ghsa-8v23-cgh2-vf2c
Vulnerability from github
Published
2024-08-26 12:31
Modified
2024-09-05 21:31
Details

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

ext4: sanity check for NULL pointer after ext4_force_shutdown

Test case: 2 threads write short inline data to a file. In ext4_page_mkwrite the resulting inline data is converted. Handling ext4_grp_locked_error with description "block bitmap and bg descriptor inconsistent: X vs Y free clusters" calls ext4_force_shutdown. The conversion clears EXT4_STATE_MAY_INLINE_DATA but fails for ext4_destroy_inline_data_nolock and ext4_mark_iloc_dirty due to ext4_forced_shutdown. The restoration of inline data fails for the same reason not setting EXT4_STATE_MAY_INLINE_DATA. Without the flag set a regular process path in ext4_da_write_end follows trying to dereference page folio private pointer that has not been set. The fix calls early return with -EIO error shall the pointer to private be NULL.

Sample crash report:

Unable to handle kernel paging request at virtual address dfff800000000004 KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027] Mem abort info: ESR = 0x0000000096000005 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x05: level 1 translation fault Data abort info: ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000 CM = 0, WnR = 0, TnD = 0, TagAccess = 0 GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [dfff800000000004] address between user and kernel address ranges Internal error: Oops: 0000000096000005 [#1] PREEMPT SMP Modules linked in: CPU: 1 PID: 20274 Comm: syz-executor185 Not tainted 6.9.0-rc7-syzkaller-gfda5695d692c #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : __block_commit_write+0x64/0x2b0 fs/buffer.c:2167 lr : __block_commit_write+0x3c/0x2b0 fs/buffer.c:2160 sp : ffff8000a1957600 x29: ffff8000a1957610 x28: dfff800000000000 x27: ffff0000e30e34b0 x26: 0000000000000000 x25: dfff800000000000 x24: dfff800000000000 x23: fffffdffc397c9e0 x22: 0000000000000020 x21: 0000000000000020 x20: 0000000000000040 x19: fffffdffc397c9c0 x18: 1fffe000367bd196 x17: ffff80008eead000 x16: ffff80008ae89e3c x15: 00000000200000c0 x14: 1fffe0001cbe4e04 x13: 0000000000000000 x12: 0000000000000000 x11: 0000000000000001 x10: 0000000000ff0100 x9 : 0000000000000000 x8 : 0000000000000004 x7 : 0000000000000000 x6 : 0000000000000000 x5 : fffffdffc397c9c0 x4 : 0000000000000020 x3 : 0000000000000020 x2 : 0000000000000040 x1 : 0000000000000020 x0 : fffffdffc397c9c0 Call trace: __block_commit_write+0x64/0x2b0 fs/buffer.c:2167 block_write_end+0xb4/0x104 fs/buffer.c:2253 ext4_da_do_write_end fs/ext4/inode.c:2955 [inline] ext4_da_write_end+0x2c4/0xa40 fs/ext4/inode.c:3028 generic_perform_write+0x394/0x588 mm/filemap.c:3985 ext4_buffered_write_iter+0x2c0/0x4ec fs/ext4/file.c:299 ext4_file_write_iter+0x188/0x1780 call_write_iter include/linux/fs.h:2110 [inline] new_sync_write fs/read_write.c:497 [inline] vfs_write+0x968/0xc3c fs/read_write.c:590 ksys_write+0x15c/0x26c fs/read_write.c:643 __do_sys_write fs/read_write.c:655 [inline] __se_sys_write fs/read_write.c:652 [inline] __arm64_sys_write+0x7c/0x90 fs/read_write.c:652 __invoke_syscall arch/arm64/kernel/syscall.c:34 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:48 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:133 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:152 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598 Code: 97f85911 f94002da 91008356 d343fec8 (38796908) ---[ end trace 0000000000000000 ]---


Code disassembly (best guess): 0: 97f85911 bl 0xffffffffffe16444 4: f94002da ldr x26, [x22] 8: 91008356 add x22, x26, #0x20 c: d343fec8 lsr x8, x22, #3 * 10: 38796908 ldrb w8, [x8, x25] <-- trapping instruction

