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[INET]: local port range robustness

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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>
This commit is contained in:
Stephen Hemminger
2007-10-10 17:30:46 -07:00
committed by David S. Miller
parent 0639300900
commit 227b60f510
10 changed files with 146 additions and 58 deletions
Download Patch File Download Diff File Expand all files Collapse all files

22
drivers/infiniband/core/cma.c
View File

@@ -1866,13 +1866,14 @@ err1:
static int cma_alloc_any_port(struct idr *ps, struct rdma_id_private *id_priv)
{
struct rdma_bind_list *bind_list;
int port, ret;
int port, ret, low, high;
bind_list = kzalloc(sizeof *bind_list, GFP_KERNEL);
if (!bind_list)
return -ENOMEM;
retry:
/* FIXME: add proper port randomization per like inet_csk_get_port */
do {
ret = idr_get_new_above(ps, bind_list, next_port, &port);
} while ((ret == -EAGAIN) && idr_pre_get(ps, GFP_KERNEL));
@@ -1880,18 +1881,19 @@ retry:
if (ret)
goto err1;
if (port > sysctl_local_port_range[1]) {
if (next_port != sysctl_local_port_range[0]) {
inet_get_local_port_range(&low, &high);
if (port > high) {
if (next_port != low) {
idr_remove(ps, port);
next_port = sysctl_local_port_range[0];
next_port = low;
goto retry;
}
ret = -EADDRNOTAVAIL;
goto err2;
}
if (port == sysctl_local_port_range[1])
next_port = sysctl_local_port_range[0];
if (port == high)
next_port = low;
else
next_port = port + 1;
@@ -2769,12 +2771,12 @@ static void cma_remove_one(struct ib_device *device)
static int cma_init(void)
{
int ret;
int ret, low, high;
get_random_bytes(&next_port, sizeof next_port);
next_port = ((unsigned int) next_port %
(sysctl_local_port_range[1] - sysctl_local_port_range[0])) +
sysctl_local_port_range[0];
inet_get_local_port_range(&low, &high);
next_port = ((unsigned int) next_port % (high - low)) + low;
cma_wq = create_singlethread_workqueue("rdma_cm");
if (!cma_wq)
return -ENOMEM;