Bug 2422714 (CVE-2025-68229)

Summary: CVE-2025-68229 kernel: scsi: target: tcm_loop: Fix segfault in tcm_loop_tpg_address_show()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: medium    
Version: unspecifiedKeywords: Security
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OS: Linux   
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A null pointer dereference was found in the SCSI target tcm_loop driver in the Linux kernel. If scsi_host allocation fails during tcm_loop_driver_probe(), the tl_hba->sh pointer remains NULL. Subsequent reads of the tpg_address configfs attribute trigger a segfault when dereferencing this NULL pointer.
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Description OSIDB Bzimport 2025-12-16 14:05:50 UTC 
In the Linux kernel, the following vulnerability has been resolved:

scsi: target: tcm_loop: Fix segfault in tcm_loop_tpg_address_show()

If the allocation of tl_hba->sh fails in tcm_loop_driver_probe() and we
attempt to dereference it in tcm_loop_tpg_address_show() we will get a
segfault, see below for an example. So, check tl_hba->sh before
dereferencing it.

  Unable to allocate struct scsi_host
  BUG: kernel NULL pointer dereference, address: 0000000000000194
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  PGD 0 P4D 0
  Oops: 0000 [#1] PREEMPT SMP NOPTI
  CPU: 1 PID: 8356 Comm: tokio-runtime-w Not tainted 6.6.104.2-4.azl3 #1
  Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS Hyper-V UEFI Release v4.1 09/28/2024
  RIP: 0010:tcm_loop_tpg_address_show+0x2e/0x50 [tcm_loop]
...
  Call Trace:
   <TASK>
   configfs_read_iter+0x12d/0x1d0 [configfs]
   vfs_read+0x1b5/0x300
   ksys_read+0x6f/0xf0
...
Comment 1 Alexander B 2025-12-17 01:05:58 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025121636-CVE-2025-68229-8958@gregkh/T