, 28 Mar 2023 14:31:28 +0300 Subject: virtio/vsock: fix header length on skb merging This fixes appending newly arrived skbuff to the last skbuff of the socket's queue. Problem fires when we are trying to append data to skbuff which was already processed in dequeue callback at least once. Dequeue callback calls function 'skb_pull()' which changes 'skb->len'. In current implementation 'skb->len' is used to update length in header of the last skbuff after new data was copied to it. This is bug, because value in header is used to calculate 'rx_bytes'/'fwd_cnt' and thus must be not be changed during skbuff's lifetime. Bug starts to fire since: commit 077706165717 ("virtio/vsock: don't use skbuff state to account credit") It presents before, but didn't triggered due to a little bit buggy implementation of credit calculation logic. So use Fixes tag for it. Fixes: 077706165717 ("virtio/vsock: don't use skbuff state to account credit") Signed-off-by: Arseniy Krasnov Reviewed-by: Stefano Garzarella Signed-off-by: Paolo Abeni --- net/vmw_vsock/virtio_transport_common.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c index 6564192e7f20..11ca9b3362aa 100644 --- a/net/vmw_vsock/virtio_transport_common.c +++ b/net/vmw_vsock/virtio_transport_common.c @@ -1068,7 +1068,7 @@ virtio_transport_recv_enqueue(struct vsock_sock *vsk, memcpy(skb_put(last_skb, skb->len), skb->data, skb->len); free_pkt = true; last_hdr->flags |= hdr->flags; - last_hdr->len = cpu_to_le32(last_skb->len); + le32_add_cpu(&last_hdr->len, len); goto out; } } -- cgit From b8d2f61fdf2a566f7872158f35e65599aceb90fb Mon Sep 17 00:00:00 2001 From: Arseniy Krasnov Date: Tue, 28 Mar 2023 14:32:12 +0300 Subject: virtio/vsock: WARN_ONCE() for invalid state of socket This adds WARN_ONCE() and return from stream dequeue callback when socket's queue is empty, but 'rx_bytes' still non-zero. This allows the detection of potential bugs due to packet merging (see previous patch). Signed-off-by: Arseniy Krasnov Reviewed-by: Stefano Garzarella Signed-off-by: Paolo Abeni --- net/vmw_vsock/virtio_transport_common.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c index 11ca9b3362aa..37934dfe72f4 100644 --- a/net/vmw_vsock/virtio_transport_common.c +++ b/net/vmw_vsock/virtio_transport_common.c @@ -363,6 +363,13 @@ virtio_transport_stream_do_dequeue(struct vsock_sock *vsk, u32 free_space; spin_lock_bh(&vvs->rx_lock); + + if (WARN_ONCE(skb_queue_empty(&vvs->rx_queue) && vvs->rx_bytes, + "rx_queue is empty, but rx_bytes is non-zero\n")) { + spin_unlock_bh(&vvs->rx_lock); + return err; + } + while (total < len && !skb_queue_empty(&vvs->rx_queue)) { skb = skb_peek(&vvs->rx_queue); -- cgit From 25209a3209ecc44f93300b7ee5287f451be1d6ff Mon Sep 17 00:00:00 2001 From: Arseniy Krasnov Date: Tue, 28 Mar 2023 14:33:07 +0300 Subject: test/vsock: new skbuff appending test This adds test which checks case when data of newly received skbuff is appended to the last skbuff in the socket's queue. It looks like simple test with 'send()' and 'recv()', but internally it triggers logic which appends one received skbuff to another. Test checks that this feature works correctly. This test is actual only for virtio transport. Signed-off-by: Arseniy Krasnov Reviewed-by: Stefano Garzarella Signed-off-by: Paolo Abeni --- tools/testing/vsock/vsock_test.c | 90 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 90 insertions(+) diff --git a/tools/testing/vsock/vsock_test.c b/tools/testing/vsock/vsock_test.c index 3de10dbb50f5..12b97c92fbb2 100644 --- a/tools/testing/vsock/vsock_test.c +++ b/tools/testing/vsock/vsock_test.c @@ -968,6 +968,91 @@ static void test_seqpacket_inv_buf_server(const struct test_opts *opts) test_inv_buf_server(opts, false); } +#define HELLO_STR "HELLO" +#define WORLD_STR "WORLD" + +static void test_stream_virtio_skb_merge_client(const struct test_opts *opts) +{ + ssize_t res; + int fd; + + fd = vsock_stream_connect(opts->peer_cid, 1234); + if (fd < 0) { + perror("connect"); + exit(EXIT_FAILURE); + } + + /* Send first skbuff. */ + res = send(fd, HELLO_STR, strlen(HELLO_STR), 0); + if (res != strlen(HELLO_STR)) { + fprintf(stderr, "unexpected send(2) result %zi\n", res); + exit(EXIT_FAILURE); + } + + control_writeln("SEND0"); + /* Peer reads part of first skbuff. */ + control_expectln("REPLY0"); + + /* Send second skbuff, it will be appended to the first. */ + res = send(fd, WORLD_STR, strlen(WORLD_STR), 0); + if (res != strlen(WORLD_STR)) { + fprintf(stderr, "unexpected send(2) result %zi\n", res); + exit(EXIT_FAILURE); + } + + control_writeln("SEND1"); + /* Peer reads merged skbuff packet. */ + control_expectln("REPLY1"); + + close(fd); +} + +static void test_stream_virtio_skb_merge_server(const struct test_opts *opts) +{ + unsigned char buf[64]; + ssize_t res; + int fd; + + fd = vsock_stream_accept(VMADDR_CID_ANY, 1234, NULL); + if (fd < 0) { + perror("accept"); + exit(EXIT_FAILURE); + } + + control_expectln("SEND0"); + + /* Read skbuff partially. */ + res = recv(fd, buf, 2, 0); + if (res != 2) { + fprintf(stderr, "expected recv(2) returns 2 bytes, got %zi\n", res); + exit(EXIT_FAILURE); + } + + control_writeln("REPLY0"); + control_expectln("SEND1"); + + res = recv(fd, buf + 2, sizeof(buf) - 2, 0); + if (res != 8) { + fprintf(stderr, "expected recv(2) returns 8 bytes, got %zi\n", res); + exit(EXIT_FAILURE); + } + + res = recv(fd, buf, sizeof(buf) - 8 - 2, MSG_DONTWAIT); + if (res != -1) { + fprintf(stderr, "expected recv(2) failure, got %zi\n", res); + exit(EXIT_FAILURE); + } + + if (memcmp(buf, HELLO_STR WORLD_STR, strlen(HELLO_STR WORLD_STR))) { + fprintf(stderr, "pattern mismatch\n"); + exit(EXIT_FAILURE); + } + + control_writeln("REPLY1"); + + close(fd); +} + static struct test_case test_cases[] = { { .name = "SOCK_STREAM connection reset", @@ -1038,6 +1123,11 @@ static struct test_case test_cases[] = { .run_client = test_seqpacket_inv_buf_client, .run_server = test_seqpacket_inv_buf_server, }, + { + .name = "SOCK_STREAM virtio skb merge", + .run_client = test_stream_virtio_skb_merge_client, + .run_server = test_stream_virtio_skb_merge_server, + }, {}, }; -- cgit