GHSA-X9RP-8J88-VH76
Vulnerability from github – Published: 2024-02-27 12:31 – Updated: 2024-04-10 18:30In the Linux kernel, the following vulnerability has been resolved:
binder: fix async_free_space accounting for empty parcels
In 4.13, commit 74310e06be4d ("android: binder: Move buffer out of area shared with user space") fixed a kernel structure visibility issue. As part of that patch, sizeof(void *) was used as the buffer size for 0-length data payloads so the driver could detect abusive clients sending 0-length asynchronous transactions to a server by enforcing limits on async_free_size.
Unfortunately, on the "free" side, the accounting of async_free_space did not add the sizeof(void *) back. The result was that up to 8-bytes of async_free_space were leaked on every async transaction of 8-bytes or less. These small transactions are uncommon, so this accounting issue has gone undetected for several years.
The fix is to use "buffer_size" (the allocated buffer size) instead of "size" (the logical buffer size) when updating the async_free_space during the free operation. These are the same except for this corner case of asynchronous transactions with payloads < 8 bytes.
{
"affected": [],
"aliases": [
"CVE-2021-46935"
],
"database_specific": {
"cwe_ids": [
"CWE-668"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-02-27T10:15:07Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbinder: fix async_free_space accounting for empty parcels\n\nIn 4.13, commit 74310e06be4d (\"android: binder: Move buffer out of area shared with user space\")\nfixed a kernel structure visibility issue. As part of that patch,\nsizeof(void *) was used as the buffer size for 0-length data payloads so\nthe driver could detect abusive clients sending 0-length asynchronous\ntransactions to a server by enforcing limits on async_free_size.\n\nUnfortunately, on the \"free\" side, the accounting of async_free_space\ndid not add the sizeof(void *) back. The result was that up to 8-bytes of\nasync_free_space were leaked on every async transaction of 8-bytes or\nless. These small transactions are uncommon, so this accounting issue\nhas gone undetected for several years.\n\nThe fix is to use \"buffer_size\" (the allocated buffer size) instead of\n\"size\" (the logical buffer size) when updating the async_free_space\nduring the free operation. These are the same except for this\ncorner case of asynchronous transactions with payloads \u003c 8 bytes.",
"id": "GHSA-x9rp-8j88-vh76",
"modified": "2024-04-10T18:30:47Z",
"published": "2024-02-27T12:31:10Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-46935"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/103b16a8c51f96d5fe063022869ea906c256e5da"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/17691bada6b2f1d5f1c0f6d28cd9d0727023b0ff"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/1cb8444f3114f0bb2f6e3bcadcf09aa4a28425d4"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/2d2df539d05205fd83c404d5f2dff48d36f9b495"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7c7064402609aeb6fb11be1b4ec10673ff17b593"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/cfd0d84ba28c18b531648c9d4a35ecca89ad9901"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
}
]
}
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