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From: Eric Dumazet <edumazet@google.com>
To: "David S . Miller" <davem@davemloft.net>
Cc: netdev <netdev@vger.kernel.org>, Florian Westphal <fw@strlen.de>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	Thomas Graf <tgraf@suug.ch>,
	Jesper Dangaard Brouer <brouer@redhat.com>,
	Alexander Aring <alex.aring@gmail.com>,
	Stefan Schmidt <stefan@osg.samsung.com>,
	Kirill Tkhai <ktkhai@virtuozzo.com>,
	Eric Dumazet <edumazet@google.com>,
	Eric Dumazet <eric.dumazet@gmail.com>
Subject: [PATCH v2 net-next 12/12] inet: frags: break the 2GB limit for frags storage
Date: Fri, 30 Mar 2018 13:42:36 -0700	[thread overview]
Message-ID: <20180330204236.43675-13-edumazet@google.com> (raw)
In-Reply-To: <20180330204236.43675-1-edumazet@google.com>

Some users are willing to provision huge amounts of memory to be able
to perform reassembly reasonnably well under pressure.

Current memory tracking is using one atomic_t and integers.

Switch to atomic_long_t so that 64bit arches can use more than 2GB,
without any cost for 32bit arches.

Note that this patch avoids an overflow error, if high_thresh was set
to ~2GB, since this test in inet_frag_alloc() was never true :

if (... || frag_mem_limit(nf) > nf->high_thresh)

Tested:

$ echo 16000000000 >/proc/sys/net/ipv4/ipfrag_high_thresh

<frag DDOS>

$ grep FRAG /proc/net/sockstat
FRAG: inuse 14705885 memory 16000002880

$ nstat -n ; sleep 1 ; nstat | grep Reas
IpReasmReqds                    3317150            0.0
IpReasmFails                    3317112            0.0

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 Documentation/networking/ip-sysctl.txt  |  4 ++--
 include/net/inet_frag.h                 | 20 ++++++++++----------
 net/ieee802154/6lowpan/reassembly.c     | 10 +++++-----
 net/ipv4/ip_fragment.c                  | 10 +++++-----
 net/ipv4/proc.c                         |  2 +-
 net/ipv6/netfilter/nf_conntrack_reasm.c | 10 +++++-----
 net/ipv6/proc.c                         |  2 +-
 net/ipv6/reassembly.c                   |  6 +++---
 8 files changed, 32 insertions(+), 32 deletions(-)

diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 6f2a3670e44b6662ce53c16cb7ca1e4f61274c15..5dc1a040a2f1db610873de26c2d79bc57ac5a1a2 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -133,10 +133,10 @@ min_adv_mss - INTEGER
 
 IP Fragmentation:
 
-ipfrag_high_thresh - INTEGER
+ipfrag_high_thresh - LONG INTEGER
 	Maximum memory used to reassemble IP fragments.
 
-ipfrag_low_thresh - INTEGER
+ipfrag_low_thresh - LONG INTEGER
 	(Obsolete since linux-4.17)
 	Maximum memory used to reassemble IP fragments before the kernel
 	begins to remove incomplete fragment queues to free up resources.
diff --git a/include/net/inet_frag.h b/include/net/inet_frag.h
index 95e353e3305b43253084d972e32538138bcc5454..a52e7273e7a59bc8ce47b21d29235a740add8db0 100644
--- a/include/net/inet_frag.h
+++ b/include/net/inet_frag.h
@@ -8,11 +8,11 @@ struct netns_frags {
 	struct rhashtable       rhashtable ____cacheline_aligned_in_smp;
 
 	/* Keep atomic mem on separate cachelines in structs that include it */
-	atomic_t		mem ____cacheline_aligned_in_smp;
+	atomic_long_t		mem ____cacheline_aligned_in_smp;
 	/* sysctls */
+	long			high_thresh;
+	long			low_thresh;
 	int			timeout;
-	int			high_thresh;
-	int			low_thresh;
 	int			max_dist;
 	struct inet_frags	*f;
 };
@@ -102,7 +102,7 @@ void inet_frags_fini(struct inet_frags *);
 
 static inline int inet_frags_init_net(struct netns_frags *nf)
 {
-	atomic_set(&nf->mem, 0);
+	atomic_long_set(&nf->mem, 0);
 	return rhashtable_init(&nf->rhashtable, &nf->f->rhash_params);
 }
 void inet_frags_exit_net(struct netns_frags *nf);
@@ -119,19 +119,19 @@ static inline void inet_frag_put(struct inet_frag_queue *q)
 
 /* Memory Tracking Functions. */
 
-static inline int frag_mem_limit(struct netns_frags *nf)
+static inline long frag_mem_limit(const struct netns_frags *nf)
 {
-	return atomic_read(&nf->mem);
+	return atomic_long_read(&nf->mem);
 }
 
