ghsa-xq4m-hfgr-r2x5
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
nilfs2: fix potential bug in end_buffer_async_write
According to a syzbot report, end_buffer_async_write(), which handles the completion of block device writes, may detect abnormal condition of the buffer async_write flag and cause a BUG_ON failure when using nilfs2.
Nilfs2 itself does not use end_buffer_async_write(). But, the async_write flag is now used as a marker by commit 7f42ec394156 ("nilfs2: fix issue with race condition of competition between segments for dirty blocks") as a means of resolving double list insertion of dirty blocks in nilfs_lookup_dirty_data_buffers() and nilfs_lookup_node_buffers() and the resulting crash.
This modification is safe as long as it is used for file data and b-tree node blocks where the page caches are independent. However, it was irrelevant and redundant to also introduce async_write for segment summary and super root blocks that share buffers with the backing device. This led to the possibility that the BUG_ON check in end_buffer_async_write would fail as described above, if independent writebacks of the backing device occurred in parallel.
The use of async_write for segment summary buffers has already been removed in a previous change.
Fix this issue by removing the manipulation of the async_write flag for the remaining super root block buffer.
{
"affected": [],
"aliases": [
"CVE-2024-26685"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-04-03T15:15:52Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnilfs2: fix potential bug in end_buffer_async_write\n\nAccording to a syzbot report, end_buffer_async_write(), which handles the\ncompletion of block device writes, may detect abnormal condition of the\nbuffer async_write flag and cause a BUG_ON failure when using nilfs2.\n\nNilfs2 itself does not use end_buffer_async_write(). But, the async_write\nflag is now used as a marker by commit 7f42ec394156 (\"nilfs2: fix issue\nwith race condition of competition between segments for dirty blocks\") as\na means of resolving double list insertion of dirty blocks in\nnilfs_lookup_dirty_data_buffers() and nilfs_lookup_node_buffers() and the\nresulting crash.\n\nThis modification is safe as long as it is used for file data and b-tree\nnode blocks where the page caches are independent. However, it was\nirrelevant and redundant to also introduce async_write for segment summary\nand super root blocks that share buffers with the backing device. This\nled to the possibility that the BUG_ON check in end_buffer_async_write\nwould fail as described above, if independent writebacks of the backing\ndevice occurred in parallel.\n\nThe use of async_write for segment summary buffers has already been\nremoved in a previous change.\n\nFix this issue by removing the manipulation of the async_write flag for\nthe remaining super root block buffer.",
"id": "GHSA-xq4m-hfgr-r2x5",
"modified": "2024-06-27T12:30:44Z",
"published": "2024-04-03T15:30:42Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-26685"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/2c3bdba00283a6c7a5b19481a59a730f46063803"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5bc09b397cbf1221f8a8aacb1152650c9195b02b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/626daab3811b772086aef1bf8eed3ffe6f523eff"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6589f0f72f8edd1fa11adce4eedbd3615f2e78ab"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8fa90634ec3e9cc50f42dd605eec60f2d146ced8"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c4a09fdac625e64abe478dcf88bfa20406616928"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d31c8721e816eff5ca6573cc487754f357c093cd"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f3e4963566f58726d3265a727116a42b591f6596"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2024/06/msg00020.html"
}
],
"schema_version": "1.4.0",
"severity": []
}