diff mbox

[v3,3/6] vhost-user: support receiving file descriptors in slave_read

Message ID 20180412151232.17506-4-tiwei.bie@intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Tiwei Bie April 12, 2018, 3:12 p.m. UTC
Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
---
 hw/virtio/vhost-user.c | 41 ++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 40 insertions(+), 1 deletion(-)

Comments

Michael S. Tsirkin May 23, 2018, 9:25 p.m. UTC | #1
On Thu, Apr 12, 2018 at 11:12:29PM +0800, Tiwei Bie wrote:
> Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>


Thinking about it, I think we should add a protocol
feature for this. This way remote can find out whether
it's safe to send this data to us.

> ---
>  hw/virtio/vhost-user.c | 41 ++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 40 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> index 91edd95453..9cea2c8c51 100644
> --- a/hw/virtio/vhost-user.c
> +++ b/hw/virtio/vhost-user.c
> @@ -854,14 +854,44 @@ static void slave_read(void *opaque)
>      VhostUserHeader hdr = { 0, };
>      VhostUserPayload payload = { 0, };
>      int size, ret = 0;
> +    struct iovec iov;
> +    struct msghdr msgh;
> +    int fd = -1;
> +    char control[CMSG_SPACE(sizeof(fd))];
> +    struct cmsghdr *cmsg;
> +    size_t fdsize;
> +
> +    memset(&msgh, 0, sizeof(msgh));
> +    msgh.msg_iov = &iov;
> +    msgh.msg_iovlen = 1;
> +    msgh.msg_control = control;
> +    msgh.msg_controllen = sizeof(control);
>  
>      /* Read header */
> -    size = read(u->slave_fd, &hdr, VHOST_USER_HDR_SIZE);
> +    iov.iov_base = &hdr;
> +    iov.iov_len = VHOST_USER_HDR_SIZE;
> +
> +    size = recvmsg(u->slave_fd, &msgh, 0);
>      if (size != VHOST_USER_HDR_SIZE) {
>          error_report("Failed to read from slave.");
>          goto err;
>      }
>  
> +    if (msgh.msg_flags & MSG_CTRUNC) {
> +        error_report("Truncated message.");
> +        goto err;
> +    }
> +
> +    for (cmsg = CMSG_FIRSTHDR(&msgh); cmsg != NULL;
> +         cmsg = CMSG_NXTHDR(&msgh, cmsg)) {
> +            if (cmsg->cmsg_level == SOL_SOCKET &&
> +                cmsg->cmsg_type == SCM_RIGHTS) {
> +                    fdsize = cmsg->cmsg_len - CMSG_LEN(0);
> +                    memcpy(&fd, CMSG_DATA(cmsg), fdsize);
> +                    break;
> +            }
> +    }
> +
>      if (hdr.size > VHOST_USER_PAYLOAD_SIZE) {
>          error_report("Failed to read msg header."
>                  " Size %d exceeds the maximum %zu.", hdr.size,
> @@ -885,9 +915,15 @@ static void slave_read(void *opaque)
>          break;
>      default:
>          error_report("Received unexpected msg type.");
> +        if (fd != -1) {
> +            close(fd);
> +        }
>          ret = -EINVAL;
>      }
>  
> +    /* Message handlers need to make sure that fd will be consumed. */
> +    fd = -1;
> +
>      /*
>       * REPLY_ACK feature handling. Other reply types has to be managed
>       * directly in their request handlers.
> @@ -920,6 +956,9 @@ err:
>      qemu_set_fd_handler(u->slave_fd, NULL, NULL, NULL);
>      close(u->slave_fd);
>      u->slave_fd = -1;
> +    if (fd != -1) {
> +        close(fd);
> +    }
>      return;
>  }
>  
> -- 
> 2.11.0
Tiwei Bie May 23, 2018, 11:12 p.m. UTC | #2
On Thu, May 24, 2018 at 12:25:23AM +0300, Michael S. Tsirkin wrote:
> On Thu, Apr 12, 2018 at 11:12:29PM +0800, Tiwei Bie wrote:
> > Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
> 
> 
> Thinking about it, I think we should add a protocol
> feature for this. This way remote can find out whether
> it's safe to send this data to us.