-static inline void sub_frag_mem_limit(struct netns_frags *nf, int i)
+static inline void sub_frag_mem_limit(struct netns_frags *nf, long val)
 {
-	atomic_sub(i, &nf->mem);
+	atomic_long_sub(val, &nf->mem);
 }
 
-static inline void add_frag_mem_limit(struct netns_frags *nf, int i)
+static inline void add_frag_mem_limit(struct netns_frags *nf, long val)
 {
-	atomic_add(i, &nf->mem);
+	atomic_long_add(val, &nf->mem);
 }
 
 /* RFC 3168 support :
diff --git a/net/ieee802154/6lowpan/reassembly.c b/net/ieee802154/6lowpan/reassembly.c
index 7eaa0617e277b829b801aee4e75f0ec61b2daf41..1f0857937ad187b48ff2af5e9c8570cf2b133fd2 100644
--- a/net/ieee802154/6lowpan/reassembly.c
+++ b/net/ieee802154/6lowpan/reassembly.c
@@ -411,23 +411,23 @@ int lowpan_frag_rcv(struct sk_buff *skb, u8 frag_type)
 }
 
 #ifdef CONFIG_SYSCTL
-static int zero;
+static long zero;
 
 static struct ctl_table lowpan_frags_ns_ctl_table[] = {
 	{
 		.procname	= "6lowpanfrag_high_thresh",
 		.data		= &init_net.ieee802154_lowpan.frags.high_thresh,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(unsigned long),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
+		.proc_handler	= proc_doulongvec_minmax,
 		.extra1		= &init_net.ieee802154_lowpan.frags.low_thresh
 	},
 	{
 		.procname	= "6lowpanfrag_low_thresh",
 		.data		= &init_net.ieee802154_lowpan.frags.low_thresh,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(unsigned long),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
+		.proc_handler	= proc_doulongvec_minmax,
 		.extra1		= &zero,
 		.extra2		= &init_net.ieee802154_lowpan.frags.high_thresh
 	},
diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
index b0366224f314ae521d8c1f8fe04c53e419292b4c..053869f2c49b9fd7a87316f1ef1416568b1bf508 100644
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -678,23 +678,23 @@ struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user)
 EXPORT_SYMBOL(ip_check_defrag);
 
 #ifdef CONFIG_SYSCTL
-static int zero;
+static long zero;
 
 static struct ctl_table ip4_frags_ns_ctl_table[] = {
 	{
 		.procname	= "ipfrag_high_thresh",
 		.data		= &init_net.ipv4.frags.high_thresh,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(unsigned long),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
+		.proc_handler	= proc_doulongvec_minmax,
 		.extra1		= &init_net.ipv4.frags.low_thresh
 	},
 	{
 		.procname	= "ipfrag_low_thresh",
 		.data		= &init_net.ipv4.frags.low_thresh,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(unsigned long),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
+		.proc_handler	= proc_doulongvec_minmax,
 		.extra1		= &zero,
 		.extra2		= &init_net.ipv4.frags.high_thresh
 	},
diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c
index aacfce0d7d82cf59269a69ef4d6ac8d9955b0bdc..a058de677e947846eb93020e0788148827c8f3cd 100644
--- a/net/ipv4/proc.c
+++ b/net/ipv4/proc.c
@@ -71,7 +71,7 @@ static int sockstat_seq_show(struct seq_file *seq, void *v)
 		   sock_prot_inuse_get(net, &udplite_prot));
 	seq_printf(seq, "RAW: inuse %d\n",
 		   sock_prot_inuse_get(net, &raw_prot));
-	seq_printf(seq,  "FRAG: inuse %u memory %u\n",
+	seq_printf(seq,  "FRAG: inuse %u memory %lu\n",
 		   atomic_read(&net->ipv4.frags.rhashtable.nelems),
 		   frag_mem_limit(&net->ipv4.frags));
 	return 0;
diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c b/net/ipv6/netfilter/nf_conntrack_reasm.c
index d866412b8f6c432f04c0968f08f820fdc561262b..603a395928593a071aff28105578d3bfdbf1b31e 100644
--- a/net/ipv6/netfilter/nf_conntrack_reasm.c
+++ b/net/ipv6/netfilter/nf_conntrack_reasm.c
@@ -63,7 +63,7 @@ struct nf_ct_frag6_skb_cb
 static struct inet_frags nf_frags;
 
