In the Linux kernel, the following vulnerability has been resolved:
net/smc: Transitional solution for clcsock race issue
We encountered a crash in smc_setsockopt() and it is caused by
accessing smc->clcsock after clcsock was released.
BUG: kernel NULL pointer dereference, address: 0000000000000020
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 1 PID: 50309 Comm: nginx Kdump: loaded Tainted: G E 5.16.0-rc4+ #53
RIP: 0010:smc_setsockopt+0x59/0x280 [smc]
Call Trace:
<TASK>
__sys_setsockopt+0xfc/0x190
__x64_sys_setsockopt+0x20/0x30
do_syscall_64+0x34/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f16ba83918e
</TASK>
This patch tries to fix it by holding clcsock_release_lock and
checking whether clcsock has already been released before access.
In case that a crash of the same reason happens in smc_getsockopt()
or smc_switch_to_fallback(), this patch also checkes smc->clcsock
in them too. And the caller of smc_switch_to_fallback() will identify
whether fallback succeeds according to the return value.
[
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "unaffected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"net/smc/af_smc.c"
],
"versions": [
{
"version": "fd57770dd198",
"lessThan": "38f0bdd548fd",
"status": "affected",
"versionType": "git"
},
{
"version": "fd57770dd198",
"lessThan": "4284225cd800",
"status": "affected",
"versionType": "git"
},
{
"version": "fd57770dd198",
"lessThan": "c0bf3d8a943b",
"status": "affected",
"versionType": "git"
}
]
},
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "affected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"net/smc/af_smc.c"
],
"versions": [
{
"version": "5.1",
"status": "affected"
},
{
"version": "0",
"lessThan": "5.1",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "5.15.19",
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "5.16.5",
"lessThanOrEqual": "5.16.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "5.17",
"lessThanOrEqual": "*",
"status": "unaffected",
"versionType": "original_commit_for_fix"
}
]
}
]