| Message ID | 20191017212734.10778-1-mchristi@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | nbd: verify socket is supported during setup | expand |
On Thu, Oct 17, 2019 at 04:27:34PM -0500, Mike Christie wrote: > nbd requires socket families to support the shutdown method so the nbd > recv workqueue can be woken up from its sock_recvmsg call. If the socket > does not support the callout we will leave recv works running or get hangs > later when the device or module is removed. > > This adds a check during socket connection/reconnection to make sure the > socket being passed in supports the needed callout. > > Reported-by: syzbot+24c12fa8d218ed26011a@syzkaller.appspotmail.com > Fixes: e9e006f5fcf2 ("nbd: fix max number of supported devs") > Signed-off-by: Mike Christie <mchristi@redhat.com> I tested this patch to try to make sure it doesn't break typical existing use cases of the kernel NBD client using Unix and TCP servers. I used a Fedora 30 virtual machine, nbdkit-1.12.8-1.fc30, and the upstream kernel + your patch for testing. I tested it using loop-style commands similar to what I did in this talk[1] using commands from the nbdkit manual[2]. Note I did *not* test the negative case, eg. NBD over a netlink socket, as I have no easy way to test that. Anyway, I can confirm that both Unix domain sockets and TCP to localhost works fine with this patch, so: Tested-by: Richard W.M. Jones <rjones@redhat.com> Rich. [1] https://archive.fosdem.org/2019/schedule/event/nbdkit/ [2] http://libguestfs.org/nbdkit-loop.1.html > --- > drivers/block/nbd.c | 23 +++++++++++++++++++++-- > 1 file changed, 21 insertions(+), 2 deletions(-) > > diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c > index 478aa86fc1f2..7bd9e92f6bb7 100644 > --- a/drivers/block/nbd.c > +++ b/drivers/block/nbd.c > @@ -972,6 +972,25 @@ static blk_status_t nbd_queue_rq(struct blk_mq_hw_ctx *hctx, > return ret; > } > > +static struct socket *nbd_get_socket(struct nbd_device *nbd, unsigned long fd, > + int *err) > +{ > + struct socket *sock; > + > + *err = 0; > + sock = sockfd_lookup(fd, err); > + if (!sock) > + return NULL; > + > + if (sock->ops->shutdown == sock_no_shutdown) { > + dev_err(disk_to_dev(nbd->disk), "Unsupported socket: shutdown callout must be supported.\n"); > + *err = -EINVAL; > + return NULL; > + } > + > + return sock; > +} > + > static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg, > bool netlink) > { > @@ -981,7 +1000,7 @@ static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg, > struct nbd_sock *nsock; > int err; > > - sock = sockfd_lookup(arg, &err); > + sock = nbd_get_socket(nbd, arg, &err); > if (!sock) > return err; > > @@ -1033,7 +1052,7 @@ static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg) > int i; > int err; > > - sock = sockfd_lookup(arg, &err); > + sock = nbd_get_socket(nbd, arg, &err); > if (!sock) > return err; > > -- > 2.20.1
On 10/17/19 3:27 PM, Mike Christie wrote: > nbd requires socket families to support the shutdown method so the nbd > recv workqueue can be woken up from its sock_recvmsg call. If the socket > does not support the callout we will leave recv works running or get hangs > later when the device or module is removed. > > This adds a check during socket connection/reconnection to make sure the > socket being passed in supports the needed callout. Applied, thanks Mike.
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 478aa86fc1f2..7bd9e92f6bb7 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -972,6 +972,25 @@ static blk_status_t nbd_queue_rq(struct blk_mq_hw_ctx *hctx, return ret; } +static struct socket *nbd_get_socket(struct nbd_device *nbd, unsigned long fd, + int *err) +{ + struct socket *sock; + + *err = 0; + sock = sockfd_lookup(fd, err); + if (!sock) + return NULL; + + if (sock->ops->shutdown == sock_no_shutdown) { + dev_err(disk_to_dev(nbd->disk), "Unsupported socket: shutdown callout must be supported.\n"); + *err = -EINVAL; + return NULL; + } + + return sock; +} + static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg, bool netlink) { @@ -981,7 +1000,7 @@ static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg, struct nbd_sock *nsock; int err; - sock = sockfd_lookup(arg, &err); + sock = nbd_get_socket(nbd, arg, &err); if (!sock) return err; @@ -1033,7 +1052,7 @@ static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg) int i; int err; - sock = sockfd_lookup(arg, &err); + sock = nbd_get_socket(nbd, arg, &err); if (!sock) return err;
nbd requires socket families to support the shutdown method so the nbd recv workqueue can be woken up from its sock_recvmsg call. If the socket does not support the callout we will leave recv works running or get hangs later when the device or module is removed. This adds a check during socket connection/reconnection to make sure the socket being passed in supports the needed callout. Reported-by: syzbot+24c12fa8d218ed26011a@syzkaller.appspotmail.com Fixes: e9e006f5fcf2 ("nbd: fix max number of supported devs") Signed-off-by: Mike Christie <mchristi@redhat.com> --- drivers/block/nbd.c | 23 +++++++++++++++++++++-- 1 file changed, 21 insertions(+), 2 deletions(-)