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-rw-r--r--Documentation/networking/ip-sysctl.txt23
-rw-r--r--include/linux/sysctl.h1
-rw-r--r--include/net/inetpeer.h1
-rw-r--r--include/net/ip.h2
-rw-r--r--net/ipv4/inetpeer.c1
-rw-r--r--net/ipv4/ip_fragment.c68
-rw-r--r--net/ipv4/ip_output.c1
-rw-r--r--net/ipv4/sysctl_net_ipv4.c10
8 files changed, 106 insertions, 1 deletions
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index ebc09a159f6..2b7cf19a06a 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -46,6 +46,29 @@ ipfrag_secret_interval - INTEGER
for the hash secret) for IP fragments.
Default: 600
+ipfrag_max_dist - INTEGER
+ ipfrag_max_dist is a non-negative integer value which defines the
+ maximum "disorder" which is allowed among fragments which share a
+ common IP source address. Note that reordering of packets is
+ not unusual, but if a large number of fragments arrive from a source
+ IP address while a particular fragment queue remains incomplete, it
+ probably indicates that one or more fragments belonging to that queue
+ have been lost. When ipfrag_max_dist is positive, an additional check
+ is done on fragments before they are added to a reassembly queue - if
+ ipfrag_max_dist (or more) fragments have arrived from a particular IP
+ address between additions to any IP fragment queue using that source
+ address, it's presumed that one or more fragments in the queue are
+ lost. The existing fragment queue will be dropped, and a new one
+ started. An ipfrag_max_dist value of zero disables this check.
+
+ Using a very small value, e.g. 1 or 2, for ipfrag_max_dist can
+ result in unnecessarily dropping fragment queues when normal
+ reordering of packets occurs, which could lead to poor application
+ performance. Using a very large value, e.g. 50000, increases the
+ likelihood of incorrectly reassembling IP fragments that originate
+ from different IP datagrams, which could result in data corruption.
+ Default: 64
+
INET peer storage:
inet_peer_threshold - INTEGER
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 4be34ef8c2f..93fa765e47d 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -390,6 +390,7 @@ enum
NET_IPV4_ICMP_ERRORS_USE_INBOUND_IFADDR=109,
NET_TCP_CONG_CONTROL=110,
NET_TCP_ABC=111,
+ NET_IPV4_IPFRAG_MAX_DIST=112,
};
enum {
diff --git a/include/net/inetpeer.h b/include/net/inetpeer.h
index 7fda471002b..0965515f40c 100644
--- a/include/net/inetpeer.h
+++ b/include/net/inetpeer.h
@@ -25,6 +25,7 @@ struct inet_peer
__u32 v4daddr; /* peer's address */
__u16 avl_height;
__u16 ip_id_count; /* IP ID for the next packet */
+ atomic_t rid; /* Frag reception counter */
__u32 tcp_ts;
unsigned long tcp_ts_stamp;
};
diff --git a/include/net/ip.h b/include/net/ip.h
index e4563bbee6e..4d6294ba038 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -45,6 +45,7 @@ struct inet_skb_parm
#define IPSKB_TRANSLATED 2
#define IPSKB_FORWARDED 4
#define IPSKB_XFRM_TUNNEL_SIZE 8
+#define IPSKB_FRAG_COMPLETE 16
};
struct ipcm_cookie
@@ -168,6 +169,7 @@ extern int sysctl_ipfrag_high_thresh;
extern int sysctl_ipfrag_low_thresh;
extern int sysctl_ipfrag_time;
extern int sysctl_ipfrag_secret_interval;
+extern int sysctl_ipfrag_max_dist;
/* From inetpeer.c */
extern int inet_peer_threshold;
diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c
index 2fc3fd38924..ce5fe3f74a3 100644
--- a/net/ipv4/inetpeer.c
+++ b/net/ipv4/inetpeer.c
@@ -401,6 +401,7 @@ struct inet_peer *inet_getpeer(__u32 daddr, int create)
return NULL;
n->v4daddr = daddr;
atomic_set(&n->refcnt, 1);
+ atomic_set(&n->rid, 0);
n->ip_id_count = secure_ip_id(daddr);
n->tcp_ts_stamp = 0;
diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
index 8ce0ce2ee48..ce2b70ce401 100644
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -22,6 +22,7 @@
* Patrick McHardy : LRU queue of frag heads for evictor.
*/
+#include <linux/compiler.h>
#include <linux/config.h>
#include <linux/module.h>
#include <linux/types.h>
@@ -38,6 +39,7 @@
#include <net/ip.h>
#include <net/icmp.h>
#include <net/checksum.h>
+#include <net/inetpeer.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/inet.h>
@@ -56,6 +58,8 @@
int sysctl_ipfrag_high_thresh = 256*1024;
int sysctl_ipfrag_low_thresh = 192*1024;
+int sysctl_ipfrag_max_dist = 64;
+
/* Important NOTE! Fragment queue must be destroyed before MSL expires.
