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authorSishuai Gong <sishuai.system@gmail.com>2023-08-10 15:12:42 -0400
committerFlorian Westphal <fw@strlen.de>2023-08-16 00:05:15 +0200
commit5310760af1d4fbea1452bfc77db5f9a680f7ae47 (patch)
tree52c1ffadb87df2163b19482708e37ca567bc1638 /net
parent9bfab6d23a2865966a4f89a96536fbf23f83bc8c (diff)
ipvs: fix racy memcpy in proc_do_sync_threshold
When two threads run proc_do_sync_threshold() in parallel, data races could happen between the two memcpy(): Thread-1 Thread-2 memcpy(val, valp, sizeof(val)); memcpy(valp, val, sizeof(val)); This race might mess up the (struct ctl_table *) table->data, so we add a mutex lock to serialize them. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Link: https://lore.kernel.org/netdev/B6988E90-0A1E-4B85-BF26-2DAF6D482433@gmail.com/ Signed-off-by: Sishuai Gong <sishuai.system@gmail.com> Acked-by: Simon Horman <horms@kernel.org> Acked-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: Florian Westphal <fw@strlen.de>
Diffstat (limited to 'net')
-rw-r--r--net/netfilter/ipvs/ip_vs_ctl.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index 62606fb44d02..4bb0d90eca1c 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -1876,6 +1876,7 @@ static int
proc_do_sync_threshold(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
+ struct netns_ipvs *ipvs = table->extra2;
int *valp = table->data;
int val[2];
int rc;
@@ -1885,6 +1886,7 @@ proc_do_sync_threshold(struct ctl_table *table, int write,
.mode = table->mode,
};
+ mutex_lock(&ipvs->sync_mutex);
memcpy(val, valp, sizeof(val));
rc = proc_dointvec(&tmp, write, buffer, lenp, ppos);
if (write) {
@@ -1894,6 +1896,7 @@ proc_do_sync_threshold(struct ctl_table *table, int write,
else
memcpy(valp, val, sizeof(val));
}
+ mutex_unlock(&ipvs->sync_mutex);
return rc;
}
@@ -4321,6 +4324,7 @@ static int __net_init ip_vs_control_net_init_sysctl(struct netns_ipvs *ipvs)
ipvs->sysctl_sync_threshold[0] = DEFAULT_SYNC_THRESHOLD;
ipvs->sysctl_sync_threshold[1] = DEFAULT_SYNC_PERIOD;
tbl[idx].data = &ipvs->sysctl_sync_threshold;
+ tbl[idx].extra2 = ipvs;
tbl[idx++].maxlen = sizeof(ipvs->sysctl_sync_threshold);
ipvs->sysctl_sync_refresh_period = DEFAULT_SYNC_REFRESH_PERIOD;
tbl[idx++].data = &ipvs->sysctl_sync_refresh_period;