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authorMarcel Holtmann <marcel@holtmann.org>2010-03-15 14:12:58 -0700
committerMarcel Holtmann <marcel@holtmann.org>2010-03-21 05:49:32 +0100
commit101545f6fef4a0a3ea8daf0b5b880df2c6a92a69 (patch)
tree5b4254a64db65f1958a36ec6955dbba1b71031a7 /net/bluetooth/rfcomm/core.c
parentaf98441397227a5a4f212cd48710eea72a14dbdb (diff)
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>
Diffstat (limited to 'net/bluetooth/rfcomm/core.c')
-rw-r--r--net/bluetooth/rfcomm/core.c13
1 files changed, 12 insertions, 1 deletions
diff --git a/net/bluetooth/rfcomm/core.c b/net/bluetooth/rfcomm/core.c
index db8a68e1a5b..cf164073269 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();