[Qemu-devel] [PATCH V2] test-filter-mirror: pass UNIX domain socket through fd

[Qemu-devel] [PATCH V2] test-filter-mirror: pass UNIX domain socket through fd

[Jason Wang]

The tests tries to let qemu server mode to process the connection
which turns out to be racy after commit 8258292e18c3 ("monitor: Remove
"x-oob", offer capability "oob" unconditionally"). This is because the
filter may try to mirror the packets before UNIX socket object is
ready (connected was set to true) from the view of qemu. In this case
the packet will be dropped silently.

Fixing this by passing pre-connected socket created by socketpair() to
qemu through fd.

Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: Li Zhijian <lizhijian@cn.fujitsu.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
Cc: Zhang Chen <zhangckid@gmail.com>
Cc: Markus Armbruster <armbru@redhat.com>
Cc: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
Changes from v1:
- close the socket pairs in the end of test
---
 tests/test-filter-mirror.c | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/tests/test-filter-mirror.c b/tests/test-filter-mirror.c
index 7ab2aed8a0..d942c74a3f 100644
--- a/tests/test-filter-mirror.c
+++ b/tests/test-filter-mirror.c
@@ -21,10 +21,9 @@
 
 static void test_mirror(void)
 {
-    int send_sock[2], recv_sock;
+    int send_sock[2], recv_sock[2];
     uint32_t ret = 0, len = 0;
     char send_buf[] = "Hello! filter-mirror~";
-    char sock_path[] = "filter-mirror.XXXXXX";
     char *recv_buf;
     uint32_t size = sizeof(send_buf);
     size = htonl(size);
@@ -38,18 +37,15 @@ static void test_mirror(void)
     ret = socketpair(PF_UNIX, SOCK_STREAM, 0, send_sock);
     g_assert_cmpint(ret, !=, -1);
 
-    ret = mkstemp(sock_path);
+    ret = socketpair(PF_UNIX, SOCK_STREAM, 0, recv_sock);
     g_assert_cmpint(ret, !=, -1);
 
     qts = qtest_initf(
         "-netdev socket,id=qtest-bn0,fd=%d "
         "-device %s,netdev=qtest-bn0,id=qtest-e0 "
-        "-chardev socket,id=mirror0,path=%s,server,nowait "
+        "-chardev socket,id=mirror0,fd=%d "
         "-object filter-mirror,id=qtest-f0,netdev=qtest-bn0,queue=tx,outdev=mirror0 "
-        , send_sock[1], devstr, sock_path);
-
-    recv_sock = unix_connect(sock_path, NULL);
-    g_assert_cmpint(recv_sock, !=, -1);
+        , send_sock[1], devstr, recv_sock[1]);
 
     struct iovec iov[] = {
         {
@@ -67,18 +63,20 @@ static void test_mirror(void)
     g_assert_cmpint(ret, ==, sizeof(send_buf) + sizeof(size));
     close(send_sock[0]);
 
-    ret = qemu_recv(recv_sock, &len, sizeof(len), 0);
+    ret = qemu_recv(recv_sock[0], &len, sizeof(len), 0);
     g_assert_cmpint(ret, ==, sizeof(len));
     len = ntohl(len);
 
     g_assert_cmpint(len, ==, sizeof(send_buf));
     recv_buf = g_malloc(len);
-    ret = qemu_recv(recv_sock, recv_buf, len, 0);
+    ret = qemu_recv(recv_sock[0], recv_buf, len, 0);
     g_assert_cmpstr(recv_buf, ==, send_buf);
 
     g_free(recv_buf);
-    close(recv_sock);
-    unlink(sock_path);
+    close(send_sock[0]);
+    close(send_sock[1]);
+    close(recv_sock[0]);
+    close(recv_sock[1]);
     qtest_quit(qts);
 }
 
-- 
2.17.1

Re: [Qemu-devel] [PATCH V2] test-filter-mirror: pass UNIX domain socket through fd

[Daniel P. Berrangé]

On Wed, Jan 30, 2019 at 11:14:27AM +0800, Jason Wang wrote:
> The tests tries to let qemu server mode to process the connection
> which turns out to be racy after commit 8258292e18c3 ("monitor: Remove
> "x-oob", offer capability "oob" unconditionally"). This is because the
> filter may try to mirror the packets before UNIX socket object is
> ready (connected was set to true) from the view of qemu. In this case
> the packet will be dropped silently.
> 
> Fixing this by passing pre-connected socket created by socketpair() to
> qemu through fd.
> 
> Cc: Peter Maydell <peter.maydell@linaro.org>
> Cc: Li Zhijian <lizhijian@cn.fujitsu.com>
> Cc: Peter Xu <peterx@redhat.com>
> Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
> Cc: Zhang Chen <zhangckid@gmail.com>
> Cc: Markus Armbruster <armbru@redhat.com>
> Cc: Daniel P. Berrange <berrange@redhat.com>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
> Changes from v1:
> - close the socket pairs in the end of test
> ---
>  tests/test-filter-mirror.c | 22 ++++++++++------------
>  1 file changed, 10 insertions(+), 12 deletions(-)

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>


Regards,
Daniel
-- 
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Re: [Qemu-devel] [PATCH V2] test-filter-mirror: pass UNIX domain socket through fd

[Zhang Chen]

