ghsa-q4p6-5cf2-247q
Vulnerability from github
Published
2024-10-21 15:32
Modified
2024-11-08 18:30
Severity ?
Details
In the Linux kernel, the following vulnerability has been resolved:
firmware_loader: Block path traversal
Most firmware names are hardcoded strings, or are constructed from fairly constrained format strings where the dynamic parts are just some hex numbers or such.
However, there are a couple codepaths in the kernel where firmware file names contain string components that are passed through from a device or semi-privileged userspace; the ones I could find (not counting interfaces that require root privileges) are:
- lpfc_sli4_request_firmware_update() seems to construct the firmware filename from "ModelName", a string that was previously parsed out of some descriptor ("Vital Product Data") in lpfc_fill_vpd()
- nfp_net_fw_find() seems to construct a firmware filename from a model name coming from nfp_hwinfo_lookup(pf->hwinfo, "nffw.partno"), which I think parses some descriptor that was read from the device. (But this case likely isn't exploitable because the format string looks like "netronome/nic_%s", and there shouldn't be any folders starting with "netronome/nic_". The previous case was different because there, the "%s" is at the start of the format string.)
- module_flash_fw_schedule() is reachable from the ETHTOOL_MSG_MODULE_FW_FLASH_ACT netlink command, which is marked as GENL_UNS_ADMIN_PERM (meaning CAP_NET_ADMIN inside a user namespace is enough to pass the privilege check), and takes a userspace-provided firmware name. (But I think to reach this case, you need to have CAP_NET_ADMIN over a network namespace that a special kind of ethernet device is mapped into, so I think this is not a viable attack path in practice.)
Fix it by rejecting any firmware names containing ".." path components.
For what it's worth, I went looking and haven't found any USB device drivers that use the firmware loader dangerously.
{
"affected": [],
"aliases": [
"CVE-2024-47742"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-10-21T13:15:04Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nfirmware_loader: Block path traversal\n\nMost firmware names are hardcoded strings, or are constructed from fairly\nconstrained format strings where the dynamic parts are just some hex\nnumbers or such.\n\nHowever, there are a couple codepaths in the kernel where firmware file\nnames contain string components that are passed through from a device or\nsemi-privileged userspace; the ones I could find (not counting interfaces\nthat require root privileges) are:\n\n - lpfc_sli4_request_firmware_update() seems to construct the firmware\n filename from \"ModelName\", a string that was previously parsed out of\n some descriptor (\"Vital Product Data\") in lpfc_fill_vpd()\n - nfp_net_fw_find() seems to construct a firmware filename from a model\n name coming from nfp_hwinfo_lookup(pf-\u003ehwinfo, \"nffw.partno\"), which I\n think parses some descriptor that was read from the device.\n (But this case likely isn\u0027t exploitable because the format string looks\n like \"netronome/nic_%s\", and there shouldn\u0027t be any *folders* starting\n with \"netronome/nic_\". The previous case was different because there,\n the \"%s\" is *at the start* of the format string.)\n - module_flash_fw_schedule() is reachable from the\n ETHTOOL_MSG_MODULE_FW_FLASH_ACT netlink command, which is marked as\n GENL_UNS_ADMIN_PERM (meaning CAP_NET_ADMIN inside a user namespace is\n enough to pass the privilege check), and takes a userspace-provided\n firmware name.\n (But I think to reach this case, you need to have CAP_NET_ADMIN over a\n network namespace that a special kind of ethernet device is mapped into,\n so I think this is not a viable attack path in practice.)\n\nFix it by rejecting any firmware names containing \"..\" path components.\n\nFor what it\u0027s worth, I went looking and haven\u0027t found any USB device\ndrivers that use the firmware loader dangerously.",
"id": "GHSA-q4p6-5cf2-247q",
"modified": "2024-11-08T18:30:44Z",
"published": "2024-10-21T15:32:26Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-47742"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/28f1cd94d3f1092728fb775a0fe26c5f1ac2ebeb"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3d2411f4edcb649eaf232160db459bb4770b5251"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6c4e13fdfcab34811c3143a0a03c05fec4e870ec"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7420c1bf7fc784e587b87329cc6dfa3dca537aa4"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9b1ca33ebd05b3acef5b976c04e5e791af93ce1b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a77fc4acfd49fc6076e565445b2bc5fdc3244da4"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c30558e6c5c9ad6c86459d9acce1520ceeab9ea6"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d1768e5535d3ded59f888637016e6f821f4e069f"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f0e5311aa8022107d63c54e2f03684ec097d1394"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
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