Messages in this thread | | | Date | Wed, 18 Jul 2018 07:08:46 +0200 | From | Dominique Martinet <> | Subject | Re: [V9fs-developer] [PATCH] p9_parse_header() validate PDU length |
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Tomas Bortoli wrote on Thu, Jul 12, 2018: > + Cc: Andrew Morton <akpm@linux-foundation.org> > > On 07/12/2018 01:43 PM, Dominique Martinet wrote: > > Tomas Bortoli wrote on Thu, Jul 12, 2018: > >> This patch adds checks to the p9_parse_header() function to > >> verify that the length found within the header coincides with the actual > >> length of the PDU. Furthermore, it checks that the length stays within the > >> acceptable range. To do this the patch brings the actual length of the PDU > >> from the different transport layers (rdma and virtio). For TCP (trans_fd.c) > >> the length is not know before, so we get it from the header but we check it > >> anyway that it's within the valid range. > > Still for TCP it you could read "garbage" pre-allocated memory but I > don't know how much it is a risk, it might be a good idea to zero it > post allocation (I mean pdu->sdata). Allocated at: > > https://github.com/torvalds/linux/blob/master/net/9p/client.c#L236 > > > Just a note on transports here, I totally had forgotten about trans_xen > > when we discussed this earlier as it is fairly new, but it looks like it > > sets the length in the fcall properly so it should work without any > > change. > > > > I however cannot test trans=xen, so if someone could either point me to > > how to set that up (I couldn't find any decent documentation) or do some > > very basic tests that would be great. > > >> Signed-off-by: Tomas Bortoli <tomasbortoli@gmail.com> > >> Reported-by: syzbot+65c6b72f284a39d416b4@syzkaller.appspotmail.com > > Looks good to me, as the rdma/virtio part come from my suggestion: > > Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr> > > True > > > >> diff --git a/net/9p/trans_rdma.c b/net/9p/trans_rdma.c > >> index 3d414acb7015..002badbcc9c0 100644 > >> --- a/net/9p/trans_rdma.c > >> +++ b/net/9p/trans_rdma.c > >> @@ -319,7 +319,7 @@ recv_done(struct ib_cq *cq, struct ib_wc *wc) > >> > >> if (wc->status != IB_WC_SUCCESS) > >> goto err_out; > >> - > >> + c->rc->size = wc->byte_len; > > (nitpick, I'd keep the empty line here. If you don't mind I'll add it > > back in my tree; this doesn't warrant a v2) > > > > Sure, > > Tomas >
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