ghsa-2f9c-chxh-5h7v
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
ext2/dax: Fix ext2_setsize when len is page aligned
PAGE_ALIGN(x) macro gives the next highest value which is multiple of pagesize. But if x is already page aligned then it simply returns x. So, if x passed is 0 in dax_zero_range() function, that means the length gets passed as 0 to ->iomap_begin().
In ext2 it then calls ext2_get_blocks -> max_blocks as 0 and hits bug_on here in ext2_get_blocks(). BUG_ON(maxblocks == 0);
Instead we should be calling dax_truncate_page() here which takes care of it. i.e. it only calls dax_zero_range if the offset is not page/block aligned.
This can be easily triggered with following on fsdax mounted pmem device.
dd if=/dev/zero of=file count=1 bs=512 truncate -s 0 file
[79.525838] EXT2-fs (pmem0): DAX enabled. Warning: EXPERIMENTAL, use at your own risk [79.529376] ext2 filesystem being mounted at /mnt1/test supports timestamps until 2038 (0x7fffffff) [93.793207] ------------[ cut here ]------------ [93.795102] kernel BUG at fs/ext2/inode.c:637! [93.796904] invalid opcode: 0000 [#1] PREEMPT SMP PTI [93.798659] CPU: 0 PID: 1192 Comm: truncate Not tainted 6.3.0-rc2-xfstests-00056-g131086faa369 #139 [93.806459] RIP: 0010:ext2_get_blocks.constprop.0+0x524/0x610 <...> [93.835298] Call Trace: [93.836253] [93.837103] ? lock_acquire+0xf8/0x110 [93.838479] ? d_lookup+0x69/0xd0 [93.839779] ext2_iomap_begin+0xa7/0x1c0 [93.841154] iomap_iter+0xc7/0x150 [93.842425] dax_zero_range+0x6e/0xa0 [93.843813] ext2_setsize+0x176/0x1b0 [93.845164] ext2_setattr+0x151/0x200 [93.846467] notify_change+0x341/0x4e0 [93.847805] ? lock_acquire+0xf8/0x110 [93.849143] ? do_truncate+0x74/0xe0 [93.850452] ? do_truncate+0x84/0xe0 [93.851739] do_truncate+0x84/0xe0 [93.852974] do_sys_ftruncate+0x2b4/0x2f0 [93.854404] do_syscall_64+0x3f/0x90 [93.855789] entry_SYSCALL_64_after_hwframe+0x72/0xdc
{
"affected": [],
"aliases": [
"CVE-2023-53323"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-09-16T17:15:38Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\next2/dax: Fix ext2_setsize when len is page aligned\n\nPAGE_ALIGN(x) macro gives the next highest value which is multiple of\npagesize. But if x is already page aligned then it simply returns x.\nSo, if x passed is 0 in dax_zero_range() function, that means the\nlength gets passed as 0 to -\u003eiomap_begin().\n\nIn ext2 it then calls ext2_get_blocks -\u003e max_blocks as 0 and hits bug_on\nhere in ext2_get_blocks().\n\tBUG_ON(maxblocks == 0);\n\nInstead we should be calling dax_truncate_page() here which takes\ncare of it. i.e. it only calls dax_zero_range if the offset is not\npage/block aligned.\n\nThis can be easily triggered with following on fsdax mounted pmem\ndevice.\n\ndd if=/dev/zero of=file count=1 bs=512\ntruncate -s 0 file\n\n[79.525838] EXT2-fs (pmem0): DAX enabled. Warning: EXPERIMENTAL, use at your own risk\n[79.529376] ext2 filesystem being mounted at /mnt1/test supports timestamps until 2038 (0x7fffffff)\n[93.793207] ------------[ cut here ]------------\n[93.795102] kernel BUG at fs/ext2/inode.c:637!\n[93.796904] invalid opcode: 0000 [#1] PREEMPT SMP PTI\n[93.798659] CPU: 0 PID: 1192 Comm: truncate Not tainted 6.3.0-rc2-xfstests-00056-g131086faa369 #139\n[93.806459] RIP: 0010:ext2_get_blocks.constprop.0+0x524/0x610\n\u003c...\u003e\n[93.835298] Call Trace:\n[93.836253] \u003cTASK\u003e\n[93.837103] ? lock_acquire+0xf8/0x110\n[93.838479] ? d_lookup+0x69/0xd0\n[93.839779] ext2_iomap_begin+0xa7/0x1c0\n[93.841154] iomap_iter+0xc7/0x150\n[93.842425] dax_zero_range+0x6e/0xa0\n[93.843813] ext2_setsize+0x176/0x1b0\n[93.845164] ext2_setattr+0x151/0x200\n[93.846467] notify_change+0x341/0x4e0\n[93.847805] ? lock_acquire+0xf8/0x110\n[93.849143] ? do_truncate+0x74/0xe0\n[93.850452] ? do_truncate+0x84/0xe0\n[93.851739] do_truncate+0x84/0xe0\n[93.852974] do_sys_ftruncate+0x2b4/0x2f0\n[93.854404] do_syscall_64+0x3f/0x90\n[93.855789] entry_SYSCALL_64_after_hwframe+0x72/0xdc",
"id": "GHSA-2f9c-chxh-5h7v",
"modified": "2025-09-16T18:31:27Z",
"published": "2025-09-16T18:31:27Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-53323"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5cee8bfb8cbd99c97aff85d2bf066b6a496e13ab"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9e54fd14bd143c261e52fde74355e85e9526c58c"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/fcced95b6ba2a507a83b8b3e0358a8ac16b13e35"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
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