CVE-2024-36925 swiotlb: initialise restricted pool list_head when SWIOTLB_DYNAMIC=y

2024-05-3015:29:19

Linux

www.cve.org

vulnerability

linux kernel

swiotlb

restricted pool

dynamic swiotlb

crash

dma pools

null pointer dereference

rculist

list validation

add_mem_pool

6.3 Medium

AI Score

Confidence

Low

0.0004 Low

EPSS

Percentile

5.1%

JSON

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().

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "kernel/dma/swiotlb.c"
    ],
    "versions": [
      {
        "version": "1aaa736815eb",
        "lessThan": "f2a6b3ed20f2",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "1aaa736815eb",
        "lessThan": "f62e0fefcdfe",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "1aaa736815eb",
        "lessThan": "75961ffb5cb3",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "kernel/dma/swiotlb.c"
    ],
    "versions": [
      {
        "version": "6.6",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "6.6",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.6.31",
        "lessThanOrEqual": "6.6.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.8.10",
        "lessThanOrEqual": "6.8.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.9",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]