* RFC791 is wrong proposing to prolongate timer each fragment arrival by TTL.
*/
@@ -89,8 +93,10 @@ struct ipq {
spinlock_t lock;
atomic_t refcnt;
struct timer_list timer; /* when will this queue expire? */
- int iif;
struct timeval stamp;
+ int iif;
+ unsigned int rid;
+ struct inet_peer *peer;
};
/* Hash table. */
@@ -195,6 +201,9 @@ static void ip_frag_destroy(struct ipq *qp, int *work)
BUG_TRAP(qp->last_in&COMPLETE);
BUG_TRAP(del_timer(&qp->timer) == 0);
+ if (qp->peer)
+ inet_putpeer(qp->peer);
+
/* Release all fragment data. */
fp = qp->fragments;
while (fp) {
@@ -353,6 +362,7 @@ static struct ipq *ip_frag_create(unsigned hash, struct iphdr *iph, u32 user)
qp->meat = 0;
qp->fragments = NULL;
qp->iif = 0;
+ qp->peer = sysctl_ipfrag_max_dist ? inet_getpeer(iph->saddr, 1) : NULL;
/* Initialize a timer for this entry. */
init_timer(&qp->timer);
@@ -398,6 +408,56 @@ static inline struct ipq *ip_find(struct iphdr *iph, u32 user)
return ip_frag_create(hash, iph, user);
}
+/* Is the fragment too far ahead to be part of ipq? */
+static inline int ip_frag_too_far(struct ipq *qp)
+{
+ struct inet_peer *peer = qp->peer;
+ unsigned int max = sysctl_ipfrag_max_dist;
+ unsigned int start, end;
+
+ int rc;
+
+ if (!peer || !max)
+ return 0;
+
+ start = qp->rid;
+ end = atomic_inc_return(&peer->rid);
+ qp->rid = end;
+
+ rc = qp->fragments && (end - start) > max;
+
+ if (rc) {
+ IP_INC_STATS_BH(IPSTATS_MIB_REASMFAILS);
+ }
+
+ return rc;
+}
+
+static int ip_frag_reinit(struct ipq *qp)
+{
+ struct sk_buff *fp;
+
+ if (!mod_timer(&qp->timer, jiffies + sysctl_ipfrag_time)) {
+ atomic_inc(&qp->refcnt);
+ return -ETIMEDOUT;
+ }
+
+ fp = qp->fragments;
+ do {
+ struct sk_buff *xp = fp->next;
+ frag_kfree_skb(fp, NULL);
+ fp = xp;
+ } while (fp);
+
+ qp->last_in = 0;
+ qp->len = 0;
+ qp->meat = 0;
+ qp->fragments = NULL;
+ qp->iif = 0;
+
+ return 0;
+}
+
/* Add new segment to existing queue. */
static void ip_frag_queue(struct ipq *qp, struct sk_buff *skb)
{
@@ -408,6 +468,12 @@ static void ip_frag_queue(struct ipq *qp, struct sk_buff *skb)
if (qp->last_in & COMPLETE)
goto err;
+ if (!(IPCB(skb)->flags & IPSKB_FRAG_COMPLETE) &&
+ unlikely(ip_frag_too_far(qp)) && unlikely(ip_frag_reinit(qp))) {
+ ipq_kill(qp);
+ goto err;
+ }
+
offset = ntohs(skb->nh.iph->frag_off);
flags = offset & ~IP_OFFSET;
offset &= IP_OFFSET;
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index eba64e2bd39..2a830de3a69 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -445,6 +445,7 @@ int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff*))
hlen = iph->ihl * 4;
mtu = dst_mtu(&rt->u.dst) - hlen; /* Size of data space */
+ IPCB(skb)->flags |= IPSKB_FRAG_COMPLETE;
/* When frag_list is given, use it. First, check its validity:
* some transformers could create wrong frag_list or break existing
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 01444a02b48..dbf82955aab 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -22,6 +22,7 @@
extern int sysctl_ip_nonlocal_bind;
#ifdef CONFIG_SYSCTL
+static int zero;
static int tcp_retr1_max = 255;
static int ip_local_port_range_min[] = { 1, 1 };
static int ip_local_port_range_max[] = { 65535, 65535 };
@@ -614,6 +615,15 @@ ctl_table ipv4_table[] = {
.strategy = &sysctl_jiffies
},
{
+ .ctl_name = NET_IPV4_IPFRAG_MAX_DIST,
+ .procname = "ipfrag_max_dist",
+ .data = &sysctl_ipfrag_max_dist,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec_minmax,
+ .extra1 = &zero
+ },
+ {
.ctl_name = NET_TCP_NO_METRICS_SAVE,
.procname = "tcp_no_metrics_save",
.data = &sysctl_tcp_nometrics_save,