diff options
| author | Herbert Xu <herbert@gondor.apana.org.au> | 2017-10-19 20:51:10 +0800 |
|---|---|---|
| committer | Steffen Klassert <steffen.klassert@secunet.com> | 2017-10-23 09:35:48 +0200 |
| commit | 1137b5e2529a8f5ca8ee709288ecba3e68044df2 (patch) | |
| tree | 18edcb35fb0f74084d002b560f91fc9deb7a44e8 /net | |
| parent | 10a7ef33679073d13bf1dd05e3f1b7912f999543 (diff) | |
ipsec: Fix aborted xfrm policy dump crash
An independent security researcher, Mohamed Ghannam, has reported
this vulnerability to Beyond Security's SecuriTeam Secure Disclosure
program.
The xfrm_dump_policy_done function expects xfrm_dump_policy to
have been called at least once or it will crash. This can be
triggered if a dump fails because the target socket's receive
buffer is full.
This patch fixes it by using the cb->start mechanism to ensure that
the initialisation is always done regardless of the buffer situation.
Fixes: 12a169e7d8f4 ("ipsec: Put dumpers on the dump list")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Diffstat (limited to 'net')
| -rw-r--r-- | net/xfrm/xfrm_user.c | 25 |
1 files changed, 15 insertions, 10 deletions
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c index b997f1395357..e44a0fed48dd 100644 --- a/net/xfrm/xfrm_user.c +++ b/net/xfrm/xfrm_user.c @@ -1693,32 +1693,34 @@ static int dump_one_policy(struct xfrm_policy *xp, int dir, int count, void *ptr static int xfrm_dump_policy_done(struct netlink_callback *cb) { - struct xfrm_policy_walk *walk = (struct xfrm_policy_walk *) &cb->args[1]; + struct xfrm_policy_walk *walk = (struct xfrm_policy_walk *)cb->args; struct net *net = sock_net(cb->skb->sk); xfrm_policy_walk_done(walk, net); return 0; } +static int xfrm_dump_policy_start(struct netlink_callback *cb) +{ + struct xfrm_policy_walk *walk = (struct xfrm_policy_walk *)cb->args; + + BUILD_BUG_ON(sizeof(*walk) > sizeof(cb->args)); + + xfrm_policy_walk_init(walk, XFRM_POLICY_TYPE_ANY); + return 0; +} + static int xfrm_dump_policy(struct sk_buff *skb, struct netlink_callback *cb) { struct net *net = sock_net(skb->sk); - struct xfrm_policy_walk *walk = (struct xfrm_policy_walk *) &cb->args[1]; + struct xfrm_policy_walk *walk = (struct xfrm_policy_walk *)cb->args; struct xfrm_dump_info info; - BUILD_BUG_ON(sizeof(struct xfrm_policy_walk) > - sizeof(cb->args) - sizeof(cb->args[0])); - info.in_skb = cb->skb; info.out_skb = skb; info.nlmsg_seq = cb->nlh->nlmsg_seq; info.nlmsg_flags = NLM_F_MULTI; - if (!cb->args[0]) { - cb->args[0] = 1; - xfrm_policy_walk_init(walk, XFRM_POLICY_TYPE_ANY); - } - (void) xfrm_policy_walk(net, walk, dump_one_policy, &info); return skb->len; @@ -2474,6 +2476,7 @@ static const struct nla_policy xfrma_spd_policy[XFRMA_SPD_MAX+1] = { static const struct xfrm_link { int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **); + int (*start)(struct netlink_callback *); int (*dump)(struct sk_buff *, struct netlink_callback *); int (*done)(struct netlink_callback *); const struct nla_policy *nla_pol; @@ -2487,6 +2490,7 @@ static const struct xfrm_link { [XFRM_MSG_NEWPOLICY - XFRM_MSG_BASE] = { .doit = xfrm_add_policy }, [XFRM_MSG_DELPOLICY - XFRM_MSG_BASE] = { .doit = xfrm_get_policy }, [XFRM_MSG_GETPOLICY - XFRM_MSG_BASE] = { .doit = xfrm_get_policy, + .start = xfrm_dump_policy_start, .dump = xfrm_dump_policy, .done = xfrm_dump_policy_done }, [XFRM_MSG_ALLOCSPI - XFRM_MSG_BASE] = { .doit = xfrm_alloc_userspi }, @@ -2539,6 +2543,7 @@ static int xfrm_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, { struct netlink_dump_control c = { + .start = link->start, .dump = link->dump, .done = link->done, }; |