ghsa-868g-hgv5-rh5v
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
net: dcb: choose correct policy to parse DCB_ATTR_BCN
The dcbnl_bcn_setcfg uses erroneous policy to parse tb[DCB_ATTR_BCN], which is introduced in commit 859ee3c43812 ("DCB: Add support for DCB BCN"). Please see the comment in below code
static int dcbnl_bcn_setcfg(...) { ... ret = nla_parse_nested_deprecated(..., dcbnl_pfc_up_nest, .. ) // !!! dcbnl_pfc_up_nest for attributes // DCB_PFC_UP_ATTR_0 to DCB_PFC_UP_ATTR_ALL in enum dcbnl_pfc_up_attrs ... for (i = DCB_BCN_ATTR_RP_0; i <= DCB_BCN_ATTR_RP_7; i++) { // !!! DCB_BCN_ATTR_RP_0 to DCB_BCN_ATTR_RP_7 in enum dcbnl_bcn_attrs ... value_byte = nla_get_u8(data[i]); ... } ... for (i = DCB_BCN_ATTR_BCNA_0; i <= DCB_BCN_ATTR_RI; i++) { // !!! DCB_BCN_ATTR_BCNA_0 to DCB_BCN_ATTR_RI in enum dcbnl_bcn_attrs ... value_int = nla_get_u32(data[i]); ... } ... }
That is, the nla_parse_nested_deprecated uses dcbnl_pfc_up_nest attributes to parse nlattr defined in dcbnl_pfc_up_attrs. But the following access code fetch each nlattr as dcbnl_bcn_attrs attributes. By looking up the associated nla_policy for dcbnl_bcn_attrs. We can find the beginning part of these two policies are "same".
static const struct nla_policy dcbnl_pfc_up_nest[...] = { [DCB_PFC_UP_ATTR_0] = {.type = NLA_U8}, [DCB_PFC_UP_ATTR_1] = {.type = NLA_U8}, [DCB_PFC_UP_ATTR_2] = {.type = NLA_U8}, [DCB_PFC_UP_ATTR_3] = {.type = NLA_U8}, [DCB_PFC_UP_ATTR_4] = {.type = NLA_U8}, [DCB_PFC_UP_ATTR_5] = {.type = NLA_U8}, [DCB_PFC_UP_ATTR_6] = {.type = NLA_U8}, [DCB_PFC_UP_ATTR_7] = {.type = NLA_U8}, [DCB_PFC_UP_ATTR_ALL] = {.type = NLA_FLAG}, };
static const struct nla_policy dcbnl_bcn_nest[...] = { [DCB_BCN_ATTR_RP_0] = {.type = NLA_U8}, [DCB_BCN_ATTR_RP_1] = {.type = NLA_U8}, [DCB_BCN_ATTR_RP_2] = {.type = NLA_U8}, [DCB_BCN_ATTR_RP_3] = {.type = NLA_U8}, [DCB_BCN_ATTR_RP_4] = {.type = NLA_U8}, [DCB_BCN_ATTR_RP_5] = {.type = NLA_U8}, [DCB_BCN_ATTR_RP_6] = {.type = NLA_U8}, [DCB_BCN_ATTR_RP_7] = {.type = NLA_U8}, [DCB_BCN_ATTR_RP_ALL] = {.type = NLA_FLAG}, // from here is somewhat different [DCB_BCN_ATTR_BCNA_0] = {.type = NLA_U32}, ... [DCB_BCN_ATTR_ALL] = {.type = NLA_FLAG}, };
Therefore, the current code is buggy and this nla_parse_nested_deprecated could overflow the dcbnl_pfc_up_nest and use the adjacent nla_policy to parse attributes from DCB_BCN_ATTR_BCNA_0.
Hence use the correct policy dcbnl_bcn_nest to parse the nested tb[DCB_ATTR_BCN] TLV.
