Jay Elliott <jelliott@xxxxxxxxxx> wrote:
> On Sat, Nov 11, 2017 at 10:27 AM, Florian Westphal <fw@xxxxxxxxx> wrote:
> > It also looks wrong.
> > let ct->timeout be 1000.
> > let nfct_time_stamp be 0x80000000
> >
> > Then ct->timout is capped to 0x7fffffff.
> > Next check considers the timeout to be expired, as 0x7fff... - 0x800 < 0.
>
> Thanks for pointing that out; it does look like something that could
> cause troubles.
>
> Is it alright if I submit a fix to this as a separate patch? I
> *think* I have a solution (pending some testing), but I also think
> it's outside of the scope of this commit since it's a pre-existing
> problem so I'd like to fix it separately.
Sorry, I am not following. This problem is added with this patch.
> > So I guess best bet is to actually do a 64bit multiplication, as you
> > did, then truncate.
> >
> > Please use u64 for this (the u_intXX_t types are prehistoric leftovers).
>
> So to clarify, are changing the u_int64_t variables to u64 and fixing
> the case where nfct_time_stamp >= 0x8000... the only changes that need
> to be made based on the v2 patch I sent out?
Yes, I think so, only changes in nfnetlink.c are needed, i.e. (totally untested):
- u_int32_t timeout = ntohl(nla_get_be32(cda[CTA_TIMEOUT]));
+ u64 timeout = ntohl(nla_get_be32(cda[CTA_TIMEOUT])) * HZ;
+
+ if (timeout > INT_MAX)
timeout = INT_MAX;
- ct->timeout = nfct_time_stamp + timeout * HZ;
+ ct->timeout = nfct_time_stamp + (u32)timeout;
if (test_bit(IPS_DYING_BIT, &ct->status))
return -ETIME;
@@ -1762,6 +1765,8 @@ static int change_seq_adj(struct nf_ct_seqadj *seq,
int err = -EINVAL;
struct nf_conntrack_helper *helper;
struct nf_conn_tstamp *tstamp;
+ u64 timeout_nla;
ct = nf_conntrack_alloc(net, zone, otuple, rtuple, GFP_ATOMIC);
if (IS_ERR(ct))
@@ -1770,7 +1775,11 @@ static int change_seq_adj(struct nf_ct_seqadj *seq,
if (!cda[CTA_TIMEOUT])
goto err1;
- ct->timeout = nfct_time_stamp + ntohl(nla_get_be32(cda[CTA_TIMEOUT])) * HZ;
+ timeout_nla = ntohl(nla_get_be32(cda[CTA_TIMEOUT])) * HZ;
+ if (timeout_nla > INT_MAX)
+ timeout_nla = INT_MAX;
+ ct->timeout = nfct_time_stamp + timeout_nla;
--
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