CVE-2025-21739

In the Linux kernel, the following vulnerability has been resolved:

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

This vulnerability is rated as Moderate severity rather than Important because exploitation requires local access on systems equipped with Universal Flash Storage (UFS) host controllers, and it can only be triggered during device initialization failure or driver removal sequences. UFS hardware is predominantly utilized in specialized embedded and mobile environments, meaning typical enterprise server and cloud deployments of Red Hat Enterprise Linux do not utilize these controllers by default. As a result, successful exploitation is limited to privileged or local attackers capable of triggering hardware probe errors or device unbinding, primarily threatening local system availability or integrity.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.