CVE-2024-26983

bootconfig: use memblock_free_late to free xbc memory to buddy

Severity Score

"-"

*CVSS v-

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:

bootconfig: use memblock_free_late to free xbc memory to buddy

On the time to free xbc memory in xbc_exit(), memblock may has handed
over memory to buddy allocator. So it doesn't make sense to free memory
back to memblock. memblock_free() called by xbc_exit() even causes UAF bugs
on architectures with CONFIG_ARCH_KEEP_MEMBLOCK disabled like x86.
Following KASAN logs shows this case.

This patch fixes the xbc memory free problem by calling memblock_free()
in early xbc init error rewind path and calling memblock_free_late() in
xbc exit path to free memory to buddy allocator.

[ 9.410890] ==================================================================
[ 9.418962] BUG: KASAN: use-after-free in memblock_isolate_range+0x12d/0x260
[ 9.426850] Read of size 8 at addr ffff88845dd30000 by task swapper/0/1

[ 9.435901] CPU: 9 PID: 1 Comm: swapper/0 Tainted: G U 6.9.0-rc3-00208-g586b5dfb51b9 #5
[ 9.446403] Hardware name: Intel Corporation RPLP LP5 (CPU:RaptorLake)/RPLP LP5 (ID:13), BIOS IRPPN02.01.01.00.00.19.015.D-00000000 Dec 28 2023
[ 9.460789] Call Trace:
[ 9.463518] <TASK>
[ 9.465859] dump_stack_lvl+0x53/0x70
[ 9.469949] print_report+0xce/0x610
[ 9.473944] ? __virt_addr_valid+0xf5/0x1b0
[ 9.478619] ? memblock_isolate_range+0x12d/0x260
[ 9.483877] kasan_report+0xc6/0x100
[ 9.487870] ? memblock_isolate_range+0x12d/0x260
[ 9.493125] memblock_isolate_range+0x12d/0x260
[ 9.498187] memblock_phys_free+0xb4/0x160
[ 9.502762] ? __pfx_memblock_phys_free+0x10/0x10
[ 9.508021] ? mutex_unlock+0x7e/0xd0
[ 9.512111] ? __pfx_mutex_unlock+0x10/0x10
[ 9.516786] ? kernel_init_freeable+0x2d4/0x430
[ 9.521850] ? __pfx_kernel_init+0x10/0x10
[ 9.526426] xbc_exit+0x17/0x70
[ 9.529935] kernel_init+0x38/0x1e0
[ 9.533829] ? _raw_spin_unlock_irq+0xd/0x30
[ 9.538601] ret_from_fork+0x2c/0x50
[ 9.542596] ? __pfx_kernel_init+0x10/0x10
[ 9.547170] ret_from_fork_asm+0x1a/0x30
[ 9.551552] </TASK>

[ 9.555649] The buggy address belongs to the physical page:
[ 9.561875] page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x45dd30
[ 9.570821] flags: 0x200000000000000(node=0|zone=2)
[ 9.576271] page_type: 0xffffffff()
[ 9.580167] raw: 0200000000000000 ffffea0011774c48 ffffea0012ba1848 0000000000000000
[ 9.588823] raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
[ 9.597476] page dumped because: kasan: bad access detected

[ 9.605362] Memory state around the buggy address:
[ 9.610714] ffff88845dd2ff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[ 9.618786] ffff88845dd2ff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[ 9.626857] >ffff88845dd30000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 9.634930] ^
[ 9.638534] ffff88845dd30080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 9.646605] ffff88845dd30100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 9.654675] ==================================================================

