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->state)
case NR_STATE_2
nr_state2_machine()
nr_disconnect()
nr_sk(sk)->state = NR_STATE_0
sock_set_flag(sk, SOCK_DEAD)
nr_heartbeat_expiry
switch (nr->state)
case NR_STATE_0
if (sock_flag(sk, SOCK_DESTROY) ||
(sk->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.
[0]: https://syzkaller.appspot.com/bug?extid=d327a1f3b12e1e206c16
OS | Version | Architecture | Package | Version | Filename |
---|---|---|---|---|---|
ubuntu | 20.04 | noarch | linux | < any | UNKNOWN |
ubuntu | 22.04 | noarch | linux | < any | UNKNOWN |
ubuntu | 24.04 | noarch | linux | < any | UNKNOWN |
ubuntu | 20.04 | noarch | linux-aws | < any | UNKNOWN |
ubuntu | 22.04 | noarch | linux-aws | < any | UNKNOWN |
ubuntu | 24.04 | noarch | linux-aws | < any | UNKNOWN |
ubuntu | 20.04 | noarch | linux-aws-5.15 | < any | UNKNOWN |
ubuntu | 22.04 | noarch | linux-aws-6.5 | < any | UNKNOWN |
ubuntu | 20.04 | noarch | linux-azure | < any | UNKNOWN |
ubuntu | 22.04 | noarch | linux-azure | < any | UNKNOWN |
git.kernel.org/linus/0b9130247f3b6a1122478471ff0e014ea96bb735 (6.10-rc5)
git.kernel.org/stable/c/0b9130247f3b6a1122478471ff0e014ea96bb735
git.kernel.org/stable/c/280cf1173726a7059b628c610c71050d5c0b6937
git.kernel.org/stable/c/5391f9db2cab5ef1cb411be1ab7dbec728078fba
git.kernel.org/stable/c/a02fd5d775cf9787ee7698c797e20f2fa13d2e2b
git.kernel.org/stable/c/b6ebe4fed73eedeb73f4540f8edc4871945474c8
git.kernel.org/stable/c/d377f5a28332954b19e373d36823e59830ab1712
git.kernel.org/stable/c/d616876256b38ecf9a1a1c7d674192c5346bc69c
git.kernel.org/stable/c/e07a9c2a850cdebf625e7a1b8171bd23a8554313
launchpad.net/bugs/cve/CVE-2024-41006
nvd.nist.gov/vuln/detail/CVE-2024-41006
security-tracker.debian.org/tracker/CVE-2024-41006
www.cve.org/CVERecord?id=CVE-2024-41006