scsi: ufs: core: Fix use-after free in init error and remove paths

devm_blk_crypto_profile_init() registers a cleanup handler to run when
the associated (platform-) device is being released. For UFS, the
crypto private data and pointers are stored as part of the ufs_hba's
data structure 'struct ufs_hba::crypto_profile'. This structure is
allocated as part of the underlying ufshcd and therefore Scsi_host
allocation.

During driver release or during error handling in ufshcd_pltfrm_init(),
this structure is released as part of ufshcd_dealloc_host() before the
(platform-) device associated with the crypto call above is released.
Once this device is released, the crypto cleanup code will run, using
the just-released 'struct ufs_hba::crypto_profile'. This causes a
use-after-free situation:

Call trace:
kfree+0x60/0x2d8 (P)
kvfree+0x44/0x60
blk_crypto_profile_destroy_callback+0x28/0x70
devm_action_release+0x1c/0x30
release_nodes+0x6c/0x108
devres_release_all+0x98/0x100
device_unbind_cleanup+0x20/0x70
really_probe+0x218/0x2d0

In other words, the initialisation code flow is:

platform-device probe
ufshcd_pltfrm_init()
ufshcd_alloc_host()
scsi_host_alloc()
allocation of struct ufs_hba
creation of scsi-host devices
devm_blk_crypto_profile_init()
devm registration of cleanup handler using platform-device

and during error handling of ufshcd_pltfrm_init() or during driver
removal:

ufshcd_dealloc_host()
scsi_host_put()
put_device(scsi-host)
release of struct ufs_hba
put_device(platform-device)
crypto cleanup handler

To fix this use-after free, change ufshcd_alloc_host() to register a
devres action to automatically cleanup the underlying SCSI device on
ufshcd destruction, without requiring explicit calls to
ufshcd_dealloc_host(). This way:

* the crypto profile and all other ufs_hba-owned resources are
destroyed before SCSI (as they've been registered after)
* a memleak is plugged in tc-dwc-g210-pci.c remove() as a
side-effect
* EXPORT_SYMBOL_GPL(ufshcd_dealloc_host) can be removed fully as
it's not needed anymore
* no future drivers using ufshcd_alloc_host() could ever forget
adding the cleanup

Fixes: cb77cb5abe1f ("blk-crypto: rename blk_keyslot_manager to blk_crypto_profile")
Fixes: d76d9d7d1009 ("scsi: ufs: use devm_blk_ksm_init()")
Cc: [e-mail]
Signed-off-by: André Draszik <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Reviewed-by: Bean Huo <[e-mail]>
Reviewed-by: Manivannan Sadhasivam <[e-mail]>
Acked-by: Eric Biggers <[e-mail]>
Signed-off-by: Martin K. Petersen <[e-mail]>

drivers/ufs/core/ufshcd.c

···
 #endif /* CONFIG_PM_SLEEP  */
 
 /**
- * ufshcd_dealloc_host - deallocate Host Bus Adapter (HBA)
- * @hba: pointer to Host Bus Adapter (HBA)
- */
-void ufshcd_dealloc_host(struct ufs_hba *hba)
-{
-	scsi_host_put(hba->host);
-}
-EXPORT_SYMBOL_GPL(ufshcd_dealloc_host);
-
-/**
  * ufshcd_set_dma_mask - Set dma mask based on the controller
  *			 addressing capability
  * @hba: per adapter instance
···
 }
 