Okay, I can add a protocol feature for this.
Do you think it's OK to keep this patch as is
(this patch just extends slave_read() to support
receiving file descriptors) and introduce the
new protocol feature in a new patch to allow
backends to send file descriptors?

Best regards,
Tiwei Bie

> 
> > ---
> >  hw/virtio/vhost-user.c | 41 ++++++++++++++++++++++++++++++++++++++++-
> >  1 file changed, 40 insertions(+), 1 deletion(-)
> > 
> > diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> > index 91edd95453..9cea2c8c51 100644
> > --- a/hw/virtio/vhost-user.c
> > +++ b/hw/virtio/vhost-user.c
> > @@ -854,14 +854,44 @@ static void slave_read(void *opaque)
> >      VhostUserHeader hdr = { 0, };
> >      VhostUserPayload payload = { 0, };
> >      int size, ret = 0;
> > +    struct iovec iov;
> > +    struct msghdr msgh;
> > +    int fd = -1;
> > +    char control[CMSG_SPACE(sizeof(fd))];
> > +    struct cmsghdr *cmsg;
> > +    size_t fdsize;
> > +
> > +    memset(&msgh, 0, sizeof(msgh));
> > +    msgh.msg_iov = &iov;
> > +    msgh.msg_iovlen = 1;
> > +    msgh.msg_control = control;
> > +    msgh.msg_controllen = sizeof(control);
> >  
> >      /* Read header */
> > -    size = read(u->slave_fd, &hdr, VHOST_USER_HDR_SIZE);
> > +    iov.iov_base = &hdr;
> > +    iov.iov_len = VHOST_USER_HDR_SIZE;
> > +
> > +    size = recvmsg(u->slave_fd, &msgh, 0);
> >      if (size != VHOST_USER_HDR_SIZE) {
> >          error_report("Failed to read from slave.");
> >          goto err;
> >      }
> >  
> > +    if (msgh.msg_flags & MSG_CTRUNC) {
> > +        error_report("Truncated message.");
> > +        goto err;
> > +    }
> > +
> > +    for (cmsg = CMSG_FIRSTHDR(&msgh); cmsg != NULL;
> > +         cmsg = CMSG_NXTHDR(&msgh, cmsg)) {
> > +            if (cmsg->cmsg_level == SOL_SOCKET &&
> > +                cmsg->cmsg_type == SCM_RIGHTS) {
> > +                    fdsize = cmsg->cmsg_len - CMSG_LEN(0);
> > +                    memcpy(&fd, CMSG_DATA(cmsg), fdsize);
> > +                    break;
> > +            }
> > +    }
> > +
> >      if (hdr.size > VHOST_USER_PAYLOAD_SIZE) {
> >          error_report("Failed to read msg header."
> >                  " Size %d exceeds the maximum %zu.", hdr.size,
> > @@ -885,9 +915,15 @@ static void slave_read(void *opaque)
> >          break;
> >      default:
> >          error_report("Received unexpected msg type.");
> > +        if (fd != -1) {
> > +            close(fd);
> > +        }
> >          ret = -EINVAL;
> >      }
> >  
> > +    /* Message handlers need to make sure that fd will be consumed. */
> > +    fd = -1;
> > +
> >      /*
> >       * REPLY_ACK feature handling. Other reply types has to be managed
> >       * directly in their request handlers.
> > @@ -920,6 +956,9 @@ err:
> >      qemu_set_fd_handler(u->slave_fd, NULL, NULL, NULL);
> >      close(u->slave_fd);
> >      u->slave_fd = -1;
> > +    if (fd != -1) {
> > +        close(fd);
> > +    }
> >      return;
> >  }
> >  
> > -- 
> > 2.11.0
> 
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org
> For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org
>
Michael S. Tsirkin May 24, 2018, 1:48 p.m. UTC | #3
On Thu, May 24, 2018 at 07:12:15AM +0800, Tiwei Bie wrote:
> On Thu, May 24, 2018 at 12:25:23AM +0300, Michael S. Tsirkin wrote:
> > On Thu, Apr 12, 2018 at 11:12:29PM +0800, Tiwei Bie wrote:
> > > Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
> > 
> > 
> > Thinking about it, I think we should add a protocol
> > feature for this. This way remote can find out whether
> > it's safe to send this data to us.
> 
> Okay, I can add a protocol feature for this.
> Do you think it's OK to keep this patch as is
> (this patch just extends slave_read() to support
> receiving file descriptors) and introduce the
> new protocol feature in a new patch to allow
> backends to send file descriptors?
> 
> Best regards,
> Tiwei Bie

