Commit 89076b5a authored by Matthew Auld's avatar Matthew Auld
Browse files

drm/xe: prevent potential UAF in pf_provision_vf_ggtt() 



The node ptr can point to an already freed ptr, if we hit the path with
an already allocated node. We later dereference that pointer with:

	xe_gt_assert(gt, !xe_ggtt_node_allocated(node));

which is a potential UAF. Fix this by not stashing the ptr for node.
Also since it is likely a bad idea to leave config->ggtt_region pointing
to a stale ptr, also set that to NULL by calling
pf_release_vf_config_ggtt() instead of pf_release_ggtt().

Fixes: 34e80422 ("drm/xe: Make xe_ggtt_node struct independent")
Signed-off-by: default avatarMatthew Auld <matthew.auld@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240828104341.180111-2-matthew.auld@intel.com
parent cd89de14

drivers/gpu/drm/xe/xe_gt_sriov_pf_config.c

+4 −4
Original line number Diff line number Diff line
@@ -399,7 +399,7 @@ static void pf_release_vf_config_ggtt(struct xe_gt *gt, struct xe_gt_sriov_confi 
static int pf_provision_vf_ggtt(struct xe_gt *gt, unsigned int vfid, u64 size)

{

	struct xe_gt_sriov_config *config = pf_pick_vf_config(gt, vfid);

	struct xe_ggtt_node *node = config->ggtt_region;

	struct xe_ggtt_node *node;

	struct xe_tile *tile = gt_to_tile(gt);

	struct xe_ggtt *ggtt = tile->mem.ggtt;

	u64 alignment = pf_get_ggtt_alignment(gt);
@@ -411,14 +411,14 @@ static int pf_provision_vf_ggtt(struct xe_gt *gt, unsigned int vfid, u64 size) 


	size = round_up(size, alignment);



	if (xe_ggtt_node_allocated(node)) {

	if (xe_ggtt_node_allocated(config->ggtt_region)) {

		err = pf_distribute_config_ggtt(tile, vfid, 0, 0);

		if (unlikely(err))

			return err;



		pf_release_ggtt(tile, node);

		pf_release_vf_config_ggtt(gt, config);

	}

	xe_gt_assert(gt, !xe_ggtt_node_allocated(node));

	xe_gt_assert(gt, !xe_ggtt_node_allocated(config->ggtt_region));



	if (!size)

		return 0;