CVE-2021-47012 RDMA/siw: Fix a use after free in siw_alloc_mr

2024-02-2808:13:30

Linux

github.com

linux kernel

vulnerability

uaf

siw_alloc_mr

siw_mr_add_mem

kfree

xa_alloc_cyclic

siw_mr_drop_mem

patch

7.2 High

AI Score

Confidence

Low

0.0004 Low

EPSS

Percentile

15.7%

JSON

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

RDMA/siw: Fix a use after free in siw_alloc_mr

Our code analyzer reported a UAF.

In siw_alloc_mr(), it calls siw_mr_add_mem(mr,…). In the implementation of
siw_mr_add_mem(), mem is assigned to mr->mem and then mem is freed via
kfree(mem) if xa_alloc_cyclic() failed. Here, mr->mem still point to a
freed object. After, the execution continue up to the err_out branch of
siw_alloc_mr, and the freed mr->mem is used in siw_mr_drop_mem(mr).

My patch moves “mr->mem = mem” behind the if (xa_alloc_cyclic(…)<0) {}
section, to avoid the uaf.

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "drivers/infiniband/sw/siw/siw_mem.c"
    ],
    "versions": [
      {
        "version": "2251334dcac9",
        "lessThan": "30b9e92d0b5e",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "2251334dcac9",
        "lessThan": "608a4b90ece0",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "2251334dcac9",
        "lessThan": "3e22b88e02c1",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "2251334dcac9",
        "lessThan": "ad9ce7188432",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "2251334dcac9",
        "lessThan": "3093ee182f01",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "drivers/infiniband/sw/siw/siw_mem.c"
    ],
    "versions": [
      {
        "version": "5.3",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "5.3",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.4.119",
        "lessThanOrEqual": "5.4.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.10.37",
        "lessThanOrEqual": "5.10.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.11.21",
        "lessThanOrEqual": "5.11.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.12.4",
        "lessThanOrEqual": "5.12.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.13",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]