 #ifdef CONFIG_SYSCTL
-static int zero;
+static long zero;
 
 static struct ctl_table nf_ct_frag6_sysctl_table[] = {
 	{
@@ -76,18 +76,18 @@ static struct ctl_table nf_ct_frag6_sysctl_table[] = {
 	{
 		.procname	= "nf_conntrack_frag6_low_thresh",
 		.data		= &init_net.nf_frag.frags.low_thresh,
-		.maxlen		= sizeof(unsigned int),
+		.maxlen		= sizeof(unsigned long),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
+		.proc_handler	= proc_doulongvec_minmax,
 		.extra1		= &zero,
 		.extra2		= &init_net.nf_frag.frags.high_thresh
 	},
 	{
 		.procname	= "nf_conntrack_frag6_high_thresh",
 		.data		= &init_net.nf_frag.frags.high_thresh,
-		.maxlen		= sizeof(unsigned int),
+		.maxlen		= sizeof(unsigned long),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
+		.proc_handler	= proc_doulongvec_minmax,
 		.extra1		= &init_net.nf_frag.frags.low_thresh
 	},
 	{ }
diff --git a/net/ipv6/proc.c b/net/ipv6/proc.c
index 8befeb91e0712ecc4d05c4c0a6ecca1808dcbcac..a85f7e0b14b10f59fdd2ea6901f8e9a95c13654f 100644
--- a/net/ipv6/proc.c
+++ b/net/ipv6/proc.c
@@ -47,7 +47,7 @@ static int sockstat6_seq_show(struct seq_file *seq, void *v)
 			sock_prot_inuse_get(net, &udplitev6_prot));
 	seq_printf(seq, "RAW6: inuse %d\n",
 		       sock_prot_inuse_get(net, &rawv6_prot));
-	seq_printf(seq, "FRAG6: inuse %u memory %u\n",
+	seq_printf(seq, "FRAG6: inuse %u memory %lu\n",
 		   atomic_read(&net->ipv6.frags.rhashtable.nelems),
 		   frag_mem_limit(&net->ipv6.frags));
 	return 0;
diff --git a/net/ipv6/reassembly.c b/net/ipv6/reassembly.c
index 2a77fda5e3bca1b6ce8c24df11e741653a15c665..905a8aee2671fd76b47d9cc6b6b0c17c9691d224 100644
--- a/net/ipv6/reassembly.c
+++ b/net/ipv6/reassembly.c
@@ -552,15 +552,15 @@ static struct ctl_table ip6_frags_ns_ctl_table[] = {
 	{
 		.procname	= "ip6frag_high_thresh",
 		.data		= &init_net.ipv6.frags.high_thresh,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(unsigned long),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
+		.proc_handler	= proc_doulongvec_minmax,
 		.extra1		= &init_net.ipv6.frags.low_thresh
 	},
 	{
 		.procname	= "ip6frag_low_thresh",
 		.data		= &init_net.ipv6.frags.low_thresh,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(unsigned long),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
 		.extra1		= &zero,
-- 
2.17.0.rc1.321.gba9d0f2565-goog

      parent reply	other threads:[~2018-03-30 20:44 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-30 20:42 [PATCH v2 net-next 00/12] inet: frags: bring rhashtables to IP defrag Eric Dumazet
2018-03-30 20:42 ` [PATCH v2 net-next 01/12] ipv6: frag: remove unused field Eric Dumazet
2018-03-30 20:42 ` [PATCH v2 net-next 02/12] inet: frags: change inet_frags_init_net() return value Eric Dumazet
2018-03-30 20:42 ` [PATCH v2 net-next 03/12] inet: frags: add a pointer to struct netns_frags Eric Dumazet
2018-03-30 20:42 ` [PATCH v2 net-next 04/12] inet: frags: refactor ipv6_frag_init() Eric Dumazet
2018-03-30 20:42 ` [PATCH v2 net-next 05/12] inet: frags: refactor lowpan_net_frag_init() Eric Dumazet
2018-03-30 20:42 ` [PATCH v2 net-next 06/12] inet: frags: refactor ipfrag_init() Eric Dumazet
2018-03-30 20:42 ` [PATCH v2 net-next 07/12] rhashtable: add schedule points Eric Dumazet
2018-03-31  4:19   ` Herbert Xu
2018-03-30 20:42 ` [PATCH v2 net-next 08/12] inet: frags: use rhashtables for reassembly units Eric Dumazet
2018-03-30 22:43   ` Eric Dumazet
2018-03-30 22:44   ` Kirill Tkhai
2018-03-30 22:54     ` Eric Dumazet
2018-03-30 20:42 ` [PATCH v2 net-next 09/12] inet: frags: remove some helpers Eric Dumazet
2018-03-30 20:42 ` [PATCH v2 net-next 10/12] inet: frags: get rif of inet_frag_evicting() Eric Dumazet
2018-03-30 20:42 ` [PATCH v2 net-next 11/12] inet: frags: remove inet_frag_maybe_warn_overflow() Eric Dumazet
2018-03-30 20:42 ` Eric Dumazet [this message]

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