ghsa-vwrr-j6j5-7xgm
Vulnerability from github
Published
2024-05-01 06:31
Modified
2024-10-10 12:31
Details

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

ubifs: ubifs_symlink: Fix memleak of inode->i_link in error path

For error handling path in ubifs_symlink(), inode will be marked as bad first, then iput() is invoked. If inode->i_link is initialized by fscrypt_encrypt_symlink() in encryption scenario, inode->i_link won't be freed by callchain ubifs_free_inode -> fscrypt_free_inode in error handling path, because make_bad_inode() has changed 'inode->i_mode' as 'S_IFREG'. Following kmemleak is easy to be reproduced by injecting error in ubifs_jnl_update() when doing symlink in encryption scenario: unreferenced object 0xffff888103da3d98 (size 8): comm "ln", pid 1692, jiffies 4294914701 (age 12.045s) backtrace: kmemdup+0x32/0x70 __fscrypt_encrypt_symlink+0xed/0x1c0 ubifs_symlink+0x210/0x300 [ubifs] vfs_symlink+0x216/0x360 do_symlinkat+0x11a/0x190 do_syscall_64+0x3b/0xe0 There are two ways fixing it: 1. Remove make_bad_inode() in error handling path. We can do that because ubifs_evict_inode() will do same processes for good symlink inode and bad symlink inode, for inode->i_nlink checking is before is_bad_inode(). 2. Free inode->i_link before marking inode bad. Method 2 is picked, it has less influence, personally, I think.

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{
  "affected": [],
  "aliases": [
    "CVE-2024-26972"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-05-01T06:15:13Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nubifs: ubifs_symlink: Fix memleak of inode-\u003ei_link in error path\n\nFor error handling path in ubifs_symlink(), inode will be marked as\nbad first, then iput() is invoked. If inode-\u003ei_link is initialized by\nfscrypt_encrypt_symlink() in encryption scenario, inode-\u003ei_link won\u0027t\nbe freed by callchain ubifs_free_inode -\u003e fscrypt_free_inode in error\nhandling path, because make_bad_inode() has changed \u0027inode-\u003ei_mode\u0027 as\n\u0027S_IFREG\u0027.\nFollowing kmemleak is easy to be reproduced by injecting error in\nubifs_jnl_update() when doing symlink in encryption scenario:\n unreferenced object 0xffff888103da3d98 (size 8):\n  comm \"ln\", pid 1692, jiffies 4294914701 (age 12.045s)\n  backtrace:\n   kmemdup+0x32/0x70\n   __fscrypt_encrypt_symlink+0xed/0x1c0\n   ubifs_symlink+0x210/0x300 [ubifs]\n   vfs_symlink+0x216/0x360\n   do_symlinkat+0x11a/0x190\n   do_syscall_64+0x3b/0xe0\nThere are two ways fixing it:\n 1. Remove make_bad_inode() in error handling path. We can do that\n    because ubifs_evict_inode() will do same processes for good\n    symlink inode and bad symlink inode, for inode-\u003ei_nlink checking\n    is before is_bad_inode().\n 2. Free inode-\u003ei_link before marking inode bad.\nMethod 2 is picked, it has less influence, personally, I think.",
  "id": "GHSA-vwrr-j6j5-7xgm",
  "modified": "2024-10-10T12:31:11Z",
  "published": "2024-05-01T06:31:42Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-26972"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3faea7810e2b3e9a9a92ef42d7e5feaeb8ff7133"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/62b5ae00c2b835639002ce898ccb5d82c51073ae"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6379b44cdcd67f5f5d986b73953e99700591edfa"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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