From 1ba5bf993c6a3142e18e68ea6452b347f9cb5635 Mon Sep 17 00:00:00 2001 From: Vegard Nossum Date: Tue, 5 Jul 2016 10:18:08 +0200 Subject: [PATCH] xfrm: fix crash in XFRM_MSG_GETSA netlink handler If we hit any of the error conditions inside xfrm_dump_sa(), then xfrm_state_walk_init() never gets called. However, we still call xfrm_state_walk_done() from xfrm_dump_sa_done(), which will crash because the state walk was never initialized properly. We can fix this by setting cb->args[0] only after we've processed the first element and checking this before calling xfrm_state_walk_done(). Fixes: d3623099d3 ("ipsec: add support of limited SA dump") Cc: Nicolas Dichtel Cc: Steffen Klassert Signed-off-by: Vegard Nossum Acked-by: Nicolas Dichtel Signed-off-by: Steffen Klassert --- net/xfrm/xfrm_user.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c index d516845e16e3..4fb04ced5867 100644 --- a/net/xfrm/xfrm_user.c +++ b/net/xfrm/xfrm_user.c @@ -896,7 +896,8 @@ static int xfrm_dump_sa_done(struct netlink_callback *cb) struct sock *sk = cb->skb->sk; struct net *net = sock_net(sk); - xfrm_state_walk_done(walk, net); + if (cb->args[0]) + xfrm_state_walk_done(walk, net); return 0; } @@ -921,8 +922,6 @@ static int xfrm_dump_sa(struct sk_buff *skb, struct netlink_callback *cb) u8 proto = 0; int err; - cb->args[0] = 1; - err = nlmsg_parse(cb->nlh, 0, attrs, XFRMA_MAX, xfrma_policy); if (err < 0) @@ -939,6 +938,7 @@ static int xfrm_dump_sa(struct sk_buff *skb, struct netlink_callback *cb) proto = nla_get_u8(attrs[XFRMA_PROTO]); xfrm_state_walk_init(walk, proto, filter); + cb->args[0] = 1; } (void) xfrm_state_walk(net, walk, dump_one_state, &info); -- 2.20.1