improve request header handling

We should require a non-empty payload for every command type except
VFIO_USER_DEVICE_RESET.

We should also reply to the caller with such failures.

Add some testing for is_valid_header(), and move the fd handling test over to it
too.

Signed-off-by: John Levon <john.levon@nutanix.com>
Reviewed-by: Thanos Makatos <thanos.makatos@nutanix.com>

3 files changed, 131 insertions, 1 deletions

diff --git a/test/py/libvfio_user.py b/test/py/libvfio_user.py
index a73c228..31e9767 100644
--- a/test/py/libvfio_user.py
+++ b/test/py/libvfio_user.py
@@ -442,7 +442,7 @@ def vfio_user_header(cmd, size, no_reply=False, error=False, error_no=0):
     global msg_id
 
     buf = struct.pack("HHIII", msg_id, cmd, SIZEOF_VFIO_USER_HEADER + size,
-                      0, error_no)
+                      VFIO_USER_F_TYPE_COMMAND, error_no)
 
     msg_id += 1
 
diff --git a/test/py/test_device_set_irqs.py b/test/py/test_device_set_irqs.py
index af3a03e..9e54381 100644
--- a/test/py/test_device_set_irqs.py
+++ b/test/py/test_device_set_irqs.py
@@ -59,6 +59,12 @@ def test_device_set_irqs_setup():
 
     sock = connect_client(ctx)
 
+def test_device_set_irqs_no_irq_set():
+    hdr = vfio_user_header(VFIO_USER_DEVICE_SET_IRQS, size=0)
+    sock.send(hdr)
+    vfu_run_ctx(ctx)
+    get_reply(sock, expect=errno.EINVAL)
+
 def test_device_set_irqs_short_write():
     payload = struct.pack("II", 0, 0)
 
diff --git a/test/py/test_request_errors.py b/test/py/test_request_errors.py
new file mode 100644
index 0000000..fe6f29e
--- /dev/null
+++ b/test/py/test_request_errors.py
@@ -0,0 +1,124 @@
+#
+# Copyright (c) 2021 Nutanix Inc. All rights reserved.
+#
+# Authors: John Levon <john.levon@nutanix.com>
+#
+#  Redistribution and use in source and binary forms, with or without
+#  modification, are permitted provided that the following conditions are met:
+#      * Redistributions of source code must retain the above copyright
+#        notice, this list of conditions and the following disclaimer.
+#      * Redistributions in binary form must reproduce the above copyright
+#        notice, this list of conditions and the following disclaimer in the
+#        documentation and/or other materials provided with the distribution.
+#      * Neither the name of Nutanix nor the names of its contributors may be
+#        used to endorse or promote products derived from this software without
+#        specific prior written permission.
+#
+#  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+#  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+#  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+#  ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
+#  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+#  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+#  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+#  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+#  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+#  OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
+#  DAMAGE.
+#
+
+from libvfio_user import *
+import ctypes as c
+import errno
+import os
+import sys
+
+ctx = None
+sock = None
+
+argsz = len(vfio_irq_set())
+
+def test_request_errors_setup():
+    global ctx, sock
+
+    ctx = vfu_create_ctx(flags=LIBVFIO_USER_FLAG_ATTACH_NB)
+    assert ctx != None
+
+    ret = vfu_pci_init(ctx)
+    assert ret == 0
+
+    ret = vfu_setup_device_nr_irqs(ctx, VFU_DEV_MSIX_IRQ, 2048)
+    assert ret == 0
+
+    ret = vfu_realize_ctx(ctx)
+    assert ret == 0
+
+    sock = connect_client(ctx)
+
+def test_too_small():
+    # struct vfio_user_header
+    hdr = struct.pack("HHIII", 0xbad1, VFIO_USER_DEVICE_SET_IRQS,
+                      SIZEOF_VFIO_USER_HEADER - 1, VFIO_USER_F_TYPE_COMMAND, 0)
+
+    sock.send(hdr)
+    vfu_run_ctx(ctx)
+    get_reply(sock, expect=errno.EINVAL)
+
+def test_too_large():
+    # struct vfio_user_header
+    hdr = struct.pack("HHIII", 0xbad1, VFIO_USER_DEVICE_SET_IRQS,
+                      SERVER_MAX_MSG_SIZE + 1, VFIO_USER_F_TYPE_COMMAND, 0)
+
+    sock.send(hdr)
+    vfu_run_ctx(ctx)
+    get_reply(sock, expect=errno.EINVAL)
+
+def test_unsolicited_reply():
+    # struct vfio_user_header
+    hdr = struct.pack("HHIII", 0xbad2, VFIO_USER_DEVICE_SET_IRQS,
+                      SIZEOF_VFIO_USER_HEADER, VFIO_USER_F_TYPE_REPLY, 0)
+
+    sock.send(hdr)
+    vfu_run_ctx(ctx)
+    get_reply(sock, expect=errno.EINVAL)
+
+def test_bad_command():
+    hdr = vfio_user_header(VFIO_USER_MAX, size=1)
+
+    sock.send(hdr + b'\0')
+    vfu_run_ctx(ctx)
+    get_reply(sock, expect=errno.EINVAL)
+
+def test_no_payload():
+    hdr = vfio_user_header(VFIO_USER_DEVICE_SET_IRQS, size=0)
+    sock.send(hdr)
+    vfu_run_ctx(ctx)
+    get_reply(sock, expect=errno.EINVAL)
+
+def test_bad_request_closes_fds():
+    payload = vfio_irq_set(argsz=argsz, flags=VFIO_IRQ_SET_ACTION_TRIGGER |
+                           VFIO_IRQ_SET_DATA_BOOL, index=VFU_DEV_MSIX_IRQ,
+                           start=0, count=1)
+
+    fd1 = eventfd()
+    fd2 = eventfd()
+
+    hdr = vfio_user_header(VFIO_USER_DEVICE_SET_IRQS, size=len(payload))
+    sock.sendmsg([hdr + payload], [(socket.SOL_SOCKET, socket.SCM_RIGHTS,
+                 struct.pack("II", fd1, fd2))])
+    vfu_run_ctx(ctx)
+    get_reply(sock, expect=errno.EINVAL)
+
+    #
+    # It's a little cheesy, but this is just ensuring no fd's remain open past
+    # the one we just allocated; i.e. free_msg() freed the fds it got.
+    #
+    test_fd = eventfd()
+    assert test_fd == fd2 + 1
+    os.close(test_fd)
+
+    os.close(fd1)
+    os.close(fd2)
+
+def test_request_errors_cleanup():
+    vfu_destroy_ctx(ctx)