Show details on source website


{
  "affected": [],
  "aliases": [
    "CVE-2024-43898"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-476"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-08-26T11:15:04Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: sanity check for NULL pointer after ext4_force_shutdown\n\nTest case: 2 threads write short inline data to a file.\nIn ext4_page_mkwrite the resulting inline data is converted.\nHandling ext4_grp_locked_error with description \"block bitmap\nand bg descriptor inconsistent: X vs Y free clusters\" calls\next4_force_shutdown. The conversion clears\nEXT4_STATE_MAY_INLINE_DATA but fails for\next4_destroy_inline_data_nolock and ext4_mark_iloc_dirty due\nto ext4_forced_shutdown. The restoration of inline data fails\nfor the same reason not setting EXT4_STATE_MAY_INLINE_DATA.\nWithout the flag set a regular process path in ext4_da_write_end\nfollows trying to dereference page folio private pointer that has\nnot been set. The fix calls early return with -EIO error shall the\npointer to private be NULL.\n\nSample crash report:\n\nUnable to handle kernel paging request at virtual address dfff800000000004\nKASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027]\nMem abort info:\n  ESR = 0x0000000096000005\n  EC = 0x25: DABT (current EL), IL = 32 bits\n  SET = 0, FnV = 0\n  EA = 0, S1PTW = 0\n  FSC = 0x05: level 1 translation fault\nData abort info:\n  ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000\n  CM = 0, WnR = 0, TnD = 0, TagAccess = 0\n  GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0\n[dfff800000000004] address between user and kernel address ranges\nInternal error: Oops: 0000000096000005 [#1] PREEMPT SMP\nModules linked in:\nCPU: 1 PID: 20274 Comm: syz-executor185 Not tainted 6.9.0-rc7-syzkaller-gfda5695d692c #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024\npstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)\npc : __block_commit_write+0x64/0x2b0 fs/buffer.c:2167\nlr : __block_commit_write+0x3c/0x2b0 fs/buffer.c:2160\nsp : ffff8000a1957600\nx29: ffff8000a1957610 x28: dfff800000000000 x27: ffff0000e30e34b0\nx26: 0000000000000000 x25: dfff800000000000 x24: dfff800000000000\nx23: fffffdffc397c9e0 x22: 0000000000000020 x21: 0000000000000020\nx20: 0000000000000040 x19: fffffdffc397c9c0 x18: 1fffe000367bd196\nx17: ffff80008eead000 x16: ffff80008ae89e3c x15: 00000000200000c0\nx14: 1fffe0001cbe4e04 x13: 0000000000000000 x12: 0000000000000000\nx11: 0000000000000001 x10: 0000000000ff0100 x9 : 0000000000000000\nx8 : 0000000000000004 x7 : 0000000000000000 x6 : 0000000000000000\nx5 : fffffdffc397c9c0 x4 : 0000000000000020 x3 : 0000000000000020\nx2 : 0000000000000040 x1 : 0000000000000020 x0 : fffffdffc397c9c0\nCall trace:\n __block_commit_write+0x64/0x2b0 fs/buffer.c:2167\n block_write_end+0xb4/0x104 fs/buffer.c:2253\n ext4_da_do_write_end fs/ext4/inode.c:2955 [inline]\n ext4_da_write_end+0x2c4/0xa40 fs/ext4/inode.c:3028\n generic_perform_write+0x394/0x588 mm/filemap.c:3985\n ext4_buffered_write_iter+0x2c0/0x4ec fs/ext4/file.c:299\n ext4_file_write_iter+0x188/0x1780\n call_write_iter include/linux/fs.h:2110 [inline]\n new_sync_write fs/read_write.c:497 [inline]\n vfs_write+0x968/0xc3c fs/read_write.c:590\n ksys_write+0x15c/0x26c fs/read_write.c:643\n __do_sys_write fs/read_write.c:655 [inline]\n __se_sys_write fs/read_write.c:652 [inline]\n __arm64_sys_write+0x7c/0x90 fs/read_write.c:652\n __invoke_syscall arch/arm64/kernel/syscall.c:34 [inline]\n invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:48\n el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:133\n do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:152\n el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712\n el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730\n el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598\nCode: 97f85911 f94002da 91008356 d343fec8 (38796908)\n---[ end trace 0000000000000000 ]---\n----------------\nCode disassembly (best guess):\n   0:\t97f85911 \tbl\t0xffffffffffe16444\n   4:\tf94002da \tldr\tx26, [x22]\n   8:\t91008356 \tadd\tx22, x26, #0x20\n   c:\td343fec8 \tlsr\tx8, x22, #3\n* 10:\t38796908 \tldrb\tw8, [x8, x25] \u003c-- trapping instruction",
  "id": "GHSA-8v23-cgh2-vf2c",
  "modified": "2024-09-05T21:31:33Z",
  "published": "2024-08-26T12:31:19Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-43898"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3f6bbe6e07e5239294ecc3d2efa70d1f98aed52e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/83f4414b8f84249d538905825b088ff3ae555652"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f619876ccbfd329ae785fe5d3289b9dcd6eb5901"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}


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