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>
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@ -3944,16 +3944,24 @@ static ssize_t l2cap_sysfs_show(struct class *dev,
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struct sock *sk;
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struct hlist_node *node;
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char *str = buf;
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int size = PAGE_SIZE;
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read_lock_bh(&l2cap_sk_list.lock);
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sk_for_each(sk, node, &l2cap_sk_list.head) {
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struct l2cap_pinfo *pi = l2cap_pi(sk);
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int len;
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str += sprintf(str, "%s %s %d %d 0x%4.4x 0x%4.4x %d %d %d\n",
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len = snprintf(str, size, "%s %s %d %d 0x%4.4x 0x%4.4x %d %d %d\n",
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batostr(&bt_sk(sk)->src), batostr(&bt_sk(sk)->dst),
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sk->sk_state, __le16_to_cpu(pi->psm), pi->scid,
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pi->dcid, pi->imtu, pi->omtu, pi->sec_level);
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size -= len;
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if (size <= 0)
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break;
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str += len;
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}
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read_unlock_bh(&l2cap_sk_list.lock);
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@ -2105,6 +2105,7 @@ static ssize_t rfcomm_dlc_sysfs_show(struct class *dev,
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struct rfcomm_session *s;
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struct list_head *pp, *p;
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char *str = buf;
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int size = PAGE_SIZE;
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rfcomm_lock();
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@ -2113,11 +2114,21 @@ static ssize_t rfcomm_dlc_sysfs_show(struct class *dev,
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list_for_each(pp, &s->dlcs) {
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struct sock *sk = s->sock->sk;
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struct rfcomm_dlc *d = list_entry(pp, struct rfcomm_dlc, list);
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int len;
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str += sprintf(str, "%s %s %ld %d %d %d %d\n",
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len = snprintf(str, size, "%s %s %ld %d %d %d %d\n",
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batostr(&bt_sk(sk)->src), batostr(&bt_sk(sk)->dst),
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d->state, d->dlci, d->mtu, d->rx_credits, d->tx_credits);
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size -= len;
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if (size <= 0)
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break;
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str += len;
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}
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if (size <= 0)
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break;
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}
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rfcomm_unlock();
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@ -1068,13 +1068,22 @@ static ssize_t rfcomm_sock_sysfs_show(struct class *dev,
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struct sock *sk;
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struct hlist_node *node;
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char *str = buf;
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int size = PAGE_SIZE;
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read_lock_bh(&rfcomm_sk_list.lock);
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sk_for_each(sk, node, &rfcomm_sk_list.head) {
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str += sprintf(str, "%s %s %d %d\n",
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int len;
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len = snprintf(str, size, "%s %s %d %d\n",
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batostr(&bt_sk(sk)->src), batostr(&bt_sk(sk)->dst),
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sk->sk_state, rfcomm_pi(sk)->channel);
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size -= len;
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if (size <= 0)
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break;
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str += len;
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}
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read_unlock_bh(&rfcomm_sk_list.lock);
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@ -960,13 +960,22 @@ static ssize_t sco_sysfs_show(struct class *dev,
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struct sock *sk;
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struct hlist_node *node;
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char *str = buf;
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int size = PAGE_SIZE;
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read_lock_bh(&sco_sk_list.lock);
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sk_for_each(sk, node, &sco_sk_list.head) {
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str += sprintf(str, "%s %s %d\n",
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int len;
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len = snprintf(str, size, "%s %s %d\n",
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batostr(&bt_sk(sk)->src), batostr(&bt_sk(sk)->dst),
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sk->sk_state);
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size -= len;
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if (size <= 0)
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break;
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str += len;
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}
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read_unlock_bh(&sco_sk_list.lock);
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