diff options
| author | weichenchen <weichen.chen@linux.alibaba.com> | 2020-12-25 13:44:45 +0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-12-28 14:49:48 -0800 |
| commit | a533b70a657c03137dd49cbcfee70aac086ab2b1 (patch) | |
| tree | ec36cd2b1aaea81ad270c0bb939a083d8a47829a /net/core | |
| parent | 21fdca22eb7df2a1e194b8adb812ce370748b733 (diff) | |
| download | lwn-a533b70a657c03137dd49cbcfee70aac086ab2b1.tar.gz lwn-a533b70a657c03137dd49cbcfee70aac086ab2b1.zip | |
net: neighbor: fix a crash caused by mod zero
pneigh_enqueue() tries to obtain a random delay by mod
NEIGH_VAR(p, PROXY_DELAY). However, NEIGH_VAR(p, PROXY_DELAY)
migth be zero at that point because someone could write zero
to /proc/sys/net/ipv4/neigh/[device]/proxy_delay after the
callers check it.
This patch uses prandom_u32_max() to get a random delay instead
which avoids potential division by zero.
Signed-off-by: weichenchen <weichen.chen@linux.alibaba.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/neighbour.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/net/core/neighbour.c b/net/core/neighbour.c index 9500d28a43b0..277ed854aef1 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -1569,10 +1569,8 @@ static void neigh_proxy_process(struct timer_list *t) void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p, struct sk_buff *skb) { - unsigned long now = jiffies; - - unsigned long sched_next = now + (prandom_u32() % - NEIGH_VAR(p, PROXY_DELAY)); + unsigned long sched_next = jiffies + + prandom_u32_max(NEIGH_VAR(p, PROXY_DELAY)); if (tbl->proxy_queue.qlen > NEIGH_VAR(p, PROXY_QLEN)) { kfree_skb(skb); |