| Message ID | 20201210151426.89244-1-alex.chen@huawei.com |
|---|---|
| State | New |
| Headers | show |
| Series | virtiofsd: Fix potential NULL pointer dereference in virtio_send_msg() | expand |
* Alex Chen (alex.chen@huawei.com) wrote: > The 'ch' will be NULL in the following stack: > send_notify_iov()->fuse_send_msg()->virtio_send_msg(), > so we should check 'ch' is valid before dereferencing it > > Reported-by: Euler Robot <euler.robot@huawei.com> > Signed-off-by: Alex Chen <alex.chen@huawei.com> Please check, but I don't think we can currently hit this because we never call send_notify_iov - it's currently called by fuse_lowlevel_notify_inval_entry, inval_inode, and fuse_lowlevel_notify_poll - but I don't think those are called anywhere. In that case, probably the best fix is to remove those until we put notify back in. Dave > --- > tools/virtiofsd/fuse_virtio.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c > index 623812c432..31b2187a15 100644 > --- a/tools/virtiofsd/fuse_virtio.c > +++ b/tools/virtiofsd/fuse_virtio.c > @@ -205,6 +205,8 @@ static void copy_iov(struct iovec *src_iov, int src_count, > int virtio_send_msg(struct fuse_session *se, struct fuse_chan *ch, > struct iovec *iov, int count) > { > + assert(ch); > + > FVRequest *req = container_of(ch, FVRequest, ch); > struct fv_QueueInfo *qi = ch->qi; > VuDev *dev = &se->virtio_dev->dev; > -- > 2.19.1 >
Hi Dave, On 2020/12/11 2:00, Dr. David Alan Gilbert wrote: > * Alex Chen (alex.chen@huawei.com) wrote: >> The 'ch' will be NULL in the following stack: >> send_notify_iov()->fuse_send_msg()->virtio_send_msg(), >> so we should check 'ch' is valid before dereferencing it >> >> Reported-by: Euler Robot <euler.robot@huawei.com> >> Signed-off-by: Alex Chen <alex.chen@huawei.com> > > Please check, but I don't think we can currently hit this because > we never call send_notify_iov - it's currently called by > fuse_lowlevel_notify_inval_entry, inval_inode, and > fuse_lowlevel_notify_poll - > but I don't think those are called anywhere. > Thanks for your review. The send_notify_iov() is really not being called. > In that case, probably the best fix is to remove those until we > put notify back in. > OK, I will remove those temporarily useless code and send patch v2 to fix this problem. Thanks, Alex > Dave > >> --- >> tools/virtiofsd/fuse_virtio.c | 2 ++ >> 1 file changed, 2 insertions(+) >> >> diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c >> index 623812c432..31b2187a15 100644 >> --- a/tools/virtiofsd/fuse_virtio.c >> +++ b/tools/virtiofsd/fuse_virtio.c >> @@ -205,6 +205,8 @@ static void copy_iov(struct iovec *src_iov, int src_count, >> int virtio_send_msg(struct fuse_session *se, struct fuse_chan *ch, >> struct iovec *iov, int count) >> { >> + assert(ch); >> + >> FVRequest *req = container_of(ch, FVRequest, ch); >> struct fv_QueueInfo *qi = ch->qi; >> VuDev *dev = &se->virtio_dev->dev; >> -- >> 2.19.1 >>
diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c index 623812c432..31b2187a15 100644 --- a/tools/virtiofsd/fuse_virtio.c +++ b/tools/virtiofsd/fuse_virtio.c @@ -205,6 +205,8 @@ static void copy_iov(struct iovec *src_iov, int src_count, int virtio_send_msg(struct fuse_session *se, struct fuse_chan *ch, struct iovec *iov, int count) { + assert(ch); + FVRequest *req = container_of(ch, FVRequest, ch); struct fv_QueueInfo *qi = ch->qi; VuDev *dev = &se->virtio_dev->dev;
The 'ch' will be NULL in the following stack: send_notify_iov()->fuse_send_msg()->virtio_send_msg(), so we should check 'ch' is valid before dereferencing it Reported-by: Euler Robot <euler.robot@huawei.com> Signed-off-by: Alex Chen <alex.chen@huawei.com> --- tools/virtiofsd/fuse_virtio.c | 2 ++ 1 file changed, 2 insertions(+)