From 101545f6fef4a0a3ea8daf0b5b880df2c6a92a69 Mon Sep 17 00:00:00 2001 From: Marcel Holtmann Date: Mon, 15 Mar 2010 14:12:58 -0700 Subject: [PATCH] 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 Signed-off-by: Marcel Holtmann --- net/bluetooth/l2cap.c | 10 +++++++++- net/bluetooth/rfcomm/core.c | 13 ++++++++++++- net/bluetooth/rfcomm/sock.c | 11 ++++++++++- net/bluetooth/sco.c | 11 ++++++++++- 4 files changed, 41 insertions(+), 4 deletions(-) diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c index 4db7ae2fe07d..27551820741e 100644 --- a/net/bluetooth/l2cap.c +++ b/net/bluetooth/l2cap.c @@ -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); diff --git a/net/bluetooth/rfcomm/core.c b/net/bluetooth/rfcomm/core.c index db8a68e1a5ba..cf164073269d 100644 --- a/net/bluetooth/rfcomm/core.c +++ b/net/bluetooth/rfcomm/core.c @@ -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(); diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c index ca87d6ac6a20..8d0ee0b8a6b6 100644 --- a/net/bluetooth/rfcomm/sock.c +++ b/net/bluetooth/rfcomm/sock.c @@ -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); diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c index f93b939539bc..967a75175c66 100644 --- a/net/bluetooth/sco.c +++ b/net/bluetooth/sco.c @@ -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); -- 2.30.2