 /**
+ * ufshcd_devres_release - devres cleanup handler, invoked during release of
+ *			   hba->dev
+ * @host: pointer to SCSI host
+ */
+static void ufshcd_devres_release(void *host)
+{
+	scsi_host_put(host);
+}
+
+/**
  * ufshcd_alloc_host - allocate Host Bus Adapter (HBA)
  * @dev: pointer to device handle
  * @hba_handle: driver private handle
  *
  * Return: 0 on success, non-zero value on failure.
+ *
+ * NOTE: There is no corresponding ufshcd_dealloc_host() because this function
+ * keeps track of its allocations using devres and deallocates everything on
+ * device removal automatically.
  */
 int ufshcd_alloc_host(struct device *dev, struct ufs_hba **hba_handle)
 {
···
 		err = -ENOMEM;
 		goto out_error;
 	}
+
+	err = devm_add_action_or_reset(dev, ufshcd_devres_release,
+				       host);
+	if (err)
+		return dev_err_probe(dev, err,
+				     "failed to add ufshcd dealloc action\n");
+
 	host->nr_maps = HCTX_TYPE_POLL + 1;
 	hba = shost_priv(host);
 	hba->host = host;

drivers/ufs/host/ufshcd-pci.c

···
 	pm_runtime_forbid(&pdev->dev);
 	pm_runtime_get_noresume(&pdev->dev);
 	ufshcd_remove(hba);
-	ufshcd_dealloc_host(hba);
 }
 
 /**
···
 	err = ufshcd_init(hba, mmio_base, pdev->irq);
 	if (err) {
 		dev_err(&pdev->dev, "Initialization failed\n");
-		ufshcd_dealloc_host(hba);
 		return err;
 	}
 

drivers/ufs/host/ufshcd-pltfrm.c

···
 	struct device *dev = &pdev->dev;
 
 	mmio_base = devm_platform_ioremap_resource(pdev, 0);
-	if (IS_ERR(mmio_base)) {
-		err = PTR_ERR(mmio_base);
-		goto out;
-	}
+	if (IS_ERR(mmio_base))
+		return PTR_ERR(mmio_base);
 
 	irq = platform_get_irq(pdev, 0);
-	if (irq < 0) {
-		err = irq;
-		goto out;
-	}
+	if (irq < 0)
+		return irq;
 
 	err = ufshcd_alloc_host(dev, &hba);
 	if (err) {
 		dev_err(dev, "Allocation failed\n");
-		goto out;
+		return err;
 	}
 
 	hba->vops = vops;
···
 	if (err) {
 		dev_err(dev, "%s: clock parse failed %d\n",
 				__func__, err);
-		goto dealloc_host;
+		return err;
 	}
 	err = ufshcd_parse_regulator_info(hba);
 	if (err) {
 		dev_err(dev, "%s: regulator init failed %d\n",
 				__func__, err);
-		goto dealloc_host;
+		return err;
 	}
 
 	ufshcd_init_lanes_per_dir(hba);
···
 	err = ufshcd_parse_operating_points(hba);
 	if (err) {
 		dev_err(dev, "%s: OPP parse failed %d\n", __func__, err);
-		goto dealloc_host;
+		return err;
 	}
 
 	err = ufshcd_init(hba, mmio_base, irq);
 	if (err) {
 		dev_err_probe(dev, err, "Initialization failed with error %d\n",
 			      err);
-		goto dealloc_host;
+		return err;
 	}
 
 	pm_runtime_set_active(dev);
 	pm_runtime_enable(dev);
 
 	return 0;
-
-dealloc_host:
-	ufshcd_dealloc_host(hba);
-out:
-	return err;
 }
 EXPORT_SYMBOL_GPL(ufshcd_pltfrm_init);
 
···
 
 	pm_runtime_get_sync(&pdev->dev);
 	ufshcd_remove(hba);
-	ufshcd_dealloc_host(hba);
 	pm_runtime_disable(&pdev->dev);
 	pm_runtime_put_noidle(&pdev->dev);
 }

include/ufs/ufshcd.h

···
 void ufshcd_enable_irq(struct ufs_hba *hba);
 void ufshcd_disable_irq(struct ufs_hba *hba);
 int ufshcd_alloc_host(struct device *, struct ufs_hba **);
-void ufshcd_dealloc_host(struct ufs_hba *);
 int ufshcd_hba_enable(struct ufs_hba *hba);
 int ufshcd_init(struct ufs_hba *, void __iomem *, unsigned int);
 int ufshcd_link_recovery(struct ufs_hba *hba);