vulnerability

Amazon Linux AMI: CVE-2023-52813: Security patch for kernel (ALAS-2024-1899)

Severity
10
CVSS
(AV:N/AC:L/Au:N/C:C/I:C/A:C)
Published
01/03/2024
Added
07/04/2024
Modified
02/19/2025

Description

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.

Solution

amazon-linux-upgrade-kernel
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