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Groups > linux.kernel > #1632045
| From | Sabrina Dubroca <sd@queasysnail.net> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v6 1/5] skbuff: return -EMSGSIZE in skb_to_sgvec to prevent overflow |
| Date | 2017-04-27 13:40 +0200 |
| Message-ID | <tAPWa-8ku-19@gated-at.bofh.it> (permalink) |
| References | <tAb2F-6Ff-25@gated-at.bofh.it> <tAdHb-8nI-5@gated-at.bofh.it> <tANUm-6Xr-21@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
2017-04-27, 11:21:51 +0200, Jason A. Donenfeld wrote:
> However, perhaps there's the chance that fraglist skbs having
> separate fraglists are actually forbidden? Is this the case?
Hmm, I think this can actually happen:
/* net/ipv4/ip_fragment.c */
static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev,
struct net_device *dev)
{
...
/* If the first fragment is fragmented itself, we split
* it to two chunks: the first with data and paged part
* and the second, holding only fragments. */
if (skb_has_frag_list(head)) {
struct sk_buff *clone;
int i, plen = 0;
clone = alloc_skb(0, GFP_ATOMIC);
if (!clone)
goto out_nomem;
clone->next = head->next;
head->next = clone;
skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
skb_frag_list_init(head);
for (i = 0; i < skb_shinfo(head)->nr_frags; i++)
plen += skb_frag_size(&skb_shinfo(head)->frags[i]);
clone->len = clone->data_len = head->data_len - plen;
head->data_len -= clone->len;
head->len -= clone->len;
clone->csum = 0;
clone->ip_summed = head->ip_summed;
add_frag_mem_limit(qp->q.net, clone->truesize);
}
...
}
You can test that with a vxlan tunnel on top of a vxlan tunnel ("real"
MTU is 1500, first tunnel MTU set to 10000, second tunnel MTU set to
40000 -- or anything, as long as they both get fragmented).
--
Sabrina
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[PATCH 1/5] skbuff: return -EMSGSIZE in skb_to_sgvec to prevent overflow "Jason A. Donenfeld" <Jason@zx2c4.com> - 2017-04-25 16:10 +0200
[PATCH v2 1/5] skbuff: return -EMSGSIZE in skb_to_sgvec to prevent overflow "Jason A. Donenfeld" <Jason@zx2c4.com> - 2017-04-25 16:20 +0200
[PATCH v3 1/5] skbuff: return -EMSGSIZE in skb_to_sgvec to prevent overflow "Jason A. Donenfeld" <Jason@zx2c4.com> - 2017-04-25 16:30 +0200
[PATCH 2/5] ipsec: check return value of skb_to_sgvec always "Jason A. Donenfeld" <Jason@zx2c4.com> - 2017-04-25 16:20 +0200
[PATCH 4/5] macsec: check return value of skb_to_sgvec always "Jason A. Donenfeld" <Jason@zx2c4.com> - 2017-04-25 16:20 +0200
Re: [PATCH 1/5] skbuff: return -EMSGSIZE in skb_to_sgvec to prevent overflow David Miller <davem@davemloft.net> - 2017-04-25 16:50 +0200
[PATCH v4 1/5] skbuff: return -EMSGSIZE in skb_to_sgvec to prevent overflow "Jason A. Donenfeld" <Jason@zx2c4.com> - 2017-04-25 17:10 +0200
Re: [PATCH v4 1/5] skbuff: return -EMSGSIZE in skb_to_sgvec to prevent overflow David Miller <davem@davemloft.net> - 2017-04-25 17:20 +0200
[PATCH v5 1/5] skbuff: return -EMSGSIZE in skb_to_sgvec to prevent overflow "Jason A. Donenfeld" <Jason@zx2c4.com> - 2017-04-25 18:00 +0200
[PATCH v5 3/5] rxrpc: check return value of skb_to_sgvec always "Jason A. Donenfeld" <Jason@zx2c4.com> - 2017-04-25 18:00 +0200
[PATCH v5 4/5] macsec: check return value of skb_to_sgvec always "Jason A. Donenfeld" <Jason@zx2c4.com> - 2017-04-25 18:00 +0200
[PATCH v5 2/5] ipsec: check return value of skb_to_sgvec always "Jason A. Donenfeld" <Jason@zx2c4.com> - 2017-04-25 18:00 +0200
[PATCH v5 5/5] virtio_net: check return value of skb_to_sgvec always "Jason A. Donenfeld" <Jason@zx2c4.com> - 2017-04-25 18:00 +0200
[PATCH v6 2/5] ipsec: check return value of skb_to_sgvec always "Jason A. Donenfeld" <Jason@zx2c4.com> - 2017-04-25 20:50 +0200
[PATCH v6 4/5] macsec: check return value of skb_to_sgvec always "Jason A. Donenfeld" <Jason@zx2c4.com> - 2017-04-25 20:50 +0200
[PATCH v6 5/5] virtio_net: check return value of skb_to_sgvec always "Jason A. Donenfeld" <Jason@zx2c4.com> - 2017-04-25 20:50 +0200
[PATCH v6 1/5] skbuff: return -EMSGSIZE in skb_to_sgvec to prevent overflow "Jason A. Donenfeld" <Jason@zx2c4.com> - 2017-04-25 20:50 +0200
[PATCH v6 3/5] rxrpc: check return value of skb_to_sgvec always "Jason A. Donenfeld" <Jason@zx2c4.com> - 2017-04-25 20:50 +0200
Re: [PATCH v6 3/5] rxrpc: check return value of skb_to_sgvec always Sabrina Dubroca <sd@queasysnail.net> - 2017-04-28 13:50 +0200
Re: [PATCH v6 3/5] rxrpc: check return value of skb_to_sgvec always "Jason A. Donenfeld" <Jason@zx2c4.com> - 2017-04-28 15:40 +0200
Re: [PATCH v6 1/5] skbuff: return -EMSGSIZE in skb_to_sgvec to prevent overflow "Jason A. Donenfeld" <Jason@zx2c4.com> - 2017-04-27 11:30 +0200
Re: [PATCH v6 1/5] skbuff: return -EMSGSIZE in skb_to_sgvec to prevent overflow Sabrina Dubroca <sd@queasysnail.net> - 2017-04-27 13:40 +0200
Re: [PATCH v6 1/5] skbuff: return -EMSGSIZE in skb_to_sgvec to prevent overflow "Jason A. Donenfeld" <Jason@zx2c4.com> - 2017-04-27 14:10 +0200
RE: [PATCH v6 1/5] skbuff: return -EMSGSIZE in skb_to_sgvec to prevent overflow David Laight <David.Laight@ACULAB.COM> - 2017-04-27 17:00 +0200
Re: [PATCH v6 1/5] skbuff: return -EMSGSIZE in skb_to_sgvec to prevent overflow David Miller <davem@davemloft.net> - 2017-04-27 18:00 +0200
Re: [PATCH v6 1/5] skbuff: return -EMSGSIZE in skb_to_sgvec to prevent overflow Sabrina Dubroca <sd@queasysnail.net> - 2017-04-28 18:20 +0200
Re: [PATCH v6 1/5] skbuff: return -EMSGSIZE in skb_to_sgvec to prevent overflow "Jason A. Donenfeld" <Jason@zx2c4.com> - 2017-04-29 00:50 +0200
Re: [PATCH 1/5] skbuff: return -EMSGSIZE in skb_to_sgvec to prevent overflow Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> - 2017-04-25 17:50 +0200
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