ghsa-ccf9-6597-4cqp
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
ext4: fix BUG in ext4_mb_new_inode_pa() due to overflow
When we calculate the end position of ext4_free_extent, this position may be exactly where ext4_lblk_t (i.e. uint) overflows. For example, if ac_g_ex.fe_logical is 4294965248 and ac_orig_goal_len is 2048, then the computed end is 0x100000000, which is 0. If ac->ac_o_ex.fe_logical is not the first case of adjusting the best extent, that is, new_bex_end > 0, the following BUG_ON will be triggered:
========================================================= kernel BUG at fs/ext4/mballoc.c:5116! invalid opcode: 0000 [#1] PREEMPT SMP PTI CPU: 3 PID: 673 Comm: xfs_io Tainted: G E 6.5.0-rc1+ #279 RIP: 0010:ext4_mb_new_inode_pa+0xc5/0x430 Call Trace: ext4_mb_use_best_found+0x203/0x2f0 ext4_mb_try_best_found+0x163/0x240 ext4_mb_regular_allocator+0x158/0x1550 ext4_mb_new_blocks+0x86a/0xe10 ext4_ext_map_blocks+0xb0c/0x13a0 ext4_map_blocks+0x2cd/0x8f0 ext4_iomap_begin+0x27b/0x400 iomap_iter+0x222/0x3d0 __iomap_dio_rw+0x243/0xcb0 iomap_dio_rw+0x16/0x80 =========================================================
A simple reproducer demonstrating the problem:
mkfs.ext4 -F /dev/sda -b 4096 100M
mount /dev/sda /tmp/test
fallocate -l1M /tmp/test/tmp
fallocate -l10M /tmp/test/file
fallocate -i -o 1M -l16777203M /tmp/test/file
fsstress -d /tmp/test -l 0 -n 100000 -p 8 &
sleep 10 && killall -9 fsstress
rm -f /tmp/test/tmp
xfs_io -c "open -ad /tmp/test/file" -c "pwrite -S 0xff 0 8192"
We simply refactor the logic for adjusting the best extent by adding a temporary ext4_free_extent ex and use extent_logical_end() to avoid overflow, which also simplifies the code.
{
"affected": [],
"aliases": [
"CVE-2023-54069"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-12-24T13:16:08Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix BUG in ext4_mb_new_inode_pa() due to overflow\n\nWhen we calculate the end position of ext4_free_extent, this position may\nbe exactly where ext4_lblk_t (i.e. uint) overflows. For example, if\nac_g_ex.fe_logical is 4294965248 and ac_orig_goal_len is 2048, then the\ncomputed end is 0x100000000, which is 0. If ac-\u003eac_o_ex.fe_logical is not\nthe first case of adjusting the best extent, that is, new_bex_end \u003e 0, the\nfollowing BUG_ON will be triggered:\n\n=========================================================\nkernel BUG at fs/ext4/mballoc.c:5116!\ninvalid opcode: 0000 [#1] PREEMPT SMP PTI\nCPU: 3 PID: 673 Comm: xfs_io Tainted: G E 6.5.0-rc1+ #279\nRIP: 0010:ext4_mb_new_inode_pa+0xc5/0x430\nCall Trace:\n \u003cTASK\u003e\n ext4_mb_use_best_found+0x203/0x2f0\n ext4_mb_try_best_found+0x163/0x240\n ext4_mb_regular_allocator+0x158/0x1550\n ext4_mb_new_blocks+0x86a/0xe10\n ext4_ext_map_blocks+0xb0c/0x13a0\n ext4_map_blocks+0x2cd/0x8f0\n ext4_iomap_begin+0x27b/0x400\n iomap_iter+0x222/0x3d0\n __iomap_dio_rw+0x243/0xcb0\n iomap_dio_rw+0x16/0x80\n=========================================================\n\nA simple reproducer demonstrating the problem:\n\n\tmkfs.ext4 -F /dev/sda -b 4096 100M\n\tmount /dev/sda /tmp/test\n\tfallocate -l1M /tmp/test/tmp\n\tfallocate -l10M /tmp/test/file\n\tfallocate -i -o 1M -l16777203M /tmp/test/file\n\tfsstress -d /tmp/test -l 0 -n 100000 -p 8 \u0026\n\tsleep 10 \u0026\u0026 killall -9 fsstress\n\trm -f /tmp/test/tmp\n\txfs_io -c \"open -ad /tmp/test/file\" -c \"pwrite -S 0xff 0 8192\"\n\nWe simply refactor the logic for adjusting the best extent by adding\na temporary ext4_free_extent ex and use extent_logical_end() to avoid\noverflow, which also simplifies the code.",
"id": "GHSA-ccf9-6597-4cqp",
"modified": "2025-12-24T15:30:36Z",
"published": "2025-12-24T15:30:36Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-54069"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/58fe961c606c446f5612f6897827b1cac42c2e89"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/83ecffd40c65844a73c2e93d7c841455786605ac"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b7e9ec38b6a0beb5a49cd1e76be0a9a07c218e90"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/bc056e7163ac7db945366de219745cf94f32a3e6"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f2c3a3aa6f11ad9878dbc3a067b0633e07b586c1"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/fcefddf3a151b2c416b20120c06bb1ba9ad676fb"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
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