decode: check set_sampler_views args

Fix found thanks to american fuzzy lop.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>

src/vrend_decode.c

@@ -275,6 +275,14 @@ static int vrend_decode_set_sampler_views(struct vrend_decode_ctx *ctx, uint16_t
    num_samps = length - 2;
    shader_type = get_buf_entry(ctx, VIRGL_SET_SAMPLER_VIEWS_SHADER_TYPE);
    start_slot = get_buf_entry(ctx, VIRGL_SET_SAMPLER_VIEWS_START_SLOT);
+
+   if (shader_type >= PIPE_SHADER_TYPES)
+      return EINVAL;
+
+   if (num_samps > PIPE_MAX_SHADER_SAMPLER_VIEWS ||
+       start_slot > (PIPE_MAX_SHADER_SAMPLER_VIEWS - num_samps))
+      return EINVAL;
+
    for (i = 0; i < num_samps; i++) {
       uint32_t handle = get_buf_entry(ctx, VIRGL_SET_SAMPLER_VIEWS_V0_HANDLE + i);
       vrend_set_single_sampler_view(ctx->grctx, shader_type, i + start_slot, handle);