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Bluetooth: Fix potential bad memory access with sysfs files 

When creating a high number of Bluetooth sockets (L2CAP, SCO
and RFCOMM) it is possible to scribble repeatedly on arbitrary
pages of memory. Ensure that the content of these sysfs files is
always less than one page. Even if this means truncating. The
files in question are scheduled to be moved over to debugfs in
the future anyway.

Based on initial patches from Neil Brown and Linus Torvalds

Reported-by: Neil Brown <neilb@suse.de>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
This commit is contained in:
Marcel Holtmann 2010-03-15 14:12:58 -07:00
parent af98441397
commit 101545f6fe
4 changed files with 41 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
net/bluetooth/l2cap.c
View File

@ -3944,16 +3944,24 @@ static ssize_t l2cap_sysfs_show(struct class *dev,
struct sock *sk;
struct hlist_node *node;
char *str = buf;
int size = PAGE_SIZE;
read_lock_bh(&l2cap_sk_list.lock);
sk_for_each(sk, node, &l2cap_sk_list.head) {
struct l2cap_pinfo *pi = l2cap_pi(sk);
int len;
str += sprintf(str, "%s %s %d %d 0x%4.4x 0x%4.4x %d %d %d\n",
len = snprintf(str, size, "%s %s %d %d 0x%4.4x 0x%4.4x %d %d %d\n",
batostr(&bt_sk(sk)->src), batostr(&bt_sk(sk)->dst),
sk->sk_state, __le16_to_cpu(pi->psm), pi->scid,
pi->dcid, pi->imtu, pi->omtu, pi->sec_level);
size -= len;
if (size <= 0)
break;
str += len;
}
read_unlock_bh(&l2cap_sk_list.lock);

13
net/bluetooth/rfcomm/core.c
View File

@ -2105,6 +2105,7 @@ static ssize_t rfcomm_dlc_sysfs_show(struct class *dev,
struct rfcomm_session *s;
struct list_head *pp, *p;
char *str = buf;
int size = PAGE_SIZE;
rfcomm_lock();
@ -2113,11 +2114,21 @@ static ssize_t rfcomm_dlc_sysfs_show(struct class *dev,
list_for_each(pp, &s->dlcs) {
struct sock *sk = s->sock->sk;
struct rfcomm_dlc *d = list_entry(pp, struct rfcomm_dlc, list);
int len;
str += sprintf(str, "%s %s %ld %d %d %d %d\n",
len = snprintf(str, size, "%s %s %ld %d %d %d %d\n",
batostr(&bt_sk(sk)->src), batostr(&bt_sk(sk)->dst),
d->state, d->dlci, d->mtu, d->rx_credits, d->tx_credits);
size -= len;
if (size <= 0)
break;
str += len;
}
if (size <= 0)
break;
}
rfcomm_unlock();

11
net/bluetooth/rfcomm/sock.c
View File

@ -1068,13 +1068,22 @@ static ssize_t rfcomm_sock_sysfs_show(struct class *dev,
struct sock *sk;
struct hlist_node *node;
char *str = buf;
int size = PAGE_SIZE;
read_lock_bh(&rfcomm_sk_list.lock);
sk_for_each(sk, node, &rfcomm_sk_list.head) {
str += sprintf(str, "%s %s %d %d\n",
int len;
len = snprintf(str, size, "%s %s %d %d\n",
batostr(&bt_sk(sk)->src), batostr(&bt_sk(sk)->dst),
sk->sk_state, rfcomm_pi(sk)->channel);
size -= len;
if (size <= 0)
break;
str += len;
}
read_unlock_bh(&rfcomm_sk_list.lock);

11
net/bluetooth/sco.c
View File

@ -960,13 +960,22 @@ static ssize_t sco_sysfs_show(struct class *dev,
struct sock *sk;
struct hlist_node *node;
char *str = buf;
int size = PAGE_SIZE;
read_lock_bh(&sco_sk_list.lock);
sk_for_each(sk, node, &sco_sk_list.head) {
str += sprintf(str, "%s %s %d\n",
int len;
len = snprintf(str, size, "%s %s %d\n",
batostr(&bt_sk(sk)->src), batostr(&bt_sk(sk)->dst),
sk->sk_state);
size -= len;
if (size <= 0)
break;
str += len;
}
read_unlock_bh(&sco_sk_list.lock);