Attacker Value
Unknown
(0 users assessed)
Exploitability
Unknown
(0 users assessed)
User Interaction
None
Privileges Required
Low
Attack Vector
Local
0

CVE-2024-39510

Disclosure Date: July 12, 2024 •
CVE-2024-39510 CVSS v3 Base Score: 7.8
Add MITRE ATT&CK tactics and techniques that apply to this CVE.

Description

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

cachefiles: fix slab-use-after-free in cachefiles_ondemand_daemon_read()

We got the following issue in a fuzz test of randomly issuing the restore
command:

==================================================================
BUG: KASAN: slab-use-after-free in cachefiles_ondemand_daemon_read+0xb41/0xb60
Read of size 8 at addr ffff888122e84088 by task ondemand-04-dae/963

CPU: 13 PID: 963 Comm: ondemand-04-dae Not tainted 6.8.0-dirty #564
Call Trace:
kasan_report+0x93/0xc0
cachefiles_ondemand_daemon_read+0xb41/0xb60
vfs_read+0x169/0xb50
ksys_read+0xf5/0x1e0

Allocated by task 116:
kmem_cache_alloc+0x140/0x3a0
cachefiles_lookup_cookie+0x140/0xcd0
fscache_cookie_state_machine+0x43c/0x1230
[…]

Freed by task 792:
kmem_cache_free+0xfe/0x390
cachefiles_put_object+0x241/0x480
fscache_cookie_state_machine+0x5c8/0x1230

[…]

Following is the process that triggers the issue:

 mount  |   daemon_thread1    |    daemon_thread2

cachefiles_withdraw_cookie
cachefiles_ondemand_clean_object(object)
cachefiles_ondemand_send_req
REQ_A = kzalloc(sizeof(*req) + data_len)
wait_for_completion(&REQ_A->done)

        cachefiles_daemon_read
         cachefiles_ondemand_daemon_read
          REQ_A = cachefiles_ondemand_select_req
          msg->object_id = req->object->ondemand->ondemand_id
                              ------ restore ------
                              cachefiles_ondemand_restore
                              xas_for_each(&xas, req, ULONG_MAX)
                               xas_set_mark(&xas, CACHEFILES_REQ_NEW)

                              cachefiles_daemon_read
                               cachefiles_ondemand_daemon_read
                                REQ_A = cachefiles_ondemand_select_req
          copy_to_user(_buffer, msg, n)
           xa_erase(&cache->reqs, id)
           complete(&REQ_A->done)
          ------ close(fd) ------
          cachefiles_ondemand_fd_release
           cachefiles_put_object

cachefiles_put_object
kmem_cache_free(cachefiles_object_jar, object)

                                REQ_A->object->ondemand->ondemand_id
                                 // object UAF !!!

When we see the request within xa_lock, req->object must not have been
freed yet, so grab the reference count of object before xa_unlock to
avoid the above issue.

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CVSS V3 Severity and Metrics
Base Score:
7.8 High
Impact Score:
5.9
Exploitability Score:
1.8
Vector:
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack Vector (AV):
Local
Attack Complexity (AC):
Low
Privileges Required (PR):
Low
User Interaction (UI):
None
Scope (S):
Unchanged
Confidentiality (C):
High
Integrity (I):
High
Availability (A):
High

General Information

Offensive Application
Unknown
Utility Class
Unknown
Ports
Unknown
OS
Unknown
Vulnerable Versions
Linux cb55625f8eb9
Linux 3958679c4915
Linux 93064676a282
Linux not down converted
Prerequisites
Unknown
Discovered By
Unknown
PoC Author
Unknown
Metasploit Module
Unknown
Reporter
Unknown

Vendors

  • linux

Products

  • linux kernel,
  • linux kernel 6.10
Technical Analysis