On Wed, Jan 30, 2019 at 11:14 AM Jason Wang <jasowang@redhat.com> wrote:

> The tests tries to let qemu server mode to process the connection
> which turns out to be racy after commit 8258292e18c3 ("monitor: Remove
> "x-oob", offer capability "oob" unconditionally"). This is because the
> filter may try to mirror the packets before UNIX socket object is
> ready (connected was set to true) from the view of qemu. In this case
> the packet will be dropped silently.
>
> Fixing this by passing pre-connected socket created by socketpair() to
> qemu through fd.
>
> Cc: Peter Maydell <peter.maydell@linaro.org>
> Cc: Li Zhijian <lizhijian@cn.fujitsu.com>
> Cc: Peter Xu <peterx@redhat.com>
> Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
> Cc: Zhang Chen <zhangckid@gmail.com>
> Cc: Markus Armbruster <armbru@redhat.com>
> Cc: Daniel P. Berrange <berrange@redhat.com>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
>

Looks good for me.
Reviewed-by: Zhang Chen <zhangckid@gmail.com>

By the way: Do we need add ASCII diagram to explain data flow in this file
or commit log?

Thanks
Zhang Chen


> ---
> Changes from v1:
> - close the socket pairs in the end of test
> ---
>  tests/test-filter-mirror.c | 22 ++++++++++------------
>  1 file changed, 10 insertions(+), 12 deletions(-)
>
> diff --git a/tests/test-filter-mirror.c b/tests/test-filter-mirror.c
> index 7ab2aed8a0..d942c74a3f 100644
> --- a/tests/test-filter-mirror.c
> +++ b/tests/test-filter-mirror.c
> @@ -21,10 +21,9 @@
>
>  static void test_mirror(void)
>  {
> -    int send_sock[2], recv_sock;
> +    int send_sock[2], recv_sock[2];
>      uint32_t ret = 0, len = 0;
>      char send_buf[] = "Hello! filter-mirror~";
> -    char sock_path[] = "filter-mirror.XXXXXX";
>      char *recv_buf;
>      uint32_t size = sizeof(send_buf);
>      size = htonl(size);
> @@ -38,18 +37,15 @@ static void test_mirror(void)
>      ret = socketpair(PF_UNIX, SOCK_STREAM, 0, send_sock);
>      g_assert_cmpint(ret, !=, -1);
>
> -    ret = mkstemp(sock_path);
> +    ret = socketpair(PF_UNIX, SOCK_STREAM, 0, recv_sock);
>      g_assert_cmpint(ret, !=, -1);
>
>      qts = qtest_initf(
>          "-netdev socket,id=qtest-bn0,fd=%d "
>          "-device %s,netdev=qtest-bn0,id=qtest-e0 "
> -        "-chardev socket,id=mirror0,path=%s,server,nowait "
> +        "-chardev socket,id=mirror0,fd=%d "
>          "-object
> filter-mirror,id=qtest-f0,netdev=qtest-bn0,queue=tx,outdev=mirror0 "
> -        , send_sock[1], devstr, sock_path);
> -
> -    recv_sock = unix_connect(sock_path, NULL);
> -    g_assert_cmpint(recv_sock, !=, -1);
> +        , send_sock[1], devstr, recv_sock[1]);
>
>      struct iovec iov[] = {
>          {
> @@ -67,18 +63,20 @@ static void test_mirror(void)
>      g_assert_cmpint(ret, ==, sizeof(send_buf) + sizeof(size));
>      close(send_sock[0]);
>
> -    ret = qemu_recv(recv_sock, &len, sizeof(len), 0);
> +    ret = qemu_recv(recv_sock[0], &len, sizeof(len), 0);
>      g_assert_cmpint(ret, ==, sizeof(len));
>      len = ntohl(len);
>
>      g_assert_cmpint(len, ==, sizeof(send_buf));
>      recv_buf = g_malloc(len);
> -    ret = qemu_recv(recv_sock, recv_buf, len, 0);
> +    ret = qemu_recv(recv_sock[0], recv_buf, len, 0);
>      g_assert_cmpstr(recv_buf, ==, send_buf);
>
>      g_free(recv_buf);
> -    close(recv_sock);
> -    unlink(sock_path);
> +    close(send_sock[0]);
> +    close(send_sock[1]);
> +    close(recv_sock[0]);
> +    close(recv_sock[1]);
>      qtest_quit(qts);
>  }
>
> --
> 2.17.1
>
>

Re: [Qemu-devel] [PATCH V2] test-filter-mirror: pass UNIX domain socket through fd

[Peter Maydell]

On Wed, 30 Jan 2019 at 03:14, Jason Wang <jasowang@redhat.com> wrote:
>
> The tests tries to let qemu server mode to process the connection
> which turns out to be racy after commit 8258292e18c3 ("monitor: Remove
> "x-oob", offer capability "oob" unconditionally"). This is because the
> filter may try to mirror the packets before UNIX socket object is
> ready (connected was set to true) from the view of qemu. In this case
> the packet will be dropped silently.
>
> Fixing this by passing pre-connected socket created by socketpair() to
> qemu through fd.

Hi; assuming it passes my merge tests I'm planning to apply
this directly to master since it will make my merge testing
easier. Thanks for tracking down and fixing the bug!

-- PMM