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[Bluetooth] Fix L2CAP and HCI setsockopt() information leaks

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The L2CAP and HCI setsockopt() implementations have a small information
leak that makes it possible to leak kernel stack memory to userspace.

If the optlen parameter is 0, no data will be copied by copy_from_user(),
but the uninitialized stack buffer will be read and stored later. A call
to getsockopt() can now retrieve the leaked information.

To fix this problem the stack buffer given to copy_from_user() must be
initialized with the current settings.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
This commit is contained in:
Marcel Holtmann 2007-05-05 00:35:59 +02:00
parent dc87c3985e
commit 0878b6667f
2 changed files with 15 additions and 0 deletions
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9
net/bluetooth/hci_sock.c
View file

@ -499,6 +499,15 @@ static int hci_sock_setsockopt(struct socket *sock, int level, int optname, char
break;
case HCI_FILTER:
{
struct hci_filter *f = &hci_pi(sk)->filter;
uf.type_mask = f->type_mask;
uf.opcode = f->opcode;
uf.event_mask[0] = *((u32 *) f->event_mask + 0);
uf.event_mask[1] = *((u32 *) f->event_mask + 1);
}
len = min_t(unsigned int, len, sizeof(uf));
if (copy_from_user(&uf, optval, len)) {
err = -EFAULT;

6
net/bluetooth/l2cap.c
View file

@ -954,11 +954,17 @@ static int l2cap_sock_setsockopt(struct socket *sock, int level, int optname, ch
switch (optname) {
case L2CAP_OPTIONS:
opts.imtu = l2cap_pi(sk)->imtu;
opts.omtu = l2cap_pi(sk)->omtu;
opts.flush_to = l2cap_pi(sk)->flush_to;
opts.mode = 0x00;
len = min_t(unsigned int, sizeof(opts), optlen);
if (copy_from_user((char *) &opts, optval, len)) {
err = -EFAULT;
break;
}
l2cap_pi(sk)->imtu = opts.imtu;
l2cap_pi(sk)->omtu = opts.omtu;
break;