CVE-2021-47428

powerpc/64s: fix program check interrupt emergency stack path

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:

powerpc/64s: fix program check interrupt emergency stack path

Emergency stack path was jumping into a 3: label inside the
__GEN_COMMON_BODY macro for the normal path after it had finished,
rather than jumping over it. By a small miracle this is the correct
place to build up a new interrupt frame with the existing stack
pointer, so things basically worked okay with an added weird looking
700 trap frame on top (which had the wrong ->nip so it didn't decode
bug messages either).

Fix this by avoiding using numeric labels when jumping over non-trivial
macros.

Before:

LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA PowerNV
Modules linked in:
CPU: 0 PID: 88 Comm: sh Not tainted 5.15.0-rc2-00034-ge057cdade6e5 #2637
NIP: 7265677368657265 LR: c00000000006c0c8 CTR: c0000000000097f0
REGS: c0000000fffb3a50 TRAP: 0700 Not tainted
MSR: 9000000000021031 <SF,HV,ME,IR,DR,LE> CR: 00000700 XER: 20040000
CFAR: c0000000000098b0 IRQMASK: 0
GPR00: c00000000006c964 c0000000fffb3cf0 c000000001513800 0000000000000000
GPR04: 0000000048ab0778 0000000042000000 0000000000000000 0000000000001299
GPR08: 000001e447c718ec 0000000022424282 0000000000002710 c00000000006bee8
GPR12: 9000000000009033 c0000000016b0000 00000000000000b0 0000000000000001
GPR16: 0000000000000000 0000000000000002 0000000000000000 0000000000000ff8
GPR20: 0000000000001fff 0000000000000007 0000000000000080 00007fff89d90158
GPR24: 0000000002000000 0000000002000000 0000000000000255 0000000000000300
GPR28: c000000001270000 0000000042000000 0000000048ab0778 c000000080647e80
NIP [7265677368657265] 0x7265677368657265
LR [c00000000006c0c8] ___do_page_fault+0x3f8/0xb10
Call Trace:
[c0000000fffb3cf0] [c00000000000bdac] soft_nmi_common+0x13c/0x1d0 (unreliable)
--- interrupt: 700 at decrementer_common_virt+0xb8/0x230
NIP: c0000000000098b8 LR: c00000000006c0c8 CTR: c0000000000097f0
REGS: c0000000fffb3d60 TRAP: 0700 Not tainted
MSR: 9000000000021031 <SF,HV,ME,IR,DR,LE> CR: 22424282 XER: 20040000
CFAR: c0000000000098b0 IRQMASK: 0
GPR00: c00000000006c964 0000000000002400 c000000001513800 0000000000000000
GPR04: 0000000048ab0778 0000000042000000 0000000000000000 0000000000001299
GPR08: 000001e447c718ec 0000000022424282 0000000000002710 c00000000006bee8
GPR12: 9000000000009033 c0000000016b0000 00000000000000b0 0000000000000001
GPR16: 0000000000000000 0000000000000002 0000000000000000 0000000000000ff8
GPR20: 0000000000001fff 0000000000000007 0000000000000080 00007fff89d90158
GPR24: 0000000002000000 0000000002000000 0000000000000255 0000000000000300
GPR28: c000000001270000 0000000042000000 0000000048ab0778 c000000080647e80
NIP [c0000000000098b8] decrementer_common_virt+0xb8/0x230
LR [c00000000006c0c8] ___do_page_fault+0x3f8/0xb10
--- interrupt: 700
Instruction dump:
XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
---[ end trace 6d28218e0cc3c949 ]---

After:

------------[ cut here ]------------
kernel BUG at arch/powerpc/kernel/exceptions-64s.S:491!
Oops: Exception in kernel mode, sig: 5 [#1]
LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA PowerNV
Modules linked in:
CPU: 0 PID: 88 Comm: login Not tainted 5.15.0-rc2-00034-ge057cdade6e5-dirty #2638
NIP: c0000000000098b8 LR: c00000000006bf04 CTR: c0000000000097f0
REGS: c0000000fffb3d60 TRAP: 0700 Not tainted
MSR: 9000000000021031 <SF,HV,ME,IR,DR,LE> CR: 24482227 XER: 00040000
CFAR: c0000000000098b0 IRQMASK: 0
GPR00: c00000000006bf04 0000000000002400 c000000001513800 c000000001271868
GPR04: 00000000100f0d29 0000000042000000 0000000000000007 0000000000000009
GPR08: 00000000100f0d29 0000000024482227 0000000000002710 c000000000181b3c
GPR12: 9000000000009033 c0000000016b0000 00000000100f0d29 c000000005b22f00
GPR16: 00000000ffff0000 0000000000000001 0000000000000009 00000000100eed90
GPR20: 00000000100eed90 00000
---truncated---

En el kernel de Linux, se resolvió la siguiente vulnerabilidad: powerpc/64s: programa de reparación, verificación, interrupción, ruta de pila de emergencia. La ruta de pila de emergencia saltaba a una etiqueta 3: dentro de la macro __GEN_COMMON_BODY para la ruta normal después de haber terminado, en lugar de saltar por encima. él. Por un pequeño milagro, este es el lugar correcto para construir un nuevo marco de interrupción con el puntero de pila existente, por lo que las cosas básicamente funcionaron bien con un marco de trampa 700 de aspecto extraño agregado en la parte superior (que tenía el ->nip incorrecto, por lo que no decodificar mensajes de error tampoco). Solucione este problema evitando el uso de etiquetas numéricas al saltar sobre macros no triviales. Antes: LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 Módulos NUMA PowerNV vinculados en: CPU: 0 PID: 88 Comm: sh No contaminado 5.15.0-rc2-00034-ge057cdade6e5 #2637 NIP: 7265677368657265 LR c00000000 006c0c8 CTR: c0000000000097f0 REGS: c0000000fffb3a50 TRAP: 0700 No contaminado MSR: 9000000000021031 CR: 00000700 XER: 20040000 CFAR: c0000000000098b0 IRQMASK: 0 GPR00: 0000006c964 c0000000fffb3cf0 c000000001513800 0000000000000000 GPR04: 0000000048ab0778 0000000042000000 0000000000000000 0000000000 001299 GPR08: 000001e447c718ec 0000000022424282 0000000000002710 c00000000006bee8 GPR12: 9000000000009033 c0000000016b0000 00000000000000b0 000 0000000000001 GPR16: 0000000000000000 0000000000000002 0000000000000000 0000000000000ff8 GPR20: 0000000000001fff 0000000000000007 0000000000000080 00007fff89d90158 GPR24: 0000000002000000 0000000002000000 0000000000000255 0000000000000300 GPR28 c0000000012700 00