CVE-2021-47536: net/smc: fix wrong list_del in smc_lgr_cleanup_early
In the Linux kernel, the following vulnerability has been resolved:
net/smc: fix wrong listdel in smclgrcleanupearly
smclgrcleanupearly() meant to delete the link group from the link group list, but it deleted the list head by mistake.
This may cause memory corruption since we didn't remove the real link group from the list and later memseted the link group structure. We got a list corruption panic when testing:
[ 231.277259] listdel corruption. prev->next should be ffff8881398a8000, but was 0000000000000000 [ 231.278222] ------------[ cut here ]------------ [ 231.278726] kernel BUG at lib/listdebug.c:53! [ 231.279326] invalid opcode: 0000 [#1] SMP NOPTI [ 231.279803] CPU: 0 PID: 5 Comm: kworker/0:0 Not tainted 5.10.46+ #435 [ 231.280466] Hardware name: Alibaba Cloud ECS, BIOS 8c24b4c 04/01/2014 [ 231.281248] Workqueue: events smclinkdownwork [ 231.281732] RIP: 0010:listdelentryvalid+0x70/0x90 [ 231.282258] Code: 4c 60 82 e8 7d cc 6a 00 0f 0b 48 89 fe 48 c7 c7 88 4c 60 82 e8 6c cc 6a 00 0f 0b 48 89 fe 48 c7 c7 c0 4c 60 82 e8 5b cc 6a 00 <0f> 0b 48 89 fe 48 c7 c7 00 4d 60 82 e8 4a cc 6a 00 0f 0b cc cc cc [ 231.284146] RSP: 0018:ffffc90000033d58 EFLAGS: 00010292 [ 231.284685] RAX: 0000000000000054 RBX: ffff8881398a8000 RCX: 0000000000000000 [ 231.285415] RDX: 0000000000000001 RSI: ffff88813bc18040 RDI: ffff88813bc18040 [ 231.286141] RBP: ffffffff8305ad40 R08: 0000000000000003 R09: 0000000000000001 [ 231.286873] R10: ffffffff82803da0 R11: ffffc90000033b90 R12: 0000000000000001 [ 231.287606] R13: 0000000000000000 R14: ffff8881398a8000 R15: 0000000000000003 [ 231.288337] FS: 0000000000000000(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000 [ 231.289160] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 231.289754] CR2: 0000000000e72058 CR3: 000000010fa96006 CR4: 00000000003706f0 [ 231.290485] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 231.291211] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 231.291940] Call Trace: [ 231.292211] smclgrterminatesched+0x53/0xa0 [ 231.292677] smcswitchconns+0x75/0x6b0 [ 231.293085] ? updateloadavg+0x1a6/0x590 [ 231.293517] ? ttwudowakeup+0x17/0x150 [ 231.293907] ? updateloadavg+0x1a6/0x590 [ 231.294317] ? newidlebalance+0xca/0x3d0 [ 231.294716] smcrlinkdown+0x50/0x1a0 [ 231.295090] ? wakeupcommonlock+0x77/0x90 [ 231.295534] smclinkdownwork+0x46/0x60 [ 231.295933] processonework+0x18b/0x350
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2021-47536?
CVE-2021-47536 has a high severity rating due to the potential for memory corruption.
How do I fix CVE-2021-47536?
To fix CVE-2021-47536, upgrade your Linux kernel to a version that is not affected, such as 5.10.84 or later.
Which versions of the Linux kernel are affected by CVE-2021-47536?
CVE-2021-47536 affects Linux kernel versions from 5.5 up to 5.10.83 and also the pre-release versions 5.16-rc1 to 5.16-rc3.
What impact does CVE-2021-47536 have on system stability?
CVE-2021-47536 may lead to unexpected memory corruption, potentially impacting the stability and security of the system.
Is there a workaround for CVE-2021-47536 if upgrading is not possible?
There is no known workaround for CVE-2021-47536; upgrading to a patched kernel is the recommended solution.