ghsa-rwq9-67rv-755x
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
nilfs2: fix underflow in second superblock position calculations
Macro NILFS_SB2_OFFSET_BYTES, which computes the position of the second superblock, underflows when the argument device size is less than 4096 bytes. Therefore, when using this macro, it is necessary to check in advance that the device size is not less than a lower limit, or at least that underflow does not occur.
The current nilfs2 implementation lacks this check, causing out-of-bound block access when mounting devices smaller than 4096 bytes:
I/O error, dev loop0, sector 36028797018963960 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2 NILFS (loop0): unable to read secondary superblock (blocksize = 1024)
In addition, when trying to resize the filesystem to a size below 4096 bytes, this underflow occurs in nilfs_resize_fs(), passing a huge number of segments to nilfs_sufile_resize(), corrupting parameters such as the number of segments in superblocks. This causes excessive loop iterations in nilfs_sufile_resize() during a subsequent resize ioctl, causing semaphore ns_segctor_sem to block for a long time and hang the writer thread:
INFO: task segctord:5067 blocked for more than 143 seconds.
Not tainted 6.2.0-rc8-syzkaller-00015-gf6feea56f66d #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:segctord state:D stack:23456 pid:5067 ppid:2
flags:0x00004000
Call Trace:
This fixes these issues by inserting appropriate minimum device size checks or anti-underflow checks, depending on where the macro is used.
{
"affected": [],
"aliases": [
"CVE-2023-52705"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-05-21T16:15:12Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnilfs2: fix underflow in second superblock position calculations\n\nMacro NILFS_SB2_OFFSET_BYTES, which computes the position of the second\nsuperblock, underflows when the argument device size is less than 4096\nbytes. Therefore, when using this macro, it is necessary to check in\nadvance that the device size is not less than a lower limit, or at least\nthat underflow does not occur.\n\nThe current nilfs2 implementation lacks this check, causing out-of-bound\nblock access when mounting devices smaller than 4096 bytes:\n\n I/O error, dev loop0, sector 36028797018963960 op 0x0:(READ) flags 0x0\n phys_seg 1 prio class 2\n NILFS (loop0): unable to read secondary superblock (blocksize = 1024)\n\nIn addition, when trying to resize the filesystem to a size below 4096\nbytes, this underflow occurs in nilfs_resize_fs(), passing a huge number\nof segments to nilfs_sufile_resize(), corrupting parameters such as the\nnumber of segments in superblocks. This causes excessive loop iterations\nin nilfs_sufile_resize() during a subsequent resize ioctl, causing\nsemaphore ns_segctor_sem to block for a long time and hang the writer\nthread:\n\n INFO: task segctord:5067 blocked for more than 143 seconds.\n Not tainted 6.2.0-rc8-syzkaller-00015-gf6feea56f66d #0\n \"echo 0 \u003e /proc/sys/kernel/hung_task_timeout_secs\" disables this message.\n task:segctord state:D stack:23456 pid:5067 ppid:2\n flags:0x00004000\n Call Trace:\n \u003cTASK\u003e\n context_switch kernel/sched/core.c:5293 [inline]\n __schedule+0x1409/0x43f0 kernel/sched/core.c:6606\n schedule+0xc3/0x190 kernel/sched/core.c:6682\n rwsem_down_write_slowpath+0xfcf/0x14a0 kernel/locking/rwsem.c:1190\n nilfs_transaction_lock+0x25c/0x4f0 fs/nilfs2/segment.c:357\n nilfs_segctor_thread_construct fs/nilfs2/segment.c:2486 [inline]\n nilfs_segctor_thread+0x52f/0x1140 fs/nilfs2/segment.c:2570\n kthread+0x270/0x300 kernel/kthread.c:376\n ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308\n \u003c/TASK\u003e\n ...\n Call Trace:\n \u003cTASK\u003e\n folio_mark_accessed+0x51c/0xf00 mm/swap.c:515\n __nilfs_get_page_block fs/nilfs2/page.c:42 [inline]\n nilfs_grab_buffer+0x3d3/0x540 fs/nilfs2/page.c:61\n nilfs_mdt_submit_block+0xd7/0x8f0 fs/nilfs2/mdt.c:121\n nilfs_mdt_read_block+0xeb/0x430 fs/nilfs2/mdt.c:176\n nilfs_mdt_get_block+0x12d/0xbb0 fs/nilfs2/mdt.c:251\n nilfs_sufile_get_segment_usage_block fs/nilfs2/sufile.c:92 [inline]\n nilfs_sufile_truncate_range fs/nilfs2/sufile.c:679 [inline]\n nilfs_sufile_resize+0x7a3/0x12b0 fs/nilfs2/sufile.c:777\n nilfs_resize_fs+0x20c/0xed0 fs/nilfs2/super.c:422\n nilfs_ioctl_resize fs/nilfs2/ioctl.c:1033 [inline]\n nilfs_ioctl+0x137c/0x2440 fs/nilfs2/ioctl.c:1301\n ...\n\nThis fixes these issues by inserting appropriate minimum device size\nchecks or anti-underflow checks, depending on where the macro is used.",
"id": "GHSA-rwq9-67rv-755x",
"modified": "2024-05-21T18:31:18Z",
"published": "2024-05-21T18:31:18Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-52705"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0ee5ed0126a2211f7174492da2ca2c29f43755c5"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/2f7a1135b202977b82457adde7db6c390056863b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/52844d8382cd9166d708032def8905ffc3ae550f"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/99b9402a36f0799f25feee4465bfa4b8dfa74b4d"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a158782b56b070485d54d25fc9aaf2c8f3752205"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a8ef5109f93cea9933bbac0455d8c18757b3fcb4"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b96591e2c35c8b47db0ec816b5fc6cb8868000ff"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
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