CVE-2023-52803 SUNRPC: Fix RPC client cleaned up the freed pipefs dentries

2024-05-2115:31:15

Linux

github.com

sunrpc

vulnerability resolved

pipefs dentries

separated workqueue

special scenarios

kernel frees

misjudge

kasan

slab-use-after-free

dget_parent

rpc_remove_pipedir

rpc_free_client_work

6.6 Medium

AI Score

Confidence

Low

0.0004 Low

EPSS

Percentile

10.4%

JSON

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

SUNRPC: Fix RPC client cleaned up the freed pipefs dentries

RPC client pipefs dentries cleanup is in separated rpc_remove_pipedir()
workqueue,which takes care about pipefs superblock locking.
In some special scenarios, when kernel frees the pipefs sb of the
current client and immediately alloctes a new pipefs sb,
rpc_remove_pipedir function would misjudge the existence of pipefs
sb which is not the one it used to hold. As a result,
the rpc_remove_pipedir would clean the released freed pipefs dentries.

To fix this issue, rpc_remove_pipedir should check whether the
current pipefs sb is consistent with the original pipefs sb.

This error can be catched by KASAN:

[ 250.497700] BUG: KASAN: slab-use-after-free in dget_parent+0x195/0x200
[ 250.498315] Read of size 4 at addr ffff88800a2ab804 by task kworker/0:18/106503
[ 250.500549] Workqueue: events rpc_free_client_work
[ 250.501001] Call Trace:
[ 250.502880] kasan_report+0xb6/0xf0
[ 250.503209] ? dget_parent+0x195/0x200
[ 250.503561] dget_parent+0x195/0x200
[ 250.503897] ? __pfx_rpc_clntdir_depopulate+0x10/0x10
[ 250.504384] rpc_rmdir_depopulate+0x1b/0x90
[ 250.504781] rpc_remove_client_dir+0xf5/0x150
[ 250.505195] rpc_free_client_work+0xe4/0x230
[ 250.505598] process_one_work+0x8ee/0x13b0
…
[ 22.039056] Allocated by task 244:
[ 22.039390] kasan_save_stack+0x22/0x50
[ 22.039758] kasan_set_track+0x25/0x30
[ 22.040109] __kasan_slab_alloc+0x59/0x70
[ 22.040487] kmem_cache_alloc_lru+0xf0/0x240
[ 22.040889] __d_alloc+0x31/0x8e0
[ 22.041207] d_alloc+0x44/0x1f0
[ 22.041514] __rpc_lookup_create_exclusive+0x11c/0x140
[ 22.041987] rpc_mkdir_populate.constprop.0+0x5f/0x110
[ 22.042459] rpc_create_client_dir+0x34/0x150
[ 22.042874] rpc_setup_pipedir_sb+0x102/0x1c0
[ 22.043284] rpc_client_register+0x136/0x4e0
[ 22.043689] rpc_new_client+0x911/0x1020
[ 22.044057] rpc_create_xprt+0xcb/0x370
[ 22.044417] rpc_create+0x36b/0x6c0
…
[ 22.049524] Freed by task 0:
[ 22.049803] kasan_save_stack+0x22/0x50
[ 22.050165] kasan_set_track+0x25/0x30
[ 22.050520] kasan_save_free_info+0x2b/0x50
[ 22.050921] __kasan_slab_free+0x10e/0x1a0
[ 22.051306] kmem_cache_free+0xa5/0x390
[ 22.051667] rcu_core+0x62c/0x1930
[ 22.051995] __do_softirq+0x165/0x52a
[ 22.052347]
[ 22.052503] Last potentially related work creation:
[ 22.052952] kasan_save_stack+0x22/0x50
[ 22.053313] __kasan_record_aux_stack+0x8e/0xa0
[ 22.053739] __call_rcu_common.constprop.0+0x6b/0x8b0
[ 22.054209] dentry_free+0xb2/0x140
[ 22.054540] __dentry_kill+0x3be/0x540
[ 22.054900] shrink_dentry_list+0x199/0x510
[ 22.055293] shrink_dcache_parent+0x190/0x240
[ 22.055703] do_one_tree+0x11/0x40
[ 22.056028] shrink_dcache_for_umount+0x61/0x140
[ 22.056461] generic_shutdown_super+0x70/0x590
[ 22.056879] kill_anon_super+0x3a/0x60
[ 22.057234] rpc_kill_sb+0x121/0x200

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "include/linux/sunrpc/clnt.h",
      "net/sunrpc/clnt.c"
    ],
    "versions": [
      {
        "version": "0157d021d23a",
        "lessThan": "dedf2a0eb944",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "0157d021d23a",
        "lessThan": "194454afa6aa",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "0157d021d23a",
        "lessThan": "7749fd2dbef7",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "0157d021d23a",
        "lessThan": "1cdb52ffd660",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "0157d021d23a",
        "lessThan": "cc2e7ebbeb1d",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "0157d021d23a",
        "lessThan": "bfca5fb4e97c",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "include/linux/sunrpc/clnt.h",
      "net/sunrpc/clnt.c"
    ],
    "versions": [
      {
        "version": "3.4",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "3.4",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.10.202",
        "lessThanOrEqual": "5.10.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.15.140",
        "lessThanOrEqual": "5.15.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.1.64",
        "lessThanOrEqual": "6.1.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.5.13",
        "lessThanOrEqual": "6.5.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.6.3",
        "lessThanOrEqual": "6.6.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.7",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]