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Subject[PATCH v1 net 06/15] icmp: Fix a data-race around sysctl_icmp_echo_ignore_broadcasts.
Date
While reading sysctl_icmp_echo_ignore_broadcasts, it can be changed
concurrently. Thus, we need to add READ_ONCE() to its reader.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
net/ipv4/icmp.c | 2 +-
net/ipv4/sysctl_net_ipv4.c | 2 ++
2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index c406e324c594..4b1d84d3feaa 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -1249,7 +1249,7 @@ int icmp_rcv(struct sk_buff *skb)
*/
if ((icmph->type == ICMP_ECHO ||
icmph->type == ICMP_TIMESTAMP) &&
- net->ipv4.sysctl_icmp_echo_ignore_broadcasts) {
+ READ_ONCE(net->ipv4.sysctl_icmp_echo_ignore_broadcasts)) {
reason = SKB_DROP_REASON_INVALID_PROTO;
goto error;
}
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 64682a01914a..cb53476a292e 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -617,6 +617,8 @@ static struct ctl_table ipv4_net_table[] = {
.maxlen = sizeof(u8),
.mode = 0644,
.proc_handler = proc_dou8vec_minmax,
+ .extra1 = SYSCTL_ZERO,
+ .extra2 = SYSCTL_ONE
},
{
.procname = "icmp_ignore_bogus_error_responses",
--
2.30.2
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