CVE-2022-48819 tcp: take care of mixed splice()/sendmsg(MSG_ZEROCOPY) case

2024-07-1611:44:06

Linux

www.cve.org

linux kernel

cve-2022-48819

vulnerability

mixed splice

sendmsg

tcp socket

warning

inet_sock_destruct

sk_forward_alloc

talal

sendpage()

msg_zerocopy

skb

tcp_downgrade_zcopy_pure

EPSS

Percentile

9.3%

JSON

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

tcp: take care of mixed splice()/sendmsg(MSG_ZEROCOPY) case

syzbot found that mixing sendpage() and sendmsg(MSG_ZEROCOPY)
calls over the same TCP socket would again trigger the
infamous warning in inet_sock_destruct()

WARN_ON(sk_forward_alloc_get(sk));

While Talal took into account a mix of regular copied data
and MSG_ZEROCOPY one in the same skb, the sendpage() path
has been forgotten.

We want the charging to happen for sendpage(), because
pages could be coming from a pipe. What is missing is the
downgrading of pure zerocopy status to make sure
sk_forward_alloc will stay synced.

Add tcp_downgrade_zcopy_pure() helper so that we can
use it from the two callers.

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": "9b65b17db723",
        "lessThan": "47f3860c4931",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "9b65b17db723",
        "lessThan": "f8d9d938514f",
        "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": "5.16",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "5.16",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.16.10",
        "lessThanOrEqual": "5.16.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.17",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]