FKIE_CVE-2022-50751

Vulnerability from fkie_nvd - Published: 2025-12-24 13:16 - Updated: 2025-12-24 13:16
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: configfs: fix possible memory leak in configfs_create_dir() kmemleak reported memory leaks in configfs_create_dir(): unreferenced object 0xffff888009f6af00 (size 192): comm "modprobe", pid 3777, jiffies 4295537735 (age 233.784s) backtrace: kmem_cache_alloc (mm/slub.c:3250 mm/slub.c:3256 mm/slub.c:3263 mm/slub.c:3273) new_fragment (./include/linux/slab.h:600 fs/configfs/dir.c:163) configfs_register_subsystem (fs/configfs/dir.c:1857) basic_write (drivers/hwtracing/stm/p_basic.c:14) stm_p_basic do_one_initcall (init/main.c:1296) do_init_module (kernel/module/main.c:2455) ... unreferenced object 0xffff888003ba7180 (size 96): comm "modprobe", pid 3777, jiffies 4295537735 (age 233.784s) backtrace: kmem_cache_alloc (mm/slub.c:3250 mm/slub.c:3256 mm/slub.c:3263 mm/slub.c:3273) configfs_new_dirent (./include/linux/slab.h:723 fs/configfs/dir.c:194) configfs_make_dirent (fs/configfs/dir.c:248) configfs_create_dir (fs/configfs/dir.c:296) configfs_attach_group.isra.28 (fs/configfs/dir.c:816 fs/configfs/dir.c:852) configfs_register_subsystem (fs/configfs/dir.c:1881) basic_write (drivers/hwtracing/stm/p_basic.c:14) stm_p_basic do_one_initcall (init/main.c:1296) do_init_module (kernel/module/main.c:2455) ... This is because the refcount is not correct in configfs_make_dirent(). For normal stage, the refcount is changing as: configfs_register_subsystem() configfs_create_dir() configfs_make_dirent() configfs_new_dirent() # set s_count = 1 dentry->d_fsdata = configfs_get(sd); # s_count = 2 ... configfs_unregister_subsystem() configfs_remove_dir() remove_dir() configfs_remove_dirent() # s_count = 1 dput() ... *dentry_unlink_inode()* configfs_d_iput() # s_count = 0, release However, if we failed in configfs_create(): configfs_register_subsystem() configfs_create_dir() configfs_make_dirent() # s_count = 2 ... configfs_create() # fail ->out_remove: configfs_remove_dirent(dentry) configfs_put(sd) # s_count = 1 return PTR_ERR(inode); There is no inode in the error path, so the configfs_d_iput() is lost and makes sd and fragment memory leaked. To fix this, when we failed in configfs_create(), manually call configfs_put(sd) to keep the refcount correct.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/07f82dca112262b169bec0001378126439cab776
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/74ac7c9ee2d486c501e7864c903f5098fc477acd
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8bc77754224a2c8581727ffe2e958119b4e27c8f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/90c38f57a821499391526b15cc944c265bd24e48
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c65234b283a65cfbfc94619655e820a5e55199eb
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c72eb6e6e49a71f7598740786568fafdd013a227
Impacted products
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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nconfigfs: fix possible memory leak in configfs_create_dir()\n\nkmemleak reported memory leaks in configfs_create_dir():\n\nunreferenced object 0xffff888009f6af00 (size 192):\n  comm \"modprobe\", pid 3777, jiffies 4295537735 (age 233.784s)\n  backtrace:\n    kmem_cache_alloc (mm/slub.c:3250 mm/slub.c:3256 mm/slub.c:3263 mm/slub.c:3273)\n    new_fragment (./include/linux/slab.h:600 fs/configfs/dir.c:163)\n    configfs_register_subsystem (fs/configfs/dir.c:1857)\n    basic_write (drivers/hwtracing/stm/p_basic.c:14) stm_p_basic\n    do_one_initcall (init/main.c:1296)\n    do_init_module (kernel/module/main.c:2455)\n    ...\n\nunreferenced object 0xffff888003ba7180 (size 96):\n  comm \"modprobe\", pid 3777, jiffies 4295537735 (age 233.784s)\n  backtrace:\n    kmem_cache_alloc (mm/slub.c:3250 mm/slub.c:3256 mm/slub.c:3263 mm/slub.c:3273)\n    configfs_new_dirent (./include/linux/slab.h:723 fs/configfs/dir.c:194)\n    configfs_make_dirent (fs/configfs/dir.c:248)\n    configfs_create_dir (fs/configfs/dir.c:296)\n    configfs_attach_group.isra.28 (fs/configfs/dir.c:816 fs/configfs/dir.c:852)\n    configfs_register_subsystem (fs/configfs/dir.c:1881)\n    basic_write (drivers/hwtracing/stm/p_basic.c:14) stm_p_basic\n    do_one_initcall (init/main.c:1296)\n    do_init_module (kernel/module/main.c:2455)\n    ...\n\nThis is because the refcount is not correct in configfs_make_dirent().\nFor normal stage, the refcount is changing as:\n\nconfigfs_register_subsystem()\n  configfs_create_dir()\n    configfs_make_dirent()\n      configfs_new_dirent() # set s_count = 1\n      dentry-\u003ed_fsdata = configfs_get(sd); # s_count = 2\n...\nconfigfs_unregister_subsystem()\n  configfs_remove_dir()\n    remove_dir()\n      configfs_remove_dirent() # s_count = 1\n    dput() ...\n      *dentry_unlink_inode()*\n        configfs_d_iput() # s_count = 0, release\n\nHowever, if we failed in configfs_create():\n\nconfigfs_register_subsystem()\n  configfs_create_dir()\n    configfs_make_dirent() # s_count = 2\n    ...\n    configfs_create() # fail\n    -\u003eout_remove:\n    configfs_remove_dirent(dentry)\n      configfs_put(sd) # s_count = 1\n      return PTR_ERR(inode);\n\nThere is no inode in the error path, so the configfs_d_iput() is lost\nand makes sd and fragment memory leaked.\n\nTo fix this, when we failed in configfs_create(), manually call\nconfigfs_put(sd) to keep the refcount correct."
    }
  ],
  "id": "CVE-2022-50751",
  "lastModified": "2025-12-24T13:16:01.823",
  "metrics": {},
  "published": "2025-12-24T13:16:01.823",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/07f82dca112262b169bec0001378126439cab776"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/74ac7c9ee2d486c501e7864c903f5098fc477acd"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8bc77754224a2c8581727ffe2e958119b4e27c8f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/90c38f57a821499391526b15cc944c265bd24e48"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c65234b283a65cfbfc94619655e820a5e55199eb"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c72eb6e6e49a71f7598740786568fafdd013a227"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}


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