Bug 1225816 (CVE-2024-36925)

Summary: VUL-0: CVE-2024-36925: kernel: swiotlb: initialise restricted pool list_head when SWIOTLB_DYNAMIC=y
Product: [Novell Products] SUSE Security Incidents Reporter: SMASH SMASH <smash_bz>
Component: IncidentsAssignee: Kernel Bugs <kernel-bugs>
Status: RESOLVED INVALID QA Contact: Security Team bot <security-team>
Severity: Normal    
Priority: P5 - None CC: rfrohl
Version: unspecified   
Target Milestone: ---   
Hardware: Other   
OS: Other   
URL: https://smash.suse.de/issue/408241/
Whiteboard: CVSSv3.1:SUSE:CVE-2024-36925:4.1:(AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H)
Found By: Security Response Team Services Priority:
Business Priority: Blocker: ---
Marketing QA Status: --- IT Deployment: ---

Description SMASH SMASH 2024-06-03 09:20:54 UTC 
In the Linux kernel, the following vulnerability has been resolved:

swiotlb: initialise restricted pool list_head when SWIOTLB_DYNAMIC=y

Using restricted DMA pools (CONFIG_DMA_RESTRICTED_POOL=y) in conjunction
with dynamic SWIOTLB (CONFIG_SWIOTLB_DYNAMIC=y) leads to the following
crash when initialising the restricted pools at boot-time:

  | Unable to handle kernel NULL pointer dereference at virtual address 0000000000000008
  | Internal error: Oops: 0000000096000005 [#1] PREEMPT SMP
  | pc : rmem_swiotlb_device_init+0xfc/0x1ec
  | lr : rmem_swiotlb_device_init+0xf0/0x1ec
  | Call trace:
  |  rmem_swiotlb_device_init+0xfc/0x1ec
  |  of_reserved_mem_device_init_by_idx+0x18c/0x238
  |  of_dma_configure_id+0x31c/0x33c
  |  platform_dma_configure+0x34/0x80

faddr2line reveals that the crash is in the list validation code:

  include/linux/list.h:83
  include/linux/rculist.h:79
  include/linux/rculist.h:106
  kernel/dma/swiotlb.c:306
  kernel/dma/swiotlb.c:1695

because add_mem_pool() is trying to list_add_rcu() to a NULL
'mem->pools'.

Fix the crash by initialising the 'mem->pools' list_head in
rmem_swiotlb_device_init() before calling add_mem_pool().

References:
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2024-36925
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2024/CVE-2024-36925.mbox
https://git.kernel.org/stable/c/f2a6b3ed20f2dea4cb645abc6a73c4595662adca
https://git.kernel.org/stable/c/f62e0fefcdfe2c05ccb1aa80521a69524eea9c84
https://git.kernel.org/stable/c/75961ffb5cb3e5196f19cae7683f35cc88b50800
https://www.cve.org/CVERecord?id=CVE-2024-36925
Comment 1 Robert Frohl 2024-06-03 09:27:42 UTC 
not affected, closing