CVE-2021-46927

nitro_enclaves: Use get_user_pages_unlocked() call to handle mmap assert

Severity Score

5.5

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

Track

*SSVC

Descriptions

In the Linux kernel, the following vulnerability has been resolved:

nitro_enclaves: Use get_user_pages_unlocked() call to handle mmap assert

After commit 5b78ed24e8ec ("mm/pagemap: add mmap_assert_locked()
annotations to find_vma*()"), the call to get_user_pages() will trigger
the mmap assert.

static inline void mmap_assert_locked(struct mm_struct *mm)
{
lockdep_assert_held(&mm->mmap_lock);
VM_BUG_ON_MM(!rwsem_is_locked(&mm->mmap_lock), mm);
}

[ 62.521410] kernel BUG at include/linux/mmap_lock.h:156!
...........................................................
[ 62.538938] RIP: 0010:find_vma+0x32/0x80
...........................................................
[ 62.605889] Call Trace:
[ 62.608502] <TASK>
[ 62.610956] ? lock_timer_base+0x61/0x80
[ 62.614106] find_extend_vma+0x19/0x80
[ 62.617195] __get_user_pages+0x9b/0x6a0
[ 62.620356] __gup_longterm_locked+0x42d/0x450
[ 62.623721] ? finish_wait+0x41/0x80
[ 62.626748] ? __kmalloc+0x178/0x2f0
[ 62.629768] ne_set_user_memory_region_ioctl.isra.0+0x225/0x6a0 [nitro_enclaves]
[ 62.635776] ne_enclave_ioctl+0x1cf/0x6d7 [nitro_enclaves]
[ 62.639541] __x64_sys_ioctl+0x82/0xb0
[ 62.642620] do_syscall_64+0x3b/0x90
[ 62.645642] entry_SYSCALL_64_after_hwframe+0x44/0xae

Use get_user_pages_unlocked() when setting the enclave memory regions.
That's a similar pattern as mmap_read_lock() used together with
get_user_pages().

En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: nitro_enclaves: use la llamada get_user_pages_unlocked() para manejar mmap afirmar. Después del commit 5b78ed24e8ec ("mm/pagemap: agregue anotaciones mmap_assert_locked() a find_vma*()"), la llamada a get_user_pages( ) activará la afirmación mmap. estático en línea void mmap_assert_locked(struct mm_struct *mm) { lockdep_assert_held(&mm->mmap_lock); VM_BUG_ON_MM(!rwsem_is_locked(&mm->mmap_lock), mm); } [62.521410] ¡ERROR del kernel en include/linux/mmap_lock.h:156! ................................................. ......... [ 62.538938] RIP: 0010:find_vma+0x32/0x80 ................................. ................................. [ 62.605889] Seguimiento de llamadas: [ 62.608502] [ 62.610956] ? LOCK_TIMER_BASE+0x61/0x80 [62.614106] find_extend_vma+0x19/0x80 [62.617195] __get_user_pages+0x9b/0x6a0 [62.6203356] __guup_longter_locked+0x42d/0x450 [62.620356] terminar_esperar+0x41/0x80 [62.626748]? __kmalloc+0x178/0x2f0 [ 62.629768] ne_set_user_memory_region_ioctl.isra.0+0x225/0x6a0 [nitro_enclaves] [ 62.635776] ne_enclave_ioctl+0x1cf/0x6d7 [nitro_enclaves] [ 62.639541] __x64 _sys_ioctl+0x82/0xb0 [ 62.642620] do_syscall_64+0x3b/0x90 [ 62.645642] Entry_SYSCALL_64_after_hwframe+0x44/0xae Utilice get_user_pages_unlocked() al configurar las regiones de memoria del enclave. Es un patrón similar al mmap_read_lock() usado junto con get_user_pages().

*Credits: N/A

CVSS Scores

NISTv3.1 5.5

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

* Common Vulnerability Scoring System

SSVC

Decision:Track

Exploitation

None

Automatable

Tech. Impact

Partial

* Organization's Worst-case Scenario

Timeline

2024-02-25 CVE Reserved
2024-02-27 CVE Published
2024-02-28 EPSS Updated
2024-08-04 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-667: Improper Locking

CAPEC

References (3)

URL	Tag	Source
https://git.kernel.org/stable/c/5b78ed24e8ec48602c1d6f5a188e58d000c81e2b	Vuln. Introduced

URL	Date	SRC

URL	Date	SRC
https://git.kernel.org/stable/c/90d2beed5e753805c5eab656b8d48257638fe543	2022-01-05
https://git.kernel.org/stable/c/3a0152b219523227c2a62a0a122cf99608287176	2021-12-21

URL	Date	SRC

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 5.15 < 5.15.13 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.15 < 5.15.13"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 5.15 < 5.16 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.15 < 5.16"		en		Affected