Bug 1225527 (CVE-2023-52813)

Summary: VUL-0: CVE-2023-52813: kernel: crypto: pcrypt - fix hungtask for PADATA_RESET
Product: [Novell Products] SUSE Security Incidents Reporter: SMASH SMASH <smash_bz>
Component: IncidentsAssignee: Nicolai Stange <nstange>
Status: NEW --- QA Contact: Security Team bot <security-team>
Severity: Normal    
Priority: P3 - Medium CC: camila.matos, jlee
Version: unspecified   
Target Milestone: ---   
Hardware: Other   
OS: Other   
URL: https://smash.suse.de/issue/407223/
Whiteboard: CVSSv3.1:SUSE:CVE-2023-52813:5.5:(AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
Found By: Security Response Team Services Priority:
Business Priority: Blocker: ---
Marketing QA Status: --- IT Deployment: ---

Description SMASH SMASH 2024-05-28 18:05:22 UTC
In the Linux kernel, the following vulnerability has been resolved:

crypto: pcrypt - Fix hungtask for PADATA_RESET

We found a hungtask bug in test_aead_vec_cfg as follows:

INFO: task cryptomgr_test:391009 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
Call trace:
 __switch_to+0x98/0xe0
 __schedule+0x6c4/0xf40
 schedule+0xd8/0x1b4
 schedule_timeout+0x474/0x560
 wait_for_common+0x368/0x4e0
 wait_for_completion+0x20/0x30
 wait_for_completion+0x20/0x30
 test_aead_vec_cfg+0xab4/0xd50
 test_aead+0x144/0x1f0
 alg_test_aead+0xd8/0x1e0
 alg_test+0x634/0x890
 cryptomgr_test+0x40/0x70
 kthread+0x1e0/0x220
 ret_from_fork+0x10/0x18
 Kernel panic - not syncing: hung_task: blocked tasks

For padata_do_parallel, when the return err is 0 or -EBUSY, it will call
wait_for_completion(&wait->completion) in test_aead_vec_cfg. In normal
case, aead_request_complete() will be called in pcrypt_aead_serial and the
return err is 0 for padata_do_parallel. But, when pinst->flags is
PADATA_RESET, the return err is -EBUSY for padata_do_parallel, and it
won't call aead_request_complete(). Therefore, test_aead_vec_cfg will
hung at wait_for_completion(&wait->completion), which will cause
hungtask.

The problem comes as following:
(padata_do_parallel)                 |
    rcu_read_lock_bh();              |
    err = -EINVAL;                   |   (padata_replace)
                                     |     pinst->flags |= PADATA_RESET;
    err = -EBUSY                     |
    if (pinst->flags & PADATA_RESET) |
        rcu_read_unlock_bh()         |
        return err

In order to resolve the problem, we replace the return err -EBUSY with
-EAGAIN, which means parallel_data is changing, and the caller should call
it again.

v3:
remove retry and just change the return err.
v2:
introduce padata_try_do_parallel() in pcrypt_aead_encrypt and
pcrypt_aead_decrypt to solve the hungtask.

References:
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2023-52813
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2023/CVE-2023-52813.mbox
https://git.kernel.org/stable/c/fb2d3a50a8f29a3c66682bb426144f40e32ab818
https://git.kernel.org/stable/c/039fec48e062504f14845124a1a25eb199b2ddc0
https://git.kernel.org/stable/c/c9c1334697301c10e6918d747ed38abfbc0c96e7
https://git.kernel.org/stable/c/e97bf4ada7dddacd184c3e196bd063b0dc71b41d
https://git.kernel.org/stable/c/546c1796ad1ed0d87dab3c4b5156d75819be2316
https://git.kernel.org/stable/c/c55fc098fd9d2dca475b82d00ffbcaf97879d77e
https://git.kernel.org/stable/c/e134f3aba98e6c801a693f540912c2d493718ddf
https://git.kernel.org/stable/c/372636debe852913529b1716f44addd94fff2d28
https://git.kernel.org/stable/c/8f4f68e788c3a7a696546291258bfa5fdb215523
https://www.cve.org/CVERecord?id=CVE-2023-52813
https://bugzilla.redhat.com/show_bug.cgi?id=2282653