From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Eric Dumazet <edumazet@google.com>,
"David S. Miller" <davem@davemloft.net>,
Ben Hutchings <ben.hutchings@codethink.co.uk>
Subject: [PATCH 4.4 16/34] inet: frags: do not clone skb in ip_expire()
Date: Thu, 7 Feb 2019 12:41:58 +0100 [thread overview]
Message-ID: <20190207113026.216027585@linuxfoundation.org> (raw)
In-Reply-To: <20190207113025.552605181@linuxfoundation.org>
4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@google.com>
commit 1eec5d5670084ee644597bd26c25e22c69b9f748 upstream.
An skb_clone() was added in commit ec4fbd64751d ("inet: frag: release
spinlock before calling icmp_send()")
While fixing the bug at that time, it also added a very high cost
for DDOS frags, as the ICMP rate limit is applied after this
expensive operation (skb_clone() + consume_skb(), implying memory
allocations, copy, and freeing)
We can use skb_get(head) here, all we want is to make sure skb wont
be freed by another cpu.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/ipv4/ip_fragment.c | 16 ++++++----------
1 file changed, 6 insertions(+), 10 deletions(-)
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -143,8 +143,8 @@ static bool frag_expire_skip_icmp(u32 us
*/
static void ip_expire(unsigned long arg)
{
- struct sk_buff *clone, *head;
const struct iphdr *iph;
+ struct sk_buff *head;
struct net *net;
struct ipq *qp;
int err;
@@ -187,16 +187,12 @@ static void ip_expire(unsigned long arg)
(skb_rtable(head)->rt_type != RTN_LOCAL))
goto out;
- clone = skb_clone(head, GFP_ATOMIC);
+ skb_get(head);
+ spin_unlock(&qp->q.lock);
+ icmp_send(head, ICMP_TIME_EXCEEDED, ICMP_EXC_FRAGTIME, 0);
+ kfree_skb(head);
+ goto out_rcu_unlock;
- /* Send an ICMP "Fragment Reassembly Timeout" message. */
- if (clone) {
- spin_unlock(&qp->q.lock);
- icmp_send(clone, ICMP_TIME_EXCEEDED,
- ICMP_EXC_FRAGTIME, 0);
- consume_skb(clone);
- goto out_rcu_unlock;
- }
out:
spin_unlock(&qp->q.lock);
out_rcu_unlock:
next prev parent reply other threads:[~2019-02-07 11:43 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-07 11:41 [PATCH 4.4 00/34] 4.4.174-stable review Greg Kroah-Hartman
2019-02-07 11:41 ` [PATCH 4.4 01/34] inet: frags: change inet_frags_init_net() return value Greg Kroah-Hartman
2019-02-07 11:41 ` [PATCH 4.4 02/34] inet: frags: add a pointer to struct netns_frags Greg Kroah-Hartman
2019-02-07 11:41 ` [PATCH 4.4 03/34] inet: frags: refactor ipfrag_init() Greg Kroah-Hartman
2019-02-07 11:41 ` [PATCH 4.4 04/34] inet: frags: refactor ipv6_frag_init() Greg Kroah-Hartman
2019-02-07 11:41 ` [PATCH 4.4 05/34] inet: frags: refactor lowpan_net_frag_init() Greg Kroah-Hartman
2019-02-07 11:41 ` [PATCH 4.4 06/34] rhashtable: add rhashtable_lookup_get_insert_key() Greg Kroah-Hartman
2019-02-07 11:41 ` [PATCH 4.4 07/34] rhashtable: Add rhashtable_lookup() Greg Kroah-Hartman
2019-02-07 11:41 ` [PATCH 4.4 08/34] rhashtable: add schedule points Greg Kroah-Hartman
2019-02-07 11:41 ` [PATCH 4.4 09/34] inet: frags: use rhashtables for reassembly units Greg Kroah-Hartman
