diff options
author | Herbert Xu <herbert@gondor.apana.org.au> | 2017-10-19 15:51:10 +0300 |
---|---|---|
committer | Sasha Levin <alexander.levin@verizon.com> | 2017-12-09 02:01:13 +0300 |
commit | 5e80f6036c71f6ce1dbba0ad2925c331767f76ac (patch) | |
tree | c65cc123eecf1ec1fbd6c9550c7201f7a3e7a67d /net/xfrm | |
parent | 40bb024a89e588c618bc00f70d90bd9ef90b6fce (diff) | |
download | linux-5e80f6036c71f6ce1dbba0ad2925c331767f76ac.tar.xz |
ipsec: Fix aborted xfrm policy dump crash
[ Upstream commit 1137b5e2529a8f5ca8ee709288ecba3e68044df2 ]
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>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Diffstat (limited to 'net/xfrm')
-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 2091664295ba..18d9cf2eb648 100644 --- a/net/xfrm/xfrm_user.c +++ b/net/xfrm/xfrm_user.c @@ -1622,32 +1622,34 @@ 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; @@ -2383,6 +2385,7 @@ 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; @@ -2396,6 +2399,7 @@ 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 }, @@ -2447,6 +2451,7 @@ 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, }; |