fkie_cve-2023-53692
Vulnerability from fkie_nvd
Published
2025-10-22 14:15
Modified
2025-10-22 21:12
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: ext4: fix use-after-free read in ext4_find_extent for bigalloc + inline Syzbot found the following issue: loop0: detected capacity change from 0 to 2048 EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 without journal. Quota mode: none. ================================================================== BUG: KASAN: use-after-free in ext4_ext_binsearch_idx fs/ext4/extents.c:768 [inline] BUG: KASAN: use-after-free in ext4_find_extent+0x76e/0xd90 fs/ext4/extents.c:931 Read of size 4 at addr ffff888073644750 by task syz-executor420/5067 CPU: 0 PID: 5067 Comm: syz-executor420 Not tainted 6.2.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1b1/0x290 lib/dump_stack.c:106 print_address_description+0x74/0x340 mm/kasan/report.c:306 print_report+0x107/0x1f0 mm/kasan/report.c:417 kasan_report+0xcd/0x100 mm/kasan/report.c:517 ext4_ext_binsearch_idx fs/ext4/extents.c:768 [inline] ext4_find_extent+0x76e/0xd90 fs/ext4/extents.c:931 ext4_clu_mapped+0x117/0x970 fs/ext4/extents.c:5809 ext4_insert_delayed_block fs/ext4/inode.c:1696 [inline] ext4_da_map_blocks fs/ext4/inode.c:1806 [inline] ext4_da_get_block_prep+0x9e8/0x13c0 fs/ext4/inode.c:1870 ext4_block_write_begin+0x6a8/0x2290 fs/ext4/inode.c:1098 ext4_da_write_begin+0x539/0x760 fs/ext4/inode.c:3082 generic_perform_write+0x2e4/0x5e0 mm/filemap.c:3772 ext4_buffered_write_iter+0x122/0x3a0 fs/ext4/file.c:285 ext4_file_write_iter+0x1d0/0x18f0 call_write_iter include/linux/fs.h:2186 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x7dc/0xc50 fs/read_write.c:584 ksys_write+0x177/0x2a0 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f4b7a9737b9 RSP: 002b:00007ffc5cac3668 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f4b7a9737b9 RDX: 00000000175d9003 RSI: 0000000020000200 RDI: 0000000000000004 RBP: 00007f4b7a933050 R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000079f R11: 0000000000000246 R12: 00007f4b7a9330e0 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 </TASK> Above issue is happens when enable bigalloc and inline data feature. As commit 131294c35ed6 fixed delayed allocation bug in ext4_clu_mapped for bigalloc + inline. But it only resolved issue when has inline data, if inline data has been converted to extent(ext4_da_convert_inline_data_to_extent) before writepages, there is no EXT4_STATE_MAY_INLINE_DATA flag. However i_data is still store inline data in this scene. Then will trigger UAF when find extent. To resolve above issue, there is need to add judge "ext4_has_inline_data(inode)" in ext4_clu_mapped().
