416baaa9-dc9f-4396-8d5f-8c081fb06d67CVE-2024-26674CVE-2024-26674
In the Linux kernel, the following vulnerability has been resolved:
x86/lib: Revert to _ASM_EXTABLE_UA() for {get,put}_user() fixups
During memory error injection test on kernels >= v6.4, the kernel panics
like below. However, this issue couldn’t be reproduced on kernels <= v6.3.
mce: [Hardware Error]: CPU 296: Machine Check Exception: f Bank 1: bd80000000100134
mce: [Hardware Error]: RIP 10:<ffffffff821b9776> {__get_user_nocheck_4+0x6/0x20}
mce: [Hardware Error]: TSC 411a93533ed ADDR 346a8730040 MISC 86
mce: [Hardware Error]: PROCESSOR 0:a06d0 TIME 1706000767 SOCKET 1 APIC 211 microcode 80001490
mce: [Hardware Error]: Run the above through ‘mcelog --ascii’
mce: [Hardware Error]: Machine check: Data load in unrecoverable area of kernel
Kernel panic - not syncing: Fatal local machine check
The MCA code can recover from an in-kernel #MC if the fixup type is
EX_TYPE_UACCESS, explicitly indicating that the kernel is attempting to
access userspace memory. However, if the fixup type is EX_TYPE_DEFAULT
the only thing that is raised for an in-kernel #MC is a panic.
ex_handler_uaccess() would warn if users gave a non-canonical addresses
(with bit 63 clear) to {get, put}_user(), which was unexpected.
Therefore, commit
b19b74bc99b1 (“x86/mm: Rework address range check in get_user() and put_user()”)
replaced _ASM_EXTABLE_UA() with _ASM_EXTABLE() for {get, put}_user()
fixups. However, the new fixup type EX_TYPE_DEFAULT results in a panic.
Commit
6014bc27561f (“x86-64: make access_ok() independent of LAM”)
added the check gp_fault_address_ok() right before the WARN_ONCE() in
ex_handler_uaccess() to not warn about non-canonical user addresses due
to LAM.
With that in place, revert back to _ASM_EXTABLE_UA() for {get,put}_user()
exception fixups in order to be able to handle in-kernel MCEs correctly
again.
[ bp: Massage commit message. ]
Affected configurations
| Vendor | Product | Version | CPE |
|---|---|---|---|
| linux | linux_kernel | * | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | * | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | * | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
CNA Affected
[
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "unaffected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"arch/x86/lib/getuser.S",
"arch/x86/lib/putuser.S"
],
"versions": [
{
"version": "b19b74bc99b1",
"lessThan": "2aed1b6c33af",
"status": "affected",
"versionType": "git"
},
{
"version": "b19b74bc99b1",
"lessThan": "2da241c5ed78",
"status": "affected",
"versionType": "git"
},
{
"version": "b19b74bc99b1",
"lessThan": "8eed4e00a370",
"status": "affected",
"versionType": "git"
}
]
},
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "affected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"arch/x86/lib/getuser.S",
"arch/x86/lib/putuser.S"
],
"versions": [
{
"version": "6.4",
"status": "affected"
},
{
"version": "0",
"lessThan": "6.4",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.6.17",
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.7.5",
"lessThanOrEqual": "6.7.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.8",
"lessThanOrEqual": "*",
"status": "unaffected",
"versionType": "original_commit_for_fix"
}
]
}
]Related
