[PATCH v2] Bluetooth: ISO: Fix info leak in iso_sock_getsockopt()

[PATCH v2] Bluetooth: ISO: Fix info leak in iso_sock_getsockopt()

[Luiz Augusto von Dentz]

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

The C standard rules for when struct holes are zeroed out are slightly
weird.  The existing assignments might initialize everything, but GCC
is allowed to (and does sometimes) leave the struct holes uninitialized,
so instead of using yet another variable and copy the QoS settings just
use a pointer to the stored QoS settings.

Fixes: ccf74f2390d6 ("Bluetooth: Add BTPROTO_ISO socket type")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
---
v2: Fix author

 net/bluetooth/iso.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/net/bluetooth/iso.c b/net/bluetooth/iso.c
index 19d003727b50..dded22cde0d1 100644
--- a/net/bluetooth/iso.c
+++ b/net/bluetooth/iso.c
@@ -1235,7 +1235,7 @@ static int iso_sock_getsockopt(struct socket *sock, int level, int optname,
 {
 	struct sock *sk = sock->sk;
 	int len, err = 0;
-	struct bt_iso_qos qos;
+	struct bt_iso_qos *qos;
 	u8 base_len;
 	u8 *base;
 
@@ -1261,12 +1261,12 @@ static int iso_sock_getsockopt(struct socket *sock, int level, int optname,
 
 	case BT_ISO_QOS:
 		if (sk->sk_state == BT_CONNECTED || sk->sk_state == BT_CONNECT2)
-			qos = iso_pi(sk)->conn->hcon->iso_qos;
+			qos = &iso_pi(sk)->conn->hcon->iso_qos;
 		else
-			qos = iso_pi(sk)->qos;
+			qos = &iso_pi(sk)->qos;
 
-		len = min_t(unsigned int, len, sizeof(qos));
-		if (copy_to_user(optval, (char *)&qos, len))
+		len = min_t(unsigned int, len, sizeof(*qos));
+		if (copy_to_user(optval, qos, len))
 			err = -EFAULT;
 
 		break;
-- 
2.37.1

Re: [PATCH v2] Bluetooth: ISO: Fix info leak in iso_sock_getsockopt()

[patchwork-bot+bluetooth]

Hello:

This patch was applied to bluetooth/bluetooth-next.git (master)
by Luiz Augusto von Dentz <luiz.von.dentz@intel.com>:

On Thu, 28 Jul 2022 16:51:30 -0700 you wrote:
> From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
> 
> The C standard rules for when struct holes are zeroed out are slightly
> weird.  The existing assignments might initialize everything, but GCC
> is allowed to (and does sometimes) leave the struct holes uninitialized,
> so instead of using yet another variable and copy the QoS settings just
> use a pointer to the stored QoS settings.
> 
> [...]

Here is the summary with links:
  - [v2] Bluetooth: ISO: Fix info leak in iso_sock_getsockopt()
    https://git.kernel.org/bluetooth/bluetooth-next/c/2cd0542726ba

You are awesome, thank you!
-- 
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