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LinuxCVE-2021-4442

HistoryAug 29, 2024 - 11:15 a.m.

CVE-2021-4442

2024-08-2911:15:23

Linux

web.nvd.nist.gov

linux kernel

tcp_queue_seq

qingyu li

syzkaller bug

mprotect

mmap

socket

setsockopt

connect

sendmsg

recvfrom

tcp recvmsg seq

cpu

pid

net/ipv4/tcp.c

tcp_recvmsg_locked

CVSS3

5.5

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

AI Score

6.4

Confidence

High

EPSS

0.001

Percentile

17.8%

JSON

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

tcp: add sanity tests to TCP_QUEUE_SEQ

Qingyu Li reported a syzkaller bug where the repro
changes RCV SEQ after restoring data in the receive queue.

mprotect(0x4aa000, 12288, PROT_READ) = 0
mmap(0x1ffff000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x1ffff000
mmap(0x20000000, 16777216, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x20000000
mmap(0x21000000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x21000000
socket(AF_INET6, SOCK_STREAM, IPPROTO_IP) = 3
setsockopt(3, SOL_TCP, TCP_REPAIR, [1], 4) = 0
connect(3, {sa_family=AF_INET6, sin6_port=htons(0), sin6_flowinfo=htonl(0), inet_pton(AF_INET6, “::1”, &sin6_addr), sin6_scope_id=0}, 28) = 0
setsockopt(3, SOL_TCP, TCP_REPAIR_QUEUE, [1], 4) = 0
sendmsg(3, {msg_name=NULL, msg_namelen=0, msg_iov=[{iov_base=“0x0000000000000003\0\0”, iov_len=20}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, 0) = 20
setsockopt(3, SOL_TCP, TCP_REPAIR, [0], 4) = 0
setsockopt(3, SOL_TCP, TCP_QUEUE_SEQ, [128], 4) = 0
recvfrom(3, NULL, 20, 0, NULL, NULL) = -1 ECONNRESET (Connection reset by peer)

syslog shows:
[ 111.205099] TCP recvmsg seq # bug 2: copied 80, seq 0, rcvnxt 80, fl 0
[ 111.207894] WARNING: CPU: 1 PID: 356 at net/ipv4/tcp.c:2343 tcp_recvmsg_locked+0x90e/0x29a0

This should not be allowed. TCP_QUEUE_SEQ should only be used
when queues are empty.

This patch fixes this case, and the tx path as well.

Affected configurations

Nvd

Vulners

Node

linuxlinux_kernelRange3.5–4.19.181

linuxlinux_kernelRange4.20–5.4.106

linuxlinux_kernelRange5.5–5.10.24

linuxlinux_kernelRange5.11–5.11.7

linuxlinux_kernelMatch5.12rc1

linuxlinux_kernelMatch5.12rc2

VendorProductVersionCPE
linuxlinux_kernel*cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linuxlinux_kernel5.12cpe:2.3:o:linux:linux_kernel:5.12:rc1:*:*:*:*:*:*
linuxlinux_kernel5.12cpe:2.3:o:linux:linux_kernel:5.12:rc2:*:*:*:*:*:*

Vendor	Product	Version	CPE
linux	linux_kernel	*	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	5.12	cpe:2.3:o:linux:linux_kernel:5.12:rc1::::::
linux	linux_kernel	5.12	cpe:2.3:o:linux:linux_kernel:5.12:rc2::::::

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "net/ipv4/tcp.c"
    ],
    "versions": [
      {
        "version": "ee9952831cfd",
        "lessThan": "319f460237fc",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "ee9952831cfd",
        "lessThan": "3bf899438c12",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "ee9952831cfd",
        "lessThan": "046f3c1c2ff4",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "ee9952831cfd",
        "lessThan": "3b72d5a70384",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "ee9952831cfd",
        "lessThan": "8811f4a9836e",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "net/ipv4/tcp.c"
    ],
    "versions": [
      {
        "version": "3.5",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "3.5",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.19.181",
        "lessThanOrEqual": "4.19.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.4.106",
        "lessThanOrEqual": "5.4.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.10.24",
        "lessThanOrEqual": "5.10.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.11.7",
        "lessThanOrEqual": "5.11.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.12",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]