Commit deb4cd8b authored by Darrick J. Wong's avatar Darrick J. Wong
Browse files

xfs: transfer recovered intent item ownership in ->iop_recover 



Now that we pass the xfs_defer_pending object into the intent item
recovery functions, we know exactly when ownership of the sole refcount
passes from the recovery context to the intent done item.  At that
point, we need to null out dfp_intent so that the recovery mechanism
won't release it.  This should fix the UAF problem reported by Long Li.

Note that we still want to recreate the full deferred work state.  That
will be addressed in the next patches.

Fixes: 2e76f188 ("xfs: cancel intents immediately if process_intents fails")
Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
parent a050acdf

fs/xfs/libxfs/xfs_log_recover.h

+2 −0
Original line number Diff line number Diff line
@@ -155,5 +155,7 @@ xlog_recover_resv(const struct xfs_trans_res *r) 


void xlog_recover_intent_item(struct xlog *log, struct xfs_log_item *lip,

		xfs_lsn_t lsn, unsigned int dfp_type);

void xlog_recover_transfer_intent(struct xfs_trans *tp,

		struct xfs_defer_pending *dfp);



#endif	/* __XFS_LOG_RECOVER_H__ */

fs/xfs/xfs_attr_item.c

+1 −0
Original line number Diff line number Diff line
@@ -632,6 +632,7 @@ xfs_attri_item_recover( 


	args->trans = tp;

	done_item = xfs_trans_get_attrd(tp, attrip);

	xlog_recover_transfer_intent(tp, dfp);



	xfs_ilock(ip, XFS_ILOCK_EXCL);

	xfs_trans_ijoin(tp, ip, 0);

fs/xfs/xfs_bmap_item.c

+2 −0
Original line number Diff line number Diff line
@@ -524,6 +524,8 @@ xfs_bui_item_recover( 
		goto err_rele;



	budp = xfs_trans_get_bud(tp, buip);

	xlog_recover_transfer_intent(tp, dfp);



	xfs_ilock(ip, XFS_ILOCK_EXCL);

	xfs_trans_ijoin(tp, ip, 0);

fs/xfs/xfs_extfree_item.c

+2 −0
Original line number Diff line number Diff line
@@ -689,7 +689,9 @@ xfs_efi_item_recover( 
	error = xfs_trans_alloc(mp, &resv, 0, 0, 0, &tp);

	if (error)

		return error;



	efdp = xfs_trans_get_efd(tp, efip, efip->efi_format.efi_nextents);

	xlog_recover_transfer_intent(tp, dfp);



	for (i = 0; i < efip->efi_format.efi_nextents; i++) {

		struct xfs_extent_free_item	fake = {

fs/xfs/xfs_log_recover.c

+12 −7
Original line number Diff line number Diff line
@@ -2590,13 +2590,6 @@ xlog_recover_process_intents( 
			break;

		}



		/*

		 * XXX: @lip could have been freed, so detach the log item from

		 * the pending item before freeing the pending item.  This does

		 * not fix the existing UAF bug that occurs if ->iop_recover

		 * fails after creating the intent done item.

		 */

		dfp->dfp_intent = NULL;

		xfs_defer_cancel_recovery(log->l_mp, dfp);

	}

	if (error)
@@ -2630,6 +2623,18 @@ xlog_recover_cancel_intents( 
	}

}



/*

 * Transfer ownership of the recovered log intent item to the recovery

 * transaction.

 */

void

xlog_recover_transfer_intent(

	struct xfs_trans		*tp,

	struct xfs_defer_pending	*dfp)

{

	dfp->dfp_intent = NULL;

}



/*

 * This routine performs a transaction to null out a bad inode pointer

 * in an agi unlinked inode hash bucket.