Bluetooth: fix oob in rfcomm_sock_setsockopt

[PATCH] Bluetooth: fix oob in rfcomm_sock_setsockopt

Posted by Edward Adam Davis 1 year, 10 months ago

If optlen < sizeof(u32) it will trigger oob, so take the min of them.

Reported-by: syzbot+d4ecae01a53fd9b42e7d@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
---
 net/bluetooth/rfcomm/sock.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c
index b54e8a530f55..42c55c756b51 100644
--- a/net/bluetooth/rfcomm/sock.c
+++ b/net/bluetooth/rfcomm/sock.c
@@ -629,7 +629,7 @@ static int rfcomm_sock_setsockopt_old(struct socket *sock, int optname,
 
 	switch (optname) {
 	case RFCOMM_LM:
-		if (copy_from_sockptr(&opt, optval, sizeof(u32))) {
+		if (copy_from_sockptr(&opt, optval, min_t(int, sizeof(u32), optlen))) {
 			err = -EFAULT;
 			break;
 		}
-- 
2.43.0

Re: [PATCH] Bluetooth: fix oob in rfcomm_sock_setsockopt

Posted by Luiz Augusto von Dentz 1 year, 10 months ago

Hi Edward,

On Tue, Apr 9, 2024 at 9:36 AM Edward Adam Davis <eadavis@qq.com> wrote:
>
> If optlen < sizeof(u32) it will trigger oob, so take the min of them.
>
> Reported-by: syzbot+d4ecae01a53fd9b42e7d@syzkaller.appspotmail.com
> Signed-off-by: Edward Adam Davis <eadavis@qq.com>
> ---
>  net/bluetooth/rfcomm/sock.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c
> index b54e8a530f55..42c55c756b51 100644
> --- a/net/bluetooth/rfcomm/sock.c
> +++ b/net/bluetooth/rfcomm/sock.c
> @@ -629,7 +629,7 @@ static int rfcomm_sock_setsockopt_old(struct socket *sock, int optname,
>
>         switch (optname) {
>         case RFCOMM_LM:
> -               if (copy_from_sockptr(&opt, optval, sizeof(u32))) {
> +               if (copy_from_sockptr(&opt, optval, min_t(int, sizeof(u32), optlen))) {
>                         err = -EFAULT;
>                         break;
>                 }
> --
> 2.43.0

This has been dealt with already:

https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next.git/commit/?id=ee77912bc0bbd78fceb785a81cc9108fa954982f


-- 
Luiz Augusto von Dentz