nvkm_control_mthd_pstate_attr() looks up the pstate at the index supplied by userspace by walking clk->states, and then keeps using the list_for_each_entry cursor after the loop. This is not triggerable today: the function already rejects args->v0.state >= clk->state_nr before the loop, and clk->state_nr is kept in sync with the number of entries on clk->states, so the lookup always breaks on a real entry.
Should the loop ever run to completion, the cursor would point at the list head rather than at a pstate, and the pstate->base.domain[] read and the walk of pstate->list that follow would read past it. Rather than leave that trap in place, track whether the entry was found and return -EINVAL if it was not, like the other lookup failures in this function. No functional change. Signed-off-by: Francesco Magazzu <[email protected]> --- drivers/gpu/drm/nouveau/nvkm/engine/device/ctrl.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/device/ctrl.c b/drivers/gpu/drm/nouveau/nvkm/engine/device/ctrl.c index f2e9a0626..28702741a 100644 --- a/drivers/gpu/drm/nouveau/nvkm/engine/device/ctrl.c +++ b/drivers/gpu/drm/nouveau/nvkm/engine/device/ctrl.c @@ -74,6 +74,7 @@ nvkm_control_mthd_pstate_attr(struct nvkm_control *ctrl, void *data, u32 size) const struct nvkm_domain *domain; struct nvkm_pstate *pstate; struct nvkm_cstate *cstate; + bool found = false; int i = 0, j = -1; u32 lo, hi; int ret = -ENOSYS; @@ -104,10 +105,15 @@ nvkm_control_mthd_pstate_attr(struct nvkm_control *ctrl, void *data, u32 size) if (args->v0.state != NVIF_CONTROL_PSTATE_ATTR_V0_STATE_CURRENT) { list_for_each_entry(pstate, &clk->states, head) { - if (i++ == args->v0.state) + if (i++ == args->v0.state) { + found = true; break; + } } + if (!found) + return -EINVAL; + lo = pstate->base.domain[domain->name]; hi = lo; list_for_each_entry(cstate, &pstate->list, head) { -- 2.55.0