I already merged patch as is, we can add a patch on top that limits this
to a protocol feature.

> > 
> > > ---
> > >  hw/virtio/vhost-user.c | 41 ++++++++++++++++++++++++++++++++++++++++-
> > >  1 file changed, 40 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> > > index 91edd95453..9cea2c8c51 100644
> > > --- a/hw/virtio/vhost-user.c
> > > +++ b/hw/virtio/vhost-user.c
> > > @@ -854,14 +854,44 @@ static void slave_read(void *opaque)
> > >      VhostUserHeader hdr = { 0, };
> > >      VhostUserPayload payload = { 0, };
> > >      int size, ret = 0;
> > > +    struct iovec iov;
> > > +    struct msghdr msgh;
> > > +    int fd = -1;
> > > +    char control[CMSG_SPACE(sizeof(fd))];
> > > +    struct cmsghdr *cmsg;
> > > +    size_t fdsize;
> > > +
> > > +    memset(&msgh, 0, sizeof(msgh));
> > > +    msgh.msg_iov = &iov;
> > > +    msgh.msg_iovlen = 1;
> > > +    msgh.msg_control = control;
> > > +    msgh.msg_controllen = sizeof(control);
> > >  
> > >      /* Read header */
> > > -    size = read(u->slave_fd, &hdr, VHOST_USER_HDR_SIZE);
> > > +    iov.iov_base = &hdr;
> > > +    iov.iov_len = VHOST_USER_HDR_SIZE;
> > > +
> > > +    size = recvmsg(u->slave_fd, &msgh, 0);
> > >      if (size != VHOST_USER_HDR_SIZE) {
> > >          error_report("Failed to read from slave.");
> > >          goto err;
> > >      }
> > >  
> > > +    if (msgh.msg_flags & MSG_CTRUNC) {
> > > +        error_report("Truncated message.");
> > > +        goto err;
> > > +    }
> > > +
> > > +    for (cmsg = CMSG_FIRSTHDR(&msgh); cmsg != NULL;
> > > +         cmsg = CMSG_NXTHDR(&msgh, cmsg)) {
> > > +            if (cmsg->cmsg_level == SOL_SOCKET &&
> > > +                cmsg->cmsg_type == SCM_RIGHTS) {
> > > +                    fdsize = cmsg->cmsg_len - CMSG_LEN(0);
> > > +                    memcpy(&fd, CMSG_DATA(cmsg), fdsize);
> > > +                    break;
> > > +            }
> > > +    }
> > > +
> > >      if (hdr.size > VHOST_USER_PAYLOAD_SIZE) {
> > >          error_report("Failed to read msg header."
> > >                  " Size %d exceeds the maximum %zu.", hdr.size,
> > > @@ -885,9 +915,15 @@ static void slave_read(void *opaque)
> > >          break;
> > >      default:
> > >          error_report("Received unexpected msg type.");
> > > +        if (fd != -1) {
> > > +            close(fd);
> > > +        }
> > >          ret = -EINVAL;
> > >      }
> > >  
> > > +    /* Message handlers need to make sure that fd will be consumed. */
> > > +    fd = -1;
> > > +
> > >      /*
> > >       * REPLY_ACK feature handling. Other reply types has to be managed
> > >       * directly in their request handlers.
> > > @@ -920,6 +956,9 @@ err:
> > >      qemu_set_fd_handler(u->slave_fd, NULL, NULL, NULL);
> > >      close(u->slave_fd);
> > >      u->slave_fd = -1;
> > > +    if (fd != -1) {
> > > +        close(fd);
> > > +    }
> > >      return;
> > >  }
> > >  
> > > -- 
> > > 2.11.0
> > 
> > ---------------------------------------------------------------------
> > To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org
> > For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org
> >
Tiwei Bie May 24, 2018, 2:56 p.m. UTC | #4
On Thu, May 24, 2018 at 04:48:09PM +0300, Michael S. Tsirkin wrote:
> On Thu, May 24, 2018 at 07:12:15AM +0800, Tiwei Bie wrote:
> > On Thu, May 24, 2018 at 12:25:23AM +0300, Michael S. Tsirkin wrote:
> > > On Thu, Apr 12, 2018 at 11:12:29PM +0800, Tiwei Bie wrote:
> > > > Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
> > > 
> > > 
> > > Thinking about it, I think we should add a protocol
> > > feature for this. This way remote can find out whether
> > > it's safe to send this data to us.
> > 
> > Okay, I can add a protocol feature for this.
> > Do you think it's OK to keep this patch as is
> > (this patch just extends slave_read() to support
> > receiving file descriptors) and introduce the
> > new protocol feature in a new patch to allow
> > backends to send file descriptors?
> > 
> > Best regards,
> > Tiwei Bie
> 
> I already merged patch as is, we can add a patch on top that limits this
> to a protocol feature.

