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authorStephen Hemminger <shemminger@linux-foundation.org>2007-10-11 04:30:46 +0400
committerDavid S. Miller <davem@davemloft.net>2007-10-11 04:30:46 +0400
commit227b60f5102cda4e4ab792b526a59c8cb20cd9f8 (patch)
tree2c9e372601ba794894833b0618bc531a9f5d57c4 /net/ipv6
parent06393009000779b00a558fd2f280882cc7dc2008 (diff)
downloadlinux-227b60f5102cda4e4ab792b526a59c8cb20cd9f8.tar.xz
[INET]: local port range robustness
Expansion of original idea from Denis V. Lunev <den@openvz.org> Add robustness and locking to the local_port_range sysctl. 1. Enforce that low < high when setting. 2. Use seqlock to ensure atomic update. The locking might seem like overkill, but there are cases where sysadmin might want to change value in the middle of a DoS attack. Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6')
-rw-r--r--net/ipv6/inet6_hashtables.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c
index ae6b0e7eb488..1c2c27655435 100644
--- a/net/ipv6/inet6_hashtables.c
+++ b/net/ipv6/inet6_hashtables.c
@@ -254,18 +254,18 @@ int inet6_hash_connect(struct inet_timewait_death_row *death_row,
int ret;
if (snum == 0) {
- const int low = sysctl_local_port_range[0];
- const int high = sysctl_local_port_range[1];
- const int range = high - low;
- int i, port;
+ int i, port, low, high, remaining;
static u32 hint;
const u32 offset = hint + inet6_sk_port_offset(sk);
struct hlist_node *node;
struct inet_timewait_sock *tw = NULL;
+ inet_get_local_port_range(&low, &high);
+ remaining = high - low;
+
local_bh_disable();
- for (i = 1; i <= range; i++) {
- port = low + (i + offset) % range;
+ for (i = 1; i <= remaining; i++) {
+ port = low + (i + offset) % remaining;
head = &hinfo->bhash[inet_bhashfn(port, hinfo->bhash_size)];
spin_lock(&head->lock);