En el kernel de Linux, se resolvió la siguiente vulnerabilidad: bootconfig: use memblock_free_late para liberar memoria xbc para el amigo En el momento de liberar memoria xbc en xbc_exit(), es posible que memblock haya entregado la memoria al asignador de amigos. Por lo tanto, no tiene sentido liberar memoria en Memblock. memblock_free() llamado por xbc_exit() incluso causa errores UAF en arquitecturas con CONFIG_ARCH_KEEP_MEMBLOCK deshabilitado como x86. Los siguientes registros de KASAN muestran este caso. Este parche soluciona el problema de falta de memoria de xbc llamando a memblock_free() en la ruta de rebobinado del error de inicio temprano de xbc y llamando a memblock_free_late() en la ruta de salida de xbc para liberar memoria al asignador de amigos. [9.410890] ================================================= =================== [9.418962] ERROR: KASAN: use-after-free en memblock_isolate_range+0x12d/0x260 [9.426850] Lectura de tamaño 8 en la dirección ffff88845dd30000 por el intercambiador de tareas /0/1 [ 9.435901] CPU: 9 PID: 1 Comm: swapper/0 Contaminado: GU 6.9.0-rc3-00208-g586b5dfb51b9 #5 [ 9.446403] Nombre de hardware: Intel Corporation RPLP LP5 (CPU:RaptorLake)/RPLP LP5 (ID:13), BIOS IRPPN02.01.01.00.00.19.015.D-00000000 28 de diciembre de 2023 [9.460789] Seguimiento de llamadas: [9.463518] [9.465859] dump_stack_lvl+0x53/0x70 [9.469949] puerto+0xce/0x610 [ 9.473944] ? __virt_addr_valid+0xf5/0x1b0 [9.478619]? memblock_isolate_range+0x12d/0x260 [ 9.483877] kasan_report+0xc6/0x100 [ 9.487870] ? memblock_isolate_range+0x12d/0x260 [9.493125] memblock_isolate_range+0x12d/0x260 [9.498187] memblock_phys_free+0xb4/0x160 [9.502762]? __pfx_memblock_phys_free+0x10/0x10 [9.508021]? mutex_unlock+0x7e/0xd0 [9.512111]? __pfx_mutex_unlock+0x10/0x10 [9.516786]? kernel_init_freeable+0x2d4/0x430 [9.521850]? __pfx_kernel_init+0x10/0x10 [ 9.526426] xbc_exit+0x17/0x70 [ 9.529935] kernel_init+0x38/0x1e0 [ 9.533829] ? _raw_spin_unlock_irq+0xd/0x30 [9.538601] ret_from_fork+0x2c/0x50 [9.542596]? __pfx_kernel_init+0x10/0x10 [ 9.547170] ret_from_fork_asm+0x1a/0x30 [ 9.551552] [ 9.555649] La dirección con errores pertenece a la página física: [ 9.561875] página: refcount:0 mapcount:0 mapeo:00000000000 Índice 00000: 0x1 pfn :0x45dd30 [ 9.570821] banderas: 0x200000000000000(nodo=0|zona=2) [ 9.576271] tipo de página: 0xffffffff() [ 9.580167] raw: 0200000000000000 ffffea0011774c48 12ba1848 0000000000000000 [9.588823] raw: 0000000000000001 0000000000000000 00000000ffffffff 000000000000000000000000 [9.597476] página volcada porque: kasan: mal acceso detectado [9.605362] Estado de la memoria alrededor de la dirección con errores: [9.610714] ffff88845dd2ff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 9.618786] ffff88845dd2ff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 9.626857] >ffff88845dd30000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 9.634930] ^ [ 9.638534] ffff88845dd30080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 9.646605] ffff88845dd30100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 9.654675] ======================= ===============================================

*Credits: N/A

CVSS Scores

Attack Vector

Attack Complexity

Privileges Required

User Interaction

Scope

Confidentiality

Integrity

Availability

* Common Vulnerability Scoring System

SSVC

Decision:Track

Exploitation

None

Automatable

Tech. Impact

Partial

* Organization's Worst-case Scenario

Timeline

2024-02-19 CVE Reserved
2024-05-01 CVE Published
2024-05-13 EPSS Updated
2024-09-11 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CAPEC

References (5)

URL	Tag	Source
https://git.kernel.org/stable/c/40caa127f3c7279c75cb0c9684559fa314ee3a66	Vuln. Introduced

URL	Date	SRC

URL	Date	SRC
https://git.kernel.org/stable/c/1e7feb31a18c197d63a5e606025ed63c762f8918	2024-04-27
https://git.kernel.org/stable/c/e46d3be714ad9652480c6db129ab8125e2d20ab7	2024-04-27
https://git.kernel.org/stable/c/5a7dfb8fcd3f29fc93161100179b27f24f3d5f35	2024-04-27
https://git.kernel.org/stable/c/89f9a1e876b5a7ad884918c03a46831af202c8a0	2024-04-14

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 < 6.1.88 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.15 < 6.1.88"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 5.15 < 6.6.29 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.15 < 6.6.29"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 5.15 < 6.8.8 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.15 < 6.8.8"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 5.15 < 6.9 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.15 < 6.9"		en		Affected