| Message ID | 20110528003651.GA8380@redhat.com |
|---|---|
| State | Not Applicable, archived |
| Delegated to: | David Miller |
| Headers | show |
On Fri, May 27, 2011 at 08:36:51PM -0400, Dave Jones wrote: > > > Not catastrophic, but ipqueue seems to be too trusting of what it gets > > > passed from userspace, and passes it on down to the page allocator, > > > where it will spew warnings if the page order is too high. > > > > > > __ipq_rcv_skb has several checks for lengths too small, but doesn't > > > seem to have any for oversized ones. I'm not sure what the maximum > > > we should check for is. I'll code up a diff if anyone has any ideas > > > on a sane maximum. > > > > Maybe the thing to do is to simply pass __GFP_NOWARN to nlmsg_new() > > in netlink_ack()? > > > > Anyone else have a better idea? > > So I went back to this today, and found something that doesn't look right. > After adding some instrumentation, and re-running my tests, I found that > the reason we were blowing up with enormous allocations was that we > were passing down a nlmsglen's like -1061109568 > > Is there any reason for that to be signed ? > The nlmsg_len entry of nlmsghdr is a u32, so I'm assuming this is a bug. > > With the patch below, I haven't been able to reproduce the problem, but > I don't know if I've inadvertantly broken some other behaviour somewhere > deeper in netlink where this is valid. any feedback on this ? am I barking up the wrong tree ? Dave -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Dave Jones <davej@redhat.com> Date: Fri, 27 May 2011 20:36:51 -0400 > On Tue, Apr 19, 2011 at 08:41:05PM -0700, David Miller wrote: > > From: Dave Jones <davej@redhat.com> > > Date: Tue, 19 Apr 2011 21:42:22 -0400 > > > > > Not catastrophic, but ipqueue seems to be too trusting of what it gets > > > passed from userspace, and passes it on down to the page allocator, > > > where it will spew warnings if the page order is too high. > > > > > > __ipq_rcv_skb has several checks for lengths too small, but doesn't > > > seem to have any for oversized ones. I'm not sure what the maximum > > > we should check for is. I'll code up a diff if anyone has any ideas > > > on a sane maximum. > > > > Maybe the thing to do is to simply pass __GFP_NOWARN to nlmsg_new() > > in netlink_ack()? > > > > Anyone else have a better idea? > > So I went back to this today, and found something that doesn't look right. > After adding some instrumentation, and re-running my tests, I found that > the reason we were blowing up with enormous allocations was that we > were passing down a nlmsglen's like -1061109568 > > Is there any reason for that to be signed ? > The nlmsg_len entry of nlmsghdr is a u32, so I'm assuming this is a bug. > > With the patch below, I haven't been able to reproduce the problem, but > I don't know if I've inadvertantly broken some other behaviour somewhere > deeper in netlink where this is valid. netfilter-devel and maintainers CC:'d > -- > > Netlink message lengths can't be negative, so use unsigned variables. > > Signed-off-by: Dave Jones <davej@redhat.com> > > diff --git a/net/ipv4/netfilter/ip_queue.c b/net/ipv4/netfilter/ip_queue.c > index d2c1311..f7f9bd7 100644 > --- a/net/ipv4/netfilter/ip_queue.c > +++ b/net/ipv4/netfilter/ip_queue.c > @@ -402,7 +402,8 @@ ipq_dev_drop(int ifindex) > static inline void > __ipq_rcv_skb(struct sk_buff *skb) > { > - int status, type, pid, flags, nlmsglen, skblen; > + int status, type, pid, flags; > + unsigned int nlmsglen, skblen; > struct nlmsghdr *nlh; > > skblen = skb->len; > diff --git a/net/ipv6/netfilter/ip6_queue.c b/net/ipv6/netfilter/ip6_queue.c > index 413ab07..065fe40 100644 > --- a/net/ipv6/netfilter/ip6_queue.c > +++ b/net/ipv6/netfilter/ip6_queue.c > @@ -403,7 +403,8 @@ ipq_dev_drop(int ifindex) > static inline void > __ipq_rcv_skb(struct sk_buff *skb) > { > - int status, type, pid, flags, nlmsglen, skblen; > + int status, type, pid, flags; > + unsigned int nlmsglen, skblen; > struct nlmsghdr *nlh; > > skblen = skb->len; -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 28/05/11 02:36, Dave Jones wrote: > On Tue, Apr 19, 2011 at 08:41:05PM -0700, David Miller wrote: > > From: Dave Jones <davej@redhat.com> > > Date: Tue, 19 Apr 2011 21:42:22 -0400 > > > > > Not catastrophic, but ipqueue seems to be too trusting of what it gets > > > passed from userspace, and passes it on down to the page allocator, > > > where it will spew warnings if the page order is too high. > > > > > > __ipq_rcv_skb has several checks for lengths too small, but doesn't > > > seem to have any for oversized ones. I'm not sure what the maximum > > > we should check for is. I'll code up a diff if anyone has any ideas > > > on a sane maximum. > > > > Maybe the thing to do is to simply pass __GFP_NOWARN to nlmsg_new() > > in netlink_ack()? > > > > Anyone else have a better idea? > > So I went back to this today, and found something that doesn't look right. > After adding some instrumentation, and re-running my tests, I found that > the reason we were blowing up with enormous allocations was that we > were passing down a nlmsglen's like -1061109568 > > Is there any reason for that to be signed ? > The nlmsg_len entry of nlmsghdr is a u32, so I'm assuming this is a bug. > > With the patch below, I haven't been able to reproduce the problem, but > I don't know if I've inadvertantly broken some other behaviour somewhere > deeper in netlink where this is valid. I have applied this. Thanks. BTW, ip[6]_queue has been marked obsoleted since long time, probably we can schedule this for removal anytime soon. The nfnetlink_queue successor has been there to provide a replacement for this since long time. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/ipv4/netfilter/ip_queue.c b/net/ipv4/netfilter/ip_queue.c index d2c1311..f7f9bd7 100644 --- a/net/ipv4/netfilter/ip_queue.c +++ b/net/ipv4/netfilter/ip_queue.c @@ -402,7 +402,8 @@ ipq_dev_drop(int ifindex) static inline void __ipq_rcv_skb(struct sk_buff *skb) { - int status, type, pid, flags, nlmsglen, skblen; + int status, type, pid, flags; + unsigned int nlmsglen, skblen; struct nlmsghdr *nlh; skblen = skb->len; diff --git a/net/ipv6/netfilter/ip6_queue.c b/net/ipv6/netfilter/ip6_queue.c index 413ab07..065fe40 100644 --- a/net/ipv6/netfilter/ip6_queue.c +++ b/net/ipv6/netfilter/ip6_queue.c @@ -403,7 +403,8 @@ ipq_dev_drop(int ifindex) static inline void __ipq_rcv_skb(struct sk_buff *skb) { - int status, type, pid, flags, nlmsglen, skblen; + int status, type, pid, flags; + unsigned int nlmsglen, skblen; struct nlmsghdr *nlh; skblen = skb->len;