CVE-2024-41006 netrom: Fix a memory leak in nr_heartbeat_expiry()

2024-07-1212:44:41

Linux

www.cve.org

linux kernel

vulnerability

netrom

memory leak

nr_heartbeat_expiry

sock_hold

listening socket

infotecs

linux verification center

syzkaller

EPSS

Percentile

5.0%

JSON

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

netrom: Fix a memory leak in nr_heartbeat_expiry()

syzbot reported a memory leak in nr_create() 0.

Commit 409db27e3a2e (“netrom: Fix use-after-free of a listening socket.”)
added sock_hold() to the nr_heartbeat_expiry() function, where
a) a socket has a SOCK_DESTROY flag or
b) a listening socket has a SOCK_DEAD flag.

But in the case “a,” when the SOCK_DESTROY flag is set, the file descriptor
has already been closed and the nr_release() function has been called.
So it makes no sense to hold the reference count because no one will
call another nr_destroy_socket() and put it as in the case “b.”

nr_connect
nr_establish_data_link
nr_start_heartbeat

nr_release
switch (nr->state)
case NR_STATE_3
nr->state = NR_STATE_2
sock_set_flag(sk, SOCK_DESTROY);

                    nr_rx_frame
                      nr_process_rx_frame
                        switch (nr-&gt;state)
                        case NR_STATE_2
                          nr_state2_machine()
                            nr_disconnect()
                              nr_sk(sk)-&gt;state = NR_STATE_0
                              sock_set_flag(sk, SOCK_DEAD)

                    nr_heartbeat_expiry
                      switch (nr-&gt;state)
                      case NR_STATE_0
                        if (sock_flag(sk, SOCK_DESTROY) ||
                           (sk-&gt;sk_state == TCP_LISTEN
                             && sock_flag(sk, SOCK_DEAD)))
                           sock_hold()  // ( !!! )
                           nr_destroy_socket()

To fix the memory leak, let’s call sock_hold() only for a listening socket.

Found by InfoTeCS on behalf of Linux Verification Center
(linuxtesting.org) with Syzkaller.

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "net/netrom/nr_timer.c"
    ],
    "versions": [
      {
        "version": "a31caf5779ac",
        "lessThan": "d616876256b3",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "fe9b9e621ceb",
        "lessThan": "e07a9c2a850c",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "7de16d75b20a",
        "lessThan": "5391f9db2cab",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "d2d3ab1b1de3",
        "lessThan": "280cf1173726",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "51e394c6f81a",
        "lessThan": "a02fd5d775cf",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "409db27e3a2e",
        "lessThan": "b6ebe4fed73e",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "409db27e3a2e",
        "lessThan": "d377f5a28332",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "409db27e3a2e",
        "lessThan": "0b9130247f3b",
        "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/netrom/nr_timer.c"
    ],
    "versions": [
      {
        "version": "6.2",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "6.2",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.19.317",
        "lessThanOrEqual": "4.19.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.4.279",
        "lessThanOrEqual": "5.4.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.10.221",
        "lessThanOrEqual": "5.10.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.15.162",
        "lessThanOrEqual": "5.15.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.1.96",
        "lessThanOrEqual": "6.1.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.6.36",
        "lessThanOrEqual": "6.6.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.9.7",
        "lessThanOrEqual": "6.9.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.10",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]