Got it. Thanks a lot!

Best regards,
Tiwei Bie

> 
> > > 
> > > > ---
> > > >  hw/virtio/vhost-user.c | 41 ++++++++++++++++++++++++++++++++++++++++-
> > > >  1 file changed, 40 insertions(+), 1 deletion(-)
> > > > 
> > > > diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> > > > index 91edd95453..9cea2c8c51 100644
> > > > --- a/hw/virtio/vhost-user.c
> > > > +++ b/hw/virtio/vhost-user.c
> > > > @@ -854,14 +854,44 @@ static void slave_read(void *opaque)
> > > >      VhostUserHeader hdr = { 0, };
> > > >      VhostUserPayload payload = { 0, };
> > > >      int size, ret = 0;
> > > > +    struct iovec iov;
> > > > +    struct msghdr msgh;
> > > > +    int fd = -1;
> > > > +    char control[CMSG_SPACE(sizeof(fd))];
> > > > +    struct cmsghdr *cmsg;
> > > > +    size_t fdsize;
> > > > +
> > > > +    memset(&msgh, 0, sizeof(msgh));
> > > > +    msgh.msg_iov = &iov;
> > > > +    msgh.msg_iovlen = 1;
> > > > +    msgh.msg_control = control;
> > > > +    msgh.msg_controllen = sizeof(control);
> > > >  
> > > >      /* Read header */
> > > > -    size = read(u->slave_fd, &hdr, VHOST_USER_HDR_SIZE);
> > > > +    iov.iov_base = &hdr;
> > > > +    iov.iov_len = VHOST_USER_HDR_SIZE;
> > > > +
> > > > +    size = recvmsg(u->slave_fd, &msgh, 0);
> > > >      if (size != VHOST_USER_HDR_SIZE) {
> > > >          error_report("Failed to read from slave.");
> > > >          goto err;
> > > >      }
> > > >  
> > > > +    if (msgh.msg_flags & MSG_CTRUNC) {
> > > > +        error_report("Truncated message.");
> > > > +        goto err;
> > > > +    }
> > > > +
> > > > +    for (cmsg = CMSG_FIRSTHDR(&msgh); cmsg != NULL;
> > > > +         cmsg = CMSG_NXTHDR(&msgh, cmsg)) {
> > > > +            if (cmsg->cmsg_level == SOL_SOCKET &&
> > > > +                cmsg->cmsg_type == SCM_RIGHTS) {
> > > > +                    fdsize = cmsg->cmsg_len - CMSG_LEN(0);
> > > > +                    memcpy(&fd, CMSG_DATA(cmsg), fdsize);
> > > > +                    break;
> > > > +            }
> > > > +    }
> > > > +
> > > >      if (hdr.size > VHOST_USER_PAYLOAD_SIZE) {
> > > >          error_report("Failed to read msg header."
> > > >                  " Size %d exceeds the maximum %zu.", hdr.size,
> > > > @@ -885,9 +915,15 @@ static void slave_read(void *opaque)
> > > >          break;
> > > >      default:
> > > >          error_report("Received unexpected msg type.");
> > > > +        if (fd != -1) {
> > > > +            close(fd);
> > > > +        }
> > > >          ret = -EINVAL;
> > > >      }
> > > >  
> > > > +    /* Message handlers need to make sure that fd will be consumed. */
> > > > +    fd = -1;
> > > > +
> > > >      /*
> > > >       * REPLY_ACK feature handling. Other reply types has to be managed
> > > >       * directly in their request handlers.
> > > > @@ -920,6 +956,9 @@ err:
> > > >      qemu_set_fd_handler(u->slave_fd, NULL, NULL, NULL);
> > > >      close(u->slave_fd);
> > > >      u->slave_fd = -1;
> > > > +    if (fd != -1) {
> > > > +        close(fd);
> > > > +    }
> > > >      return;
> > > >  }
> > > >  
> > > > -- 
> > > > 2.11.0
> > > 
> > > ---------------------------------------------------------------------
> > > To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org
> > > For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org
> > >
diff mbox

Patch

diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index 91edd95453..9cea2c8c51 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -854,14 +854,44 @@  static void slave_read(void *opaque)
     VhostUserHeader hdr = { 0, };
     VhostUserPayload payload = { 0, };
     int size, ret = 0;
+    struct iovec iov;
+    struct msghdr msgh;
+    int fd = -1;
+    char control[CMSG_SPACE(sizeof(fd))];
+    struct cmsghdr *cmsg;
+    size_t fdsize;
+
+    memset(&msgh, 0, sizeof(msgh));
+    msgh.msg_iov = &iov;
+    msgh.msg_iovlen = 1;
+    msgh.msg_control = control;
+    msgh.msg_controllen = sizeof(control);
 
     /* Read header */
-    size = read(u->slave_fd, &hdr, VHOST_USER_HDR_SIZE);
+    iov.iov_base = &hdr;
+    iov.iov_len = VHOST_USER_HDR_SIZE;
+
+    size = recvmsg(u->slave_fd, &msgh, 0);
     if (size != VHOST_USER_HDR_SIZE) {
         error_report("Failed to read from slave.");
         goto err;
     }
 
+    if (msgh.msg_flags & MSG_CTRUNC) {
+        error_report("Truncated message.");
+        goto err;
+    }
+
+    for (cmsg = CMSG_FIRSTHDR(&msgh); cmsg != NULL;
+         cmsg = CMSG_NXTHDR(&msgh, cmsg)) {
+            if (cmsg->cmsg_level == SOL_SOCKET &&
+                cmsg->cmsg_type == SCM_RIGHTS) {
+                    fdsize = cmsg->cmsg_len - CMSG_LEN(0);
+                    memcpy(&fd, CMSG_DATA(cmsg), fdsize);
+                    break;
+            }
+    }
+
     if (hdr.size > VHOST_USER_PAYLOAD_SIZE) {
         error_report("Failed to read msg header."
                 " Size %d exceeds the maximum %zu.", hdr.size,
@@ -885,9 +915,15 @@  static void slave_read(void *opaque)
         break;
     default:
         error_report("Received unexpected msg type.");
+        if (fd != -1) {
+            close(fd);
+        }
         ret = -EINVAL;
     }
 
+    /* Message handlers need to make sure that fd will be consumed. */
+    fd = -1;
+
     /*
      * REPLY_ACK feature handling. Other reply types has to be managed
      * directly in their request handlers.
@@ -920,6 +956,9 @@  err:
     qemu_set_fd_handler(u->slave_fd, NULL, NULL, NULL);
     close(u->slave_fd);
     u->slave_fd = -1;
+    if (fd != -1) {
+        close(fd);
+    }
     return;
 }