[SCTP]: Add RCU synchronization around sctp_localaddr_list
sctp_localaddr_list is modified dynamically via NETDEV_UP
and NETDEV_DOWN events, but there is not synchronization
between writer (even handler) and readers. As a result,
the readers can access an entry that has been freed and
crash the sytem.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Sridhar Samdurala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 3335460..a3acf78 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -4057,9 +4057,9 @@
int __user *optlen)
{
sctp_assoc_t id;
+ struct list_head *pos;
struct sctp_bind_addr *bp;
struct sctp_association *asoc;
- struct list_head *pos, *temp;
struct sctp_sockaddr_entry *addr;
rwlock_t *addr_lock;
int cnt = 0;
@@ -4096,15 +4096,19 @@
addr = list_entry(bp->address_list.next,
struct sctp_sockaddr_entry, list);
if (sctp_is_any(&addr->a)) {
- list_for_each_safe(pos, temp, &sctp_local_addr_list) {
- addr = list_entry(pos,
- struct sctp_sockaddr_entry,
- list);
+ rcu_read_lock();
+ list_for_each_entry_rcu(addr,
+ &sctp_local_addr_list, list) {
+ if (!addr->valid)
+ continue;
+
if ((PF_INET == sk->sk_family) &&
(AF_INET6 == addr->a.sa.sa_family))
continue;
+
cnt++;
}
+ rcu_read_unlock();
} else {
cnt = 1;
}
@@ -4127,14 +4131,16 @@
int max_addrs, void *to,
int *bytes_copied)
{
- struct list_head *pos, *next;
struct sctp_sockaddr_entry *addr;
union sctp_addr temp;
int cnt = 0;
int addrlen;
- list_for_each_safe(pos, next, &sctp_local_addr_list) {
- addr = list_entry(pos, struct sctp_sockaddr_entry, list);
+ rcu_read_lock();
+ list_for_each_entry_rcu(addr, &sctp_local_addr_list, list) {
+ if (!addr->valid)
+ continue;
+
if ((PF_INET == sk->sk_family) &&
(AF_INET6 == addr->a.sa.sa_family))
continue;
@@ -4149,6 +4155,7 @@
cnt ++;
if (cnt >= max_addrs) break;
}
+ rcu_read_unlock();
return cnt;
}
@@ -4156,14 +4163,16 @@
static int sctp_copy_laddrs(struct sock *sk, __u16 port, void *to,
size_t space_left, int *bytes_copied)
{
- struct list_head *pos, *next;
struct sctp_sockaddr_entry *addr;
union sctp_addr temp;
int cnt = 0;
int addrlen;
- list_for_each_safe(pos, next, &sctp_local_addr_list) {
- addr = list_entry(pos, struct sctp_sockaddr_entry, list);
+ rcu_read_lock();
+ list_for_each_entry_rcu(addr, &sctp_local_addr_list, list) {
+ if (!addr->valid)
+ continue;
+
if ((PF_INET == sk->sk_family) &&
(AF_INET6 == addr->a.sa.sa_family))
continue;
@@ -4171,8 +4180,10 @@
sctp_get_pf_specific(sk->sk_family)->addr_v4map(sctp_sk(sk),
&temp);
addrlen = sctp_get_af_specific(temp.sa.sa_family)->sockaddr_len;
- if (space_left < addrlen)
- return -ENOMEM;
+ if (space_left < addrlen) {
+ cnt = -ENOMEM;
+ break;
+ }
memcpy(to, &temp, addrlen);
to += addrlen;
@@ -4180,6 +4191,7 @@
space_left -= addrlen;
*bytes_copied += addrlen;
}
+ rcu_read_unlock();
return cnt;
}
