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ipvs: fix racy memcpy in proc_do_sync_threshold

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commit 5310760af1d4fbea1452bfc77db5f9a680f7ae47 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Sishuai Gong 2023-08-10 15:12:42 -04:00 committed by Greg Kroah-Hartman
parent dbcfa782d9
commit 58a3d1d4b3
1 changed files with 4 additions and 0 deletions
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4
net/netfilter/ipvs/ip_vs_ctl.c
View File

@ -1682,6 +1682,7 @@ static int
proc_do_sync_threshold(struct ctl_table *table, int write, proc_do_sync_threshold(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos) void __user *buffer, size_t *lenp, loff_t *ppos)
{ {
struct netns_ipvs *ipvs = table->extra2;
int *valp = table->data; int *valp = table->data;
int val[2]; int val[2];
int rc; int rc;
@ -1691,6 +1692,7 @@ proc_do_sync_threshold(struct ctl_table *table, int write,
.mode = table->mode, .mode = table->mode,
}; };
mutex_lock(&ipvs->sync_mutex);
memcpy(val, valp, sizeof(val)); memcpy(val, valp, sizeof(val));
rc = proc_dointvec(&tmp, write, buffer, lenp, ppos); rc = proc_dointvec(&tmp, write, buffer, lenp, ppos);
if (write) { if (write) {
@ -1700,6 +1702,7 @@ proc_do_sync_threshold(struct ctl_table *table, int write,
else else
memcpy(valp, val, sizeof(val)); memcpy(valp, val, sizeof(val));
} }
mutex_unlock(&ipvs->sync_mutex);
return rc; return rc;
} }
@ -3976,6 +3979,7 @@ 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[0] = DEFAULT_SYNC_THRESHOLD;
ipvs->sysctl_sync_threshold[1] = DEFAULT_SYNC_PERIOD; ipvs->sysctl_sync_threshold[1] = DEFAULT_SYNC_PERIOD;
tbl[idx].data = &ipvs->sysctl_sync_threshold; tbl[idx].data = &ipvs->sysctl_sync_threshold;
tbl[idx].extra2 = ipvs;
tbl[idx++].maxlen = sizeof(ipvs->sysctl_sync_threshold); tbl[idx++].maxlen = sizeof(ipvs->sysctl_sync_threshold);
ipvs->sysctl_sync_refresh_period = DEFAULT_SYNC_REFRESH_PERIOD; ipvs->sysctl_sync_refresh_period = DEFAULT_SYNC_REFRESH_PERIOD;
tbl[idx++].data = &ipvs->sysctl_sync_refresh_period; tbl[idx++].data = &ipvs->sysctl_sync_refresh_period;