On Tue, Nov 3, 2020 at 1:41 AM Magnus Karlsson
<magnus.karlsson@xxxxxxxxx> wrote:
>
> From: Magnus Karlsson <magnus.karlsson@xxxxxxxxx>
>
> Fix a possible null pointer dereference in xsk_socket__delete that
> will occur if a null pointer is fed into the function.
>
> Fixes: 2f6324a3937f ("libbpf: Support shared umems between queues and devices")
> Reported-by: Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx>
> Signed-off-by: Magnus Karlsson <magnus.karlsson@xxxxxxxxx>
> ---
Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
> tools/lib/bpf/xsk.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c
> index e3c98c0..504b7a8 100644
> --- a/tools/lib/bpf/xsk.c
> +++ b/tools/lib/bpf/xsk.c
> @@ -891,13 +891,14 @@ int xsk_umem__delete(struct xsk_umem *umem)
> void xsk_socket__delete(struct xsk_socket *xsk)
> {
> size_t desc_sz = sizeof(struct xdp_desc);
> - struct xsk_ctx *ctx = xsk->ctx;
> struct xdp_mmap_offsets off;
> + struct xsk_ctx *ctx;
> int err;
>
> if (!xsk)
> return;
>
> + ctx = xsk->ctx;
> if (ctx->prog_fd != -1) {
> xsk_delete_bpf_maps(xsk);
> close(ctx->prog_fd);
> --
> 2.7.4
>
