CVE-2024-26851 netfilter: nf_conntrack_h323: Add protection for bmp length out of range

2024-04-1710:17:15

Linux

github.com

linux kernel

netfilter

nf_conntrack_h323

bmp length

out of range

ubsan load

exception

vmlinux

decode_seq

skb->data

shift operation

negative shift

undefined behaviour

out of range error

decoding

cve

6.7 Medium

AI Score

Confidence

Low

0.0004 Low

EPSS

Percentile

13.2%

JSON

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

netfilter: nf_conntrack_h323: Add protection for bmp length out of range

UBSAN load reports an exception of BRK#5515 SHIFT_ISSUE:Bitwise shifts
that are out of bounds for their data type.

vmlinux get_bitmap(b=75) + 712
<net/netfilter/nf_conntrack_h323_asn1.c:0>
vmlinux decode_seq(bs=0xFFFFFFD008037000, f=0xFFFFFFD008037018, level=134443100) + 1956
<net/netfilter/nf_conntrack_h323_asn1.c:592>
vmlinux decode_choice(base=0xFFFFFFD0080370F0, level=23843636) + 1216
<net/netfilter/nf_conntrack_h323_asn1.c:814>
vmlinux decode_seq(f=0xFFFFFFD0080371A8, level=134443500) + 812
<net/netfilter/nf_conntrack_h323_asn1.c:576>
vmlinux decode_choice(base=0xFFFFFFD008037280, level=0) + 1216
<net/netfilter/nf_conntrack_h323_asn1.c:814>
vmlinux DecodeRasMessage() + 304
<net/netfilter/nf_conntrack_h323_asn1.c:833>
vmlinux ras_help() + 684
<net/netfilter/nf_conntrack_h323_main.c:1728>
vmlinux nf_confirm() + 188
<net/netfilter/nf_conntrack_proto.c:137>

Due to abnormal data in skb->data, the extension bitmap length
exceeds 32 when decoding ras message then uses the length to make
a shift operation. It will change into negative after several loop.
UBSAN load could detect a negative shift as an undefined behaviour
and reports exception.
So we add the protection to avoid the length exceeding 32. Or else
it will return out of range error and stop decoding.

CNA Affected

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5e35941d9901",
        "lessThan": "98db42191329",
        "versionType": "git"
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      {
        "status": "affected",
        "version": "5e35941d9901",
        "lessThan": "4bafcc43baf7",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "5e35941d9901",
        "lessThan": "ccd1108b16ab",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "5e35941d9901",
        "lessThan": "b3c0f5538205",
        "versionType": "git"
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      {
        "status": "affected",
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        "lessThan": "39001e3c4200",
        "versionType": "git"
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        "status": "affected",
        "version": "5e35941d9901",
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        "versionType": "git"
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        "status": "affected",
        "version": "5e35941d9901",
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      },
      {
        "status": "affected",
        "version": "5e35941d9901",
        "lessThan": "767146637efc",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "net/netfilter/nf_conntrack_h323_asn1.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "2.6.17"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "2.6.17",
        "versionType": "custom"
      },
      {
        "status": "unaffected",
        "version": "4.19.310",
        "versionType": "custom",
        "lessThanOrEqual": "4.19.*"
      },
      {
        "status": "unaffected",
        "version": "5.4.272",
        "versionType": "custom",
        "lessThanOrEqual": "5.4.*"
      },
      {
        "status": "unaffected",
        "version": "5.10.213",
        "versionType": "custom",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.152",
        "versionType": "custom",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.82",
        "versionType": "custom",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.22",
        "versionType": "custom",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.7.10",
        "versionType": "custom",
        "lessThanOrEqual": "6.7.*"
      },
      {
        "status": "unaffected",
        "version": "6.8",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "net/netfilter/nf_conntrack_h323_asn1.c"
    ],
    "defaultStatus": "affected"
  }
]