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authorYuejie Shi <syjcnss@gmail.com>2017-03-31 15:10:20 +0800
committerSteffen Klassert <steffen.klassert@secunet.com>2017-04-03 08:05:17 +0200
commit89e357d83c06b6fac581c3ca7f0ee3ae7e67109e (patch)
tree95c3425ed24cca1ce0b806197c690ca42c1be36b /net
parent75514b6654859e0130b512396dc964d2a9e84967 (diff)
af_key: Add lock to key dump
A dump may come in the middle of another dump, modifying its dump structure members. This race condition will result in NULL pointer dereference in kernel. So add a lock to prevent that race. Fixes: 83321d6b9872 ("[AF_KEY]: Dump SA/SP entries non-atomically") Signed-off-by: Yuejie Shi <syjcnss@gmail.com> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Diffstat (limited to 'net')
-rw-r--r--net/key/af_key.c46
1 files changed, 38 insertions, 8 deletions
diff --git a/net/key/af_key.c b/net/key/af_key.c
index c6252ed42c1d..1b0ea80133f1 100644
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -63,6 +63,7 @@ struct pfkey_sock {
} u;
struct sk_buff *skb;
} dump;
+ struct mutex dump_lock;
};
static inline struct pfkey_sock *pfkey_sk(struct sock *sk)
@@ -139,6 +140,7 @@ static int pfkey_create(struct net *net, struct socket *sock, int protocol,
{
struct netns_pfkey *net_pfkey = net_generic(net, pfkey_net_id);
struct sock *sk;
+ struct pfkey_sock *pfk;
int err;
if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
@@ -153,6 +155,9 @@ static int pfkey_create(struct net *net, struct socket *sock, int protocol,
if (sk == NULL)
goto out;
+ pfk = pfkey_sk(sk);
+ mutex_init(&pfk->dump_lock);
+
sock->ops = &pfkey_ops;
sock_init_data(sock, sk);
@@ -281,13 +286,23 @@ static int pfkey_do_dump(struct pfkey_sock *pfk)
struct sadb_msg *hdr;
int rc;
+ mutex_lock(&pfk->dump_lock);
+ if (!pfk->dump.dump) {
+ rc = 0;
+ goto out;
+ }
+
rc = pfk->dump.dump(pfk);
- if (rc == -ENOBUFS)
- return 0;
+ if (rc == -ENOBUFS) {
+ rc = 0;
+ goto out;
+ }
if (pfk->dump.skb) {
- if (!pfkey_can_dump(&pfk->sk))
- return 0;
+ if (!pfkey_can_dump(&pfk->sk)) {
+ rc = 0;
+ goto out;
+ }
hdr = (struct sadb_msg *) pfk->dump.skb->data;
hdr->sadb_msg_seq = 0;
@@ -298,6 +313,9 @@ static int pfkey_do_dump(struct pfkey_sock *pfk)
}
pfkey_terminate_dump(pfk);
+
+out:
+ mutex_unlock(&pfk->dump_lock);
return rc;
}
@@ -1793,19 +1811,26 @@ static int pfkey_dump(struct sock *sk, struct sk_buff *skb, const struct sadb_ms
struct xfrm_address_filter *filter = NULL;
struct pfkey_sock *pfk = pfkey_sk(sk);
- if (pfk->dump.dump != NULL)
+ mutex_lock(&pfk->dump_lock);
+ if (pfk->dump.dump != NULL) {
+ mutex_unlock(&pfk->dump_lock);
return -EBUSY;
+ }
proto = pfkey_satype2proto(hdr->sadb_msg_satype);
- if (proto == 0)
+ if (proto == 0) {
+ mutex_unlock(&pfk->dump_lock);
return -EINVAL;
+ }
if (ext_hdrs[SADB_X_EXT_FILTER - 1]) {
struct sadb_x_filter *xfilter = ext_hdrs[SADB_X_EXT_FILTER - 1];
filter = kmalloc(sizeof(*filter), GFP_KERNEL);
- if (filter == NULL)
+ if (filter == NULL) {
+ mutex_unlock(&pfk->dump_lock);
return -ENOMEM;
+ }
memcpy(&filter->saddr, &xfilter->sadb_x_filter_saddr,
sizeof(xfrm_address_t));
@@ -1821,6 +1846,7 @@ static int pfkey_dump(struct sock *sk, struct sk_buff *skb, const struct sadb_ms
pfk->dump.dump = pfkey_dump_sa;
pfk->dump.done = pfkey_dump_sa_done;
xfrm_state_walk_init(&pfk->dump.u.state, proto, filter);
+ mutex_unlock(&pfk->dump_lock);
return pfkey_do_dump(pfk);
}
@@ -2679,14 +2705,18 @@ static int pfkey_spddump(struct sock *sk, struct sk_buff *skb, const struct sadb
{
struct pfkey_sock *pfk = pfkey_sk(sk);
- if (pfk->dump.dump != NULL)
+ mutex_lock(&pfk->dump_lock);
+ if (pfk->dump.dump != NULL) {
+ mutex_unlock(&pfk->dump_lock);
return -EBUSY;
+ }
pfk->dump.msg_version = hdr->sadb_msg_version;
pfk->dump.msg_portid = hdr->sadb_msg_pid;
pfk->dump.dump = pfkey_dump_sp;
pfk->dump.done = pfkey_dump_sp_done;
xfrm_policy_walk_init(&pfk->dump.u.policy, XFRM_POLICY_TYPE_MAIN);
+ mutex_unlock(&pfk->dump_lock);
return pfkey_do_dump(pfk);
}