Hi Norbert,
On Sun, Jun 20, 2021 at 02:38:42PM +0200, Norbert Slusarek wrote:
> If optval != NULL and optlen = 0 are specified for SO_J1939_FILTER in
> j1939_sk_setsockopt(), memdup_sockptr() will return ZERO_PTR for 0 size
> allocation. The new filter will be mistakenly assigned ZERO_PTR.
> This patch checks for optlen != 0 and filter will be assigned NULL
> in case of optlen = 0.
>
> Fixes: a7b75c5a8c41 ("net: pass a sockptr_t into ->setsockopt")
> Signed-off-by: Norbert Slusarek <nslusarek@xxxxxxx>
Acked-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
Thank you!
> ---
> net/can/j1939/socket.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/can/j1939/socket.c b/net/can/j1939/socket.c
> index 56aa66147d5a..ff20cb629200 100644
> --- a/net/can/j1939/socket.c
> +++ b/net/can/j1939/socket.c
> @@ -673,7 +673,7 @@ static int j1939_sk_setsockopt(struct socket *sock, int level, int optname,
>
> switch (optname) {
> case SO_J1939_FILTER:
> - if (!sockptr_is_null(optval)) {
> + if (!sockptr_is_null(optval) && optlen != 0) {
> struct j1939_filter *f;
> int c;
>
> --
> 2.30.2
>
>
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