User space may unload ip_set.ko while it is itself requesting a set type
backend module, leading to a kernel crash. The race condition may be
provoked by inserting an mdelay() right after the nfnl_unlock() call.
Fixes: a7b4f989a629 ("netfilter: ipset: IP set core support")
Signed-off-by: Phil Sutter <phil@xxxxxx>
---
net/netfilter/ipset/ip_set_core.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/net/netfilter/ipset/ip_set_core.c b/net/netfilter/ipset/ip_set_core.c
index 61431690cbd5..cc20e6d56807 100644
--- a/net/netfilter/ipset/ip_set_core.c
+++ b/net/netfilter/ipset/ip_set_core.c
@@ -104,14 +104,19 @@ find_set_type(const char *name, u8 family, u8 revision)
static bool
load_settype(const char *name)
{
+ if (!try_module_get(THIS_MODULE))
+ return false;
+
nfnl_unlock(NFNL_SUBSYS_IPSET);
pr_debug("try to load ip_set_%s\n", name);
if (request_module("ip_set_%s", name) < 0) {
pr_warn("Can't find ip_set type %s\n", name);
nfnl_lock(NFNL_SUBSYS_IPSET);
+ module_put(THIS_MODULE);
return false;
}
nfnl_lock(NFNL_SUBSYS_IPSET);
+ module_put(THIS_MODULE);
return true;
}
--
2.47.0
