CVE-2024-39510: cachefiles: fix slab-use-after-free in cachefiles_ondemand_daemon_read()
First published: Fri Jul 12 2024(Updated: )
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.
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux Linux kernel | >=6.8<6.9.6 | |
| Linux Linux kernel | =6.10-rc1 | |
| Linux Linux kernel | =6.10-rc2 | |
| Linux Linux kernel | =6.10-rc3 | |
| debian/linux | 5.10.223-1 5.10.226-1 6.1.115-1 6.1.119-1 6.11.10-1 6.12.5-1 |
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Reference Links
- https://git.kernel.org/stable/c/3958679c49152391209b32be3357193300a51abd
- https://git.kernel.org/stable/c/93064676a2820420a2d37d7c8289f277fe20793d
- https://git.kernel.org/stable/c/cb55625f8eb9d2de8be4da0c4580d48cbb32058e
- https://git.kernel.org/stable/c/da4a827416066191aafeeccee50a8836a826ba10
- https://git.kernel.org/linus/da4a827416066191aafeeccee50a8836a826ba10
- https://security-tracker.debian.org/tracker/CVE-2024-39510
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-39510
- https://nvd.nist.gov/vuln/detail/CVE-2024-39510
- https://launchpad.net/bugs/cve/CVE-2024-39510
- https://ubuntu.com/security/CVE-2024-39510
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