GHSA-FW43-F4RV-3FJG

Vulnerability from github – Published: 2025-12-16 15:30 – Updated: 2026-07-30 06:32
VLAI
Details

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

hfs: validate record offset in hfsplus_bmap_alloc

hfsplus_bmap_alloc can trigger a crash if a record offset or length is larger than node_size

[ 15.264282] BUG: KASAN: slab-out-of-bounds in hfsplus_bmap_alloc+0x887/0x8b0 [ 15.265192] Read of size 8 at addr ffff8881085ca188 by task test/183 [ 15.265949] [ 15.266163] CPU: 0 UID: 0 PID: 183 Comm: test Not tainted 6.17.0-rc2-gc17b750b3ad9 #14 PREEMPT(voluntary) [ 15.266165] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 15.266167] Call Trace: [ 15.266168] [ 15.266169] dump_stack_lvl+0x53/0x70 [ 15.266173] print_report+0xd0/0x660 [ 15.266181] kasan_report+0xce/0x100 [ 15.266185] hfsplus_bmap_alloc+0x887/0x8b0 [ 15.266208] hfs_btree_inc_height.isra.0+0xd5/0x7c0 [ 15.266217] hfsplus_brec_insert+0x870/0xb00 [ 15.266222] __hfsplus_ext_write_extent+0x428/0x570 [ 15.266225] __hfsplus_ext_cache_extent+0x5e/0x910 [ 15.266227] hfsplus_ext_read_extent+0x1b2/0x200 [ 15.266233] hfsplus_file_extend+0x5a7/0x1000 [ 15.266237] hfsplus_get_block+0x12b/0x8c0 [ 15.266238] __block_write_begin_int+0x36b/0x12c0 [ 15.266251] block_write_begin+0x77/0x110 [ 15.266252] cont_write_begin+0x428/0x720 [ 15.266259] hfsplus_write_begin+0x51/0x100 [ 15.266262] cont_write_begin+0x272/0x720 [ 15.266270] hfsplus_write_begin+0x51/0x100 [ 15.266274] generic_perform_write+0x321/0x750 [ 15.266285] generic_file_write_iter+0xc3/0x310 [ 15.266289] __kernel_write_iter+0x2fd/0x800 [ 15.266296] dump_user_range+0x2ea/0x910 [ 15.266301] elf_core_dump+0x2a94/0x2ed0 [ 15.266320] vfs_coredump+0x1d85/0x45e0 [ 15.266349] get_signal+0x12e3/0x1990 [ 15.266357] arch_do_signal_or_restart+0x89/0x580 [ 15.266362] irqentry_exit_to_user_mode+0xab/0x110 [ 15.266364] asm_exc_page_fault+0x26/0x30 [ 15.266366] RIP: 0033:0x41bd35 [ 15.266367] Code: bc d1 f3 0f 7f 27 f3 0f 7f 6f 10 f3 0f 7f 77 20 f3 0f 7f 7f 30 49 83 c0 0f 49 29 d0 48 8d 7c 17 31 e9 9f 0b 00 00 66 0f ef c0 0f 6f 0e f3 0f 6f 56 10 66 0f 74 c1 66 0f d7 d0 49 83 f8f [ 15.266369] RSP: 002b:00007ffc9e62d078 EFLAGS: 00010283 [ 15.266371] RAX: 00007ffc9e62d100 RBX: 0000000000000000 RCX: 0000000000000000 [ 15.266372] RDX: 00000000000000e0 RSI: 0000000000000000 RDI: 00007ffc9e62d100 [ 15.266373] RBP: 0000400000000040 R08: 00000000000000e0 R09: 0000000000000000 [ 15.266374] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 [ 15.266375] R13: 0000000000000000 R14: 0000000000000000 R15: 0000400000000000 [ 15.266376]

When calling hfsplus_bmap_alloc to allocate a free node, this function first retrieves the bitmap from header node and map node using node->page together with the offset and length from hfs_brec_lenoff

len = hfs_brec_lenoff(node, 2, &off16);
off = off16;

off += node->page_offset;
pagep = node->page + (off >> PAGE_SHIFT);
data = kmap_local_page(*pagep);

However, if the retrieved offset or length is invalid(i.e. exceeds node_size), the code may end up accessing pages outside the allocated range for this node.

This patch adds proper validation of both offset and length before use, preventing out-of-bounds page access. Move is_bnode_offset_valid and check_and_correct_requested_length to hfsplus_fs.h, as they may be required by other functions.

Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Show details on source website
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{
  "affected": [],
  "aliases": [
    "CVE-2025-40349"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-12-16T14:15:46Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nhfs: validate record offset in hfsplus_bmap_alloc\n\nhfsplus_bmap_alloc can trigger a crash if a\nrecord offset or length is larger than node_size\n\n[   15.264282] BUG: KASAN: slab-out-of-bounds in hfsplus_bmap_alloc+0x887/0x8b0\n[   15.265192] Read of size 8 at addr ffff8881085ca188 by task test/183\n[   15.265949]\n[   15.266163] CPU: 0 UID: 0 PID: 183 Comm: test Not tainted 6.17.0-rc2-gc17b750b3ad9 #14 PREEMPT(voluntary)\n[   15.266165] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\n[   15.266167] Call Trace:\n[   15.266168]  \u003cTASK\u003e\n[   15.266169]  dump_stack_lvl+0x53/0x70\n[   15.266173]  print_report+0xd0/0x660\n[   15.266181]  kasan_report+0xce/0x100\n[   15.266185]  hfsplus_bmap_alloc+0x887/0x8b0\n[   15.266208]  hfs_btree_inc_height.isra.0+0xd5/0x7c0\n[   15.266217]  hfsplus_brec_insert+0x870/0xb00\n[   15.266222]  __hfsplus_ext_write_extent+0x428/0x570\n[   15.266225]  __hfsplus_ext_cache_extent+0x5e/0x910\n[   15.266227]  hfsplus_ext_read_extent+0x1b2/0x200\n[   15.266233]  hfsplus_file_extend+0x5a7/0x1000\n[   15.266237]  hfsplus_get_block+0x12b/0x8c0\n[   15.266238]  __block_write_begin_int+0x36b/0x12c0\n[   15.266251]  block_write_begin+0x77/0x110\n[   15.266252]  cont_write_begin+0x428/0x720\n[   15.266259]  hfsplus_write_begin+0x51/0x100\n[   15.266262]  cont_write_begin+0x272/0x720\n[   15.266270]  hfsplus_write_begin+0x51/0x100\n[   15.266274]  generic_perform_write+0x321/0x750\n[   15.266285]  generic_file_write_iter+0xc3/0x310\n[   15.266289]  __kernel_write_iter+0x2fd/0x800\n[   15.266296]  dump_user_range+0x2ea/0x910\n[   15.266301]  elf_core_dump+0x2a94/0x2ed0\n[   15.266320]  vfs_coredump+0x1d85/0x45e0\n[   15.266349]  get_signal+0x12e3/0x1990\n[   15.266357]  arch_do_signal_or_restart+0x89/0x580\n[   15.266362]  irqentry_exit_to_user_mode+0xab/0x110\n[   15.266364]  asm_exc_page_fault+0x26/0x30\n[   15.266366] RIP: 0033:0x41bd35\n[   15.266367] Code: bc d1 f3 0f 7f 27 f3 0f 7f 6f 10 f3 0f 7f 77 20 f3 0f 7f 7f 30 49 83 c0 0f 49 29 d0 48 8d 7c 17 31 e9 9f 0b 00 00 66 0f ef c0 \u003cf3\u003e 0f 6f 0e f3 0f 6f 56 10 66 0f 74 c1 66 0f d7 d0 49 83 f8f\n[   15.266369] RSP: 002b:00007ffc9e62d078 EFLAGS: 00010283\n[   15.266371] RAX: 00007ffc9e62d100 RBX: 0000000000000000 RCX: 0000000000000000\n[   15.266372] RDX: 00000000000000e0 RSI: 0000000000000000 RDI: 00007ffc9e62d100\n[   15.266373] RBP: 0000400000000040 R08: 00000000000000e0 R09: 0000000000000000\n[   15.266374] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000\n[   15.266375] R13: 0000000000000000 R14: 0000000000000000 R15: 0000400000000000\n[   15.266376]  \u003c/TASK\u003e\n\nWhen calling hfsplus_bmap_alloc to allocate a free node, this function\nfirst retrieves the bitmap from header node and map node using node-\u003epage\ntogether with the offset and length from hfs_brec_lenoff\n\n```\nlen = hfs_brec_lenoff(node, 2, \u0026off16);\noff = off16;\n\noff += node-\u003epage_offset;\npagep = node-\u003epage + (off \u003e\u003e PAGE_SHIFT);\ndata = kmap_local_page(*pagep);\n```\n\nHowever, if the retrieved offset or length is invalid(i.e. exceeds\nnode_size), the code may end up accessing pages outside the allocated\nrange for this node.\n\nThis patch adds proper validation of both offset and length before use,\npreventing out-of-bounds page access. Move is_bnode_offset_valid and\ncheck_and_correct_requested_length to hfsplus_fs.h, as they may be\nrequired by other functions.",
  "id": "GHSA-fw43-f4rv-3fjg",
  "modified": "2026-07-30T06:32:23Z",
  "published": "2025-12-16T15:30:43Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-40349"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0058d20d76182861dbdd8fd6e2dd8d18d6d3becf"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/068a46df3e6acc68fb9db0a6313ab379a11ecd6f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/17ed51cfce6c62cffb97059ef392ad2e0245806e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/40dfe7a4215a1f20842561ffaf5a6f83a987e75b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/418e48cab99c52c1760636a4dbe464bf6db2018b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4f40a2b3969daf10dca4dea6f6dd0e813f79b227"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/738d5a51864ed8d7a68600b8c0c63fe6fe5c4f20"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f7d9f600c7c3ff5dab36181a388af55f2c95604c"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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