{
"affected": [],
"aliases": [
"CVE-2023-53369"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-09-18T14:15:39Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: dcb: choose correct policy to parse DCB_ATTR_BCN\n\nThe dcbnl_bcn_setcfg uses erroneous policy to parse tb[DCB_ATTR_BCN],\nwhich is introduced in commit 859ee3c43812 (\"DCB: Add support for DCB\nBCN\"). Please see the comment in below code\n\nstatic int dcbnl_bcn_setcfg(...)\n{\n ...\n ret = nla_parse_nested_deprecated(..., dcbnl_pfc_up_nest, .. )\n // !!! dcbnl_pfc_up_nest for attributes\n // DCB_PFC_UP_ATTR_0 to DCB_PFC_UP_ATTR_ALL in enum dcbnl_pfc_up_attrs\n ...\n for (i = DCB_BCN_ATTR_RP_0; i \u003c= DCB_BCN_ATTR_RP_7; i++) {\n // !!! DCB_BCN_ATTR_RP_0 to DCB_BCN_ATTR_RP_7 in enum dcbnl_bcn_attrs\n ...\n value_byte = nla_get_u8(data[i]);\n ...\n }\n ...\n for (i = DCB_BCN_ATTR_BCNA_0; i \u003c= DCB_BCN_ATTR_RI; i++) {\n // !!! DCB_BCN_ATTR_BCNA_0 to DCB_BCN_ATTR_RI in enum dcbnl_bcn_attrs\n ...\n value_int = nla_get_u32(data[i]);\n ...\n }\n ...\n}\n\nThat is, the nla_parse_nested_deprecated uses dcbnl_pfc_up_nest\nattributes to parse nlattr defined in dcbnl_pfc_up_attrs. But the\nfollowing access code fetch each nlattr as dcbnl_bcn_attrs attributes.\nBy looking up the associated nla_policy for dcbnl_bcn_attrs. We can find\nthe beginning part of these two policies are \"same\".\n\nstatic const struct nla_policy dcbnl_pfc_up_nest[...] = {\n [DCB_PFC_UP_ATTR_0] = {.type = NLA_U8},\n [DCB_PFC_UP_ATTR_1] = {.type = NLA_U8},\n [DCB_PFC_UP_ATTR_2] = {.type = NLA_U8},\n [DCB_PFC_UP_ATTR_3] = {.type = NLA_U8},\n [DCB_PFC_UP_ATTR_4] = {.type = NLA_U8},\n [DCB_PFC_UP_ATTR_5] = {.type = NLA_U8},\n [DCB_PFC_UP_ATTR_6] = {.type = NLA_U8},\n [DCB_PFC_UP_ATTR_7] = {.type = NLA_U8},\n [DCB_PFC_UP_ATTR_ALL] = {.type = NLA_FLAG},\n};\n\nstatic const struct nla_policy dcbnl_bcn_nest[...] = {\n [DCB_BCN_ATTR_RP_0] = {.type = NLA_U8},\n [DCB_BCN_ATTR_RP_1] = {.type = NLA_U8},\n [DCB_BCN_ATTR_RP_2] = {.type = NLA_U8},\n [DCB_BCN_ATTR_RP_3] = {.type = NLA_U8},\n [DCB_BCN_ATTR_RP_4] = {.type = NLA_U8},\n [DCB_BCN_ATTR_RP_5] = {.type = NLA_U8},\n [DCB_BCN_ATTR_RP_6] = {.type = NLA_U8},\n [DCB_BCN_ATTR_RP_7] = {.type = NLA_U8},\n [DCB_BCN_ATTR_RP_ALL] = {.type = NLA_FLAG},\n // from here is somewhat different\n [DCB_BCN_ATTR_BCNA_0] = {.type = NLA_U32},\n ...\n [DCB_BCN_ATTR_ALL] = {.type = NLA_FLAG},\n};\n\nTherefore, the current code is buggy and this\nnla_parse_nested_deprecated could overflow the dcbnl_pfc_up_nest and use\nthe adjacent nla_policy to parse attributes from DCB_BCN_ATTR_BCNA_0.\n\nHence use the correct policy dcbnl_bcn_nest to parse the nested\ntb[DCB_ATTR_BCN] TLV.",
"id": "GHSA-868g-hgv5-rh5v",
"modified": "2025-09-18T15:30:33Z",
"published": "2025-09-18T15:30:33Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-53369"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/199fde04bd875d28b3a5ca525eaaa004eec6e947"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/31d49ba033095f6e8158c60f69714a500922e0c3"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5b3dbedb8d4a0f9f7ce904d76b885438af2a21f9"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8e309f43d0ca4051d20736c06a6f84bbddd881da"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a0da2684db18dead3bcee12fb185e596e3d63c2b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ecff20e193207b44fdbfe64d7de89890f0a7fe6c"
}
],
"schema_version": "1.4.0",
"severity": []
}
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