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/11c87c8df2cae1d6be83c07e59fef0792de73482
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/14da044725a3ab10affa3566d29c15737c0e67a4
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/40566def189c513be2c694681256d7486cc6e368
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/770b0613637f59f3091dda1ff0c23671a5326b9c
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/835659598c67907b98cd2aa57bb951dfaf675c69
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/96d440bee177669dc0acedca0abd73bae6a9be8b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a34f6dcb78c654ab905642c1b4e7e5fbb4f0babe
Impacted products
Vendor Product Version


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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix use-after-free read in ext4_find_extent for bigalloc + inline\n\nSyzbot found the following issue:\nloop0: detected capacity change from 0 to 2048\nEXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 without journal. Quota mode: none.\n==================================================================\nBUG: KASAN: use-after-free in ext4_ext_binsearch_idx fs/ext4/extents.c:768 [inline]\nBUG: KASAN: use-after-free in ext4_find_extent+0x76e/0xd90 fs/ext4/extents.c:931\nRead of size 4 at addr ffff888073644750 by task syz-executor420/5067\n\nCPU: 0 PID: 5067 Comm: syz-executor420 Not tainted 6.2.0-rc1-syzkaller #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022\nCall Trace:\n \u003cTASK\u003e\n __dump_stack lib/dump_stack.c:88 [inline]\n dump_stack_lvl+0x1b1/0x290 lib/dump_stack.c:106\n print_address_description+0x74/0x340 mm/kasan/report.c:306\n print_report+0x107/0x1f0 mm/kasan/report.c:417\n kasan_report+0xcd/0x100 mm/kasan/report.c:517\n ext4_ext_binsearch_idx fs/ext4/extents.c:768 [inline]\n ext4_find_extent+0x76e/0xd90 fs/ext4/extents.c:931\n ext4_clu_mapped+0x117/0x970 fs/ext4/extents.c:5809\n ext4_insert_delayed_block fs/ext4/inode.c:1696 [inline]\n ext4_da_map_blocks fs/ext4/inode.c:1806 [inline]\n ext4_da_get_block_prep+0x9e8/0x13c0 fs/ext4/inode.c:1870\n ext4_block_write_begin+0x6a8/0x2290 fs/ext4/inode.c:1098\n ext4_da_write_begin+0x539/0x760 fs/ext4/inode.c:3082\n generic_perform_write+0x2e4/0x5e0 mm/filemap.c:3772\n ext4_buffered_write_iter+0x122/0x3a0 fs/ext4/file.c:285\n ext4_file_write_iter+0x1d0/0x18f0\n call_write_iter include/linux/fs.h:2186 [inline]\n new_sync_write fs/read_write.c:491 [inline]\n vfs_write+0x7dc/0xc50 fs/read_write.c:584\n ksys_write+0x177/0x2a0 fs/read_write.c:637\n do_syscall_x64 arch/x86/entry/common.c:50 [inline]\n do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80\n entry_SYSCALL_64_after_hwframe+0x63/0xcd\nRIP: 0033:0x7f4b7a9737b9\nRSP: 002b:00007ffc5cac3668 EFLAGS: 00000246 ORIG_RAX: 0000000000000001\nRAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f4b7a9737b9\nRDX: 00000000175d9003 RSI: 0000000020000200 RDI: 0000000000000004\nRBP: 00007f4b7a933050 R08: 0000000000000000 R09: 0000000000000000\nR10: 000000000000079f R11: 0000000000000246 R12: 00007f4b7a9330e0\nR13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000\n \u003c/TASK\u003e\n\nAbove issue is happens when enable bigalloc and inline data feature. As\ncommit 131294c35ed6 fixed delayed allocation bug in ext4_clu_mapped for\nbigalloc + inline. But it only resolved issue when has inline data, if\ninline data has been converted to extent(ext4_da_convert_inline_data_to_extent)\nbefore writepages, there is no EXT4_STATE_MAY_INLINE_DATA flag. However\ni_data is still store inline data in this scene. Then will trigger UAF\nwhen find extent.\nTo resolve above issue, there is need to add judge \"ext4_has_inline_data(inode)\"\nin ext4_clu_mapped()."
    }
  ],
  "id": "CVE-2023-53692",
  "lastModified": "2025-10-22T21:12:48.953",
  "metrics": {},
  "published": "2025-10-22T14:15:43.670",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/11c87c8df2cae1d6be83c07e59fef0792de73482"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/14da044725a3ab10affa3566d29c15737c0e67a4"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/40566def189c513be2c694681256d7486cc6e368"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/770b0613637f59f3091dda1ff0c23671a5326b9c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/835659598c67907b98cd2aa57bb951dfaf675c69"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/96d440bee177669dc0acedca0abd73bae6a9be8b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a34f6dcb78c654ab905642c1b4e7e5fbb4f0babe"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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