CVE-2024-35902 net/rds: fix possible cp null dereference

2024-05-1908:34:55

Linux

github.com

linux kernel

net/rds

null dereference fix

security vulnerability

code analysis

AI Score

6.8

Confidence

High

SSVC

Exploitation

none

Automatable

Technical Impact

partial

JSON

In the Linux kernel, the following vulnerability has been resolved:

net/rds: fix possible cp null dereference

cp might be null, calling cp->cp_conn would produce null dereference

[Simon Horman adds:]

Analysis:

cp is a parameter of __rds_rdma_map and is not reassigned.
The following call-sites pass a NULL cp argument to __rds_rdma_map()
- rds_get_mr()
- rds_get_mr_for_dest
Prior to the code above, the following assumes that cp may be NULL
(which is indicative, but could itself be unnecessary)

trans_private = rs->rs_transport->get_mr(
sg, nents, rs, &mr->r_key, cp ? cp->cp_conn : NULL,
args->vec.addr, args->vec.bytes,
need_odp ? ODP_ZEROBASED : ODP_NOT_NEEDED);
The code modified by this patch is guarded by IS_ERR(trans_private),
where trans_private is assigned as per the previous point in this analysis.

The only implementation of get_mr that I could locate is rds_ib_get_mr()
which can return an ERR_PTR if the conn (4th) argument is NULL.
ret is set to PTR_ERR(trans_private).
rds_ib_get_mr can return ERR_PTR(-ENODEV) if the conn (4th) argument is NULL.
Thus ret may be -ENODEV in which case the code in question will execute.

Conclusion:

cp may be NULL at the point where this patch adds a check;
this patch does seem to address a possible bug

CNA Affected

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
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        "status": "affected",
        "version": "786854141057",
        "lessThan": "d275de8ea7be",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "997efea2bf3a",
        "lessThan": "bcd46782e2ec",
        "versionType": "git"
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      {
        "status": "affected",
        "version": "9dfc15a10dfd",
        "lessThan": "cfb786b03b03",
        "versionType": "git"
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      {
        "status": "affected",
        "version": "b562ebe21ed9",
        "lessThan": "d49fac38479b",
        "versionType": "git"
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      {
        "status": "affected",
        "version": "998fd719e6d6",
        "lessThan": "cbaac2e5488e",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "2b505d052807",
        "lessThan": "92309bed3c5f",
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      {
        "status": "affected",
        "version": "c055fc00c07b",
        "lessThan": "6794090c7420",
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      },
      {
        "status": "affected",
        "version": "c055fc00c07b",
        "lessThan": "62fc3357e079",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "net/rds/rdma.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "6.8"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "6.8",
        "versionType": "custom"
      },
      {
        "status": "unaffected",
        "version": "4.19.312",
        "versionType": "custom",
        "lessThanOrEqual": "4.19.*"
      },
      {
        "status": "unaffected",
        "version": "5.4.274",
        "versionType": "custom",
        "lessThanOrEqual": "5.4.*"
      },
      {
        "status": "unaffected",
        "version": "5.10.215",
        "versionType": "custom",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.154",
        "versionType": "custom",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.85",
        "versionType": "custom",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.26",
        "versionType": "custom",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.8.5",
        "versionType": "custom",
        "lessThanOrEqual": "6.8.*"
      },
      {
        "status": "unaffected",
        "version": "6.9",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "net/rds/rdma.c"
    ],
    "defaultStatus": "affected"
  }
]