From: Nicolas Dichtel <nicolas.dichtel@xxxxxxxxx>
commit 93ec1320b0170d7a207eda2d119c669b673401ed upstream.
As stated in the comment above xfrm_nlmsg_multicast(), rcu read lock must
be held before calling this function.
Reported-by: syzbot+3d9866419b4aa8f985d6@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 703b94b93c19 ("xfrm: notify default policy on update")
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@xxxxxxxxx>
Signed-off-by: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/xfrm/xfrm_user.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -1920,6 +1920,7 @@ static int xfrm_notify_userpolicy(struct
int len = NLMSG_ALIGN(sizeof(*up));
struct nlmsghdr *nlh;
struct sk_buff *skb;
+ int err;
skb = nlmsg_new(len, GFP_ATOMIC);
if (skb == NULL)
@@ -1938,7 +1939,11 @@ static int xfrm_notify_userpolicy(struct
nlmsg_end(skb, nlh);
- return xfrm_nlmsg_multicast(net, skb, 0, XFRMNLGRP_POLICY);
+ rcu_read_lock();
+ err = xfrm_nlmsg_multicast(net, skb, 0, XFRMNLGRP_POLICY);
+ rcu_read_unlock();
+
+ return err;
}
static bool xfrm_userpolicy_is_valid(__u8 policy)
