In the Linux kernel, the following vulnerability has been resolved: net/smc: fix kernel panic caused by race of smc_sock A crash occurs when smc_cdc_tx_handler() tries to access smc_sock but smc_release() has already freed it. [ 4570.695099] BUG: unable to handle page fault for address: 000000002eae9e88 [ 4570.696048] #PF: supervisor write access in kernel mode [ 4570.696728] #PF: error_code(0x0002) - not-present page [ 4570.697401] PGD 0 P4D 0 [ 4570.697716] Oops: 0002 [#1] PREEMPT SMP NOPTI [ 4570.698228] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.16.0-rc4+ #111 [ 4570.699013] Hardware name: Alibaba Cloud Alibaba Cloud ECS, BIOS 8c24b4c 04/0 [ 4570.699933] RIP: 0010:_raw_spin_lock+0x1a/0x30 <...> [ 4570.711446] Call Trace: [ 4570.711746] [ 4570.711992] smc_cdc_tx_handler+0x41/0xc0 [ 4570.712470] smc_wr_tx_tasklet_fn+0x213/0x560 [ 4570.712981] ? smc_cdc_tx_dismisser+0x10/0x10 [ 4570.713489] tasklet_action_common.isra.17+0x66/0x140 [ 4570.714083] __do_softirq+0x123/0x2f4 [ 4570.714521] irq_exit_rcu+0xc4/0xf0 [ 4570.714934] common_interrupt+0xba/0xe0 Though smc_cdc_tx_handler() checked the existence of smc connection, smc_release() may have already dismissed and released the smc socket before smc_cdc_tx_handler() further visits it. smc_cdc_tx_handler() |smc_release() if (!conn) | | |smc_cdc_tx_dismiss_slots() | smc_cdc_tx_dismisser() | |sock_put(&smc->sk) <- last sock_put, | smc_sock freed bh_lock_sock(&smc->sk) (panic) | To make sure we won\'t receive any CDC messages after we free the smc_sock, add a refcount on the smc_connection for inflight CDC message(posted to the QP but haven\'t received related CQE), and don\'t release the smc_connection until all the inflight CDC messages haven been done, for both success or failed ones. Using refcount on CDC messages brings another problem: when the link is going to be destroyed, smcr_link_clear() will reset the QP, which then remove all the pending CQEs related to the QP in the CQ. To make sure all the CQEs will always come back so the refcount on the smc_connection can always reach 0, smc_ib_modify_qp_reset() was replaced by smc_ib_modify_qp_error(). And remove the timeout in smc_wr_tx_wait_no_pending_sends() since we need to wait for all pending WQEs done, or we may encounter use-after- free when handling CQEs. For IB device removal routine, we need to wait for all the QPs on that device been destroyed before we can destroy CQs on the device, or the refcount on smc_connection won\'t reach 0 and smc_sock cannot be released.
Priority: --
CVSS v3: 4.7
Component: linux
Publish Date: Feb 27, 2024
Related ID: --
CVSS v2: MEDIUM
Modified Date: Feb 27, 2024
Find out more about CVE-2021-46925 from the MITRE-CVE dictionary and NIST NVD
Login may be required to access defects or downloads.
| Product Name |
Status |
Defect |
Fixed |
Downloads |
| Linux |
| Wind River Linux LTS 17 |
Requires LTSS |
-- |
-- |
-- |
| Wind River Linux 8 |
Requires LTSS |
-- |
-- |
-- |
| Wind River Linux 9 |
Requires LTSS |
-- |
-- |
-- |
| Wind River Linux 7 |
Requires LTSS |
-- |
-- |
-- |
| Wind River Linux LTS 21 |
Won't Fix |
-- |
-- |
-- |
| Wind River Linux LTS 22 |
Fixed |
LIN1022-6689
|
10.22.33.5 |
-- |
| Wind River Linux LTS 18 |
Requires LTSS |
-- |
-- |
-- |
| Wind River Linux LTS 19 |
Won't Fix |
-- |
-- |
-- |
| Wind River Linux CD release |
N/A |
-- |
-- |
-- |
| Wind River Linux 6 |
Requires LTSS |
-- |
-- |
-- |
| Wind River Linux LTS 23 |
Not Vulnerable |
-- |
-- |
-- |
| VxWorks |
| VxWorks 7 |
Not Vulnerable |
-- |
-- |
-- |
| VxWorks 6.9 |
Not Vulnerable |
-- |
-- |
-- |
| Helix Virtualization Platform Cert Edition |
| Helix Virtualization Platform Cert Edition |
Not Vulnerable |
-- |
-- |
-- |
| Product Name |
Status |
Defect |
Fixed |
Downloads |
Notes
Requires LTSS - customers must have active LTSS (Long Term Security Shield) Support to receive up-to-date information about vulnerabilities that may affect legacy software. Please contact your Wind River account team or see https://docs.windriver.com/bundle/Support_and_Maintenance_Supplemental_Terms_and_Conditions and https://support2.windriver.com/index.php?page=plc for more information.