2019-02-07 11:41 ` [PATCH 4.4 10/34] net: ieee802154: 6lowpan: fix frag reassembly Greg Kroah-Hartman
2019-02-07 11:41 ` [PATCH 4.4 11/34] ipfrag: really prevent allocation on netns exit Greg Kroah-Hartman
2019-02-07 11:41 ` [PATCH 4.4 12/34] inet: frags: remove some helpers Greg Kroah-Hartman
2019-02-07 11:41 ` [PATCH 4.4 13/34] inet: frags: get rif of inet_frag_evicting() Greg Kroah-Hartman
2019-02-07 11:41 ` [PATCH 4.4 14/34] inet: frags: remove inet_frag_maybe_warn_overflow() Greg Kroah-Hartman
2019-02-07 11:41 ` [PATCH 4.4 15/34] inet: frags: break the 2GB limit for frags storage Greg Kroah-Hartman
2019-02-07 11:41 ` Greg Kroah-Hartman [this message]
2019-02-07 11:41 ` [PATCH 4.4 17/34] ipv6: frags: rewrite ip6_expire_frag_queue() Greg Kroah-Hartman
2019-02-07 11:42 ` [PATCH 4.4 18/34] rhashtable: reorganize struct rhashtable layout Greg Kroah-Hartman
2019-02-07 11:42 ` [PATCH 4.4 19/34] inet: frags: reorganize struct netns_frags Greg Kroah-Hartman
2019-02-07 11:42 ` [PATCH 4.4 20/34] inet: frags: get rid of ipfrag_skb_cb/FRAG_CB Greg Kroah-Hartman
2019-02-07 11:42 ` [PATCH 4.4 21/34] inet: frags: fix ip6frag_low_thresh boundary Greg Kroah-Hartman
2019-02-07 11:42 ` [PATCH 4.4 22/34] ip: discard IPv4 datagrams with overlapping segments Greg Kroah-Hartman
2019-02-07 11:42 ` [PATCH 4.4 23/34] net: modify skb_rbtree_purge to return the truesize of all purged skbs Greg Kroah-Hartman
2019-02-07 11:42 ` [PATCH 4.4 24/34] ipv6: defrag: drop non-last frags smaller than min mtu Greg Kroah-Hartman
2019-02-07 11:42 ` [PATCH 4.4 25/34] net: pskb_trim_rcsum() and CHECKSUM_COMPLETE are friends Greg Kroah-Hartman
2019-02-07 11:42 ` [PATCH 4.4 26/34] ip: use rb trees for IP frag queue Greg Kroah-Hartman
2019-02-07 11:42 ` [PATCH 4.4 27/34] ip: add helpers to process in-order fragments faster Greg Kroah-Hartman
2019-02-07 11:42 ` [PATCH 4.4 28/34] ip: process in-order fragments efficiently Greg Kroah-Hartman
2019-02-07 11:42 ` [PATCH 4.4 29/34] ip: frags: fix crash in ip_do_fragment() Greg Kroah-Hartman
2019-02-07 11:42 ` [PATCH 4.4 30/34] ipv4: frags: precedence bug in ip_expire() Greg Kroah-Hartman
2019-02-07 11:42 ` [PATCH 4.4 31/34] inet: frags: better deal with smp races Greg Kroah-Hartman
2019-02-07 11:42 ` [PATCH 4.4 32/34] net: fix pskb_trim_rcsum_slow() with odd trim offset Greg Kroah-Hartman
2019-02-07 11:42 ` [PATCH 4.4 33/34] net: ipv4: do not handle duplicate fragments as overlapping Greg Kroah-Hartman
2019-02-07 11:42 ` [PATCH 4.4 34/34] rcu: Force boolean subscript for expedited stall warnings Greg Kroah-Hartman
2019-02-07 14:20 ` [PATCH 4.4 00/34] 4.4.174-stable review Guenter Roeck
2019-02-07 14:41 ` Guenter Roeck
2019-02-07 15:46 ` Greg Kroah-Hartman
2019-02-07 18:57 ` Guenter Roeck
2019-02-07 15:47 ` Greg Kroah-Hartman
2019-02-07 19:16 ` Guenter Roeck
2019-02-07 18:18 ` kernelci.org bot
2019-02-08 6:13 ` Naresh Kamboju
2019-02-08 6:46 ` Greg Kroah-Hartman
2019-02-08 10:03 ` Jon Hunter
2019-02-08 10:28 ` Greg Kroah-Hartman
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