CVE-2025-21739 Information

Description

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

Reference

https://git.kernel.org/stable/c/0c77c0d754fe83cb154715fcfec6c3faef94f207 https://git.kernel.org/stable/c/9c185beae09a3eb85f54777edafa227f7e03075d https://git.kernel.org/stable/c/f8fb2403ddebb5eea0033d90d9daae4c88749ada