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[SCTP]: Add RCU synchronization around sctp_localaddr_list

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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>
This commit is contained in:
Vlad Yasevich 2007-09-16 16:02:12 -07:00 • committed by David S. Miller
commit 2930354799
6 changed files with 97 additions and 38 deletions
Download patch file Download diff file Expand all files Collapse all files

38
net/sctp/socket.c
View file

@ -4057,9 +4057,9 @@ static int sctp_getsockopt_local_addrs_num_old(struct sock *sk, int len,
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 @@ static int sctp_getsockopt_local_addrs_num_old(struct sock *sk, int len,
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 @@ static int sctp_copy_laddrs_old(struct sock *sk, __u16 port,
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 @@ static int sctp_copy_laddrs_old(struct sock *sk, __u16 port,
cnt ++;
if (cnt >= max_addrs) break;
}
rcu_read_unlock();
return cnt;
}
@ -4156,14 +4163,16 @@ static int sctp_copy_laddrs_old(struct sock *sk, __u16 port,
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 @@ static int sctp_copy_laddrs(struct sock *sk, __u16 port, void *to,
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 @@ static int sctp_copy_laddrs(struct sock *sk, __u16 port, void *to,
space_left -= addrlen;
*bytes_copied += addrlen;
}
rcu_read_unlock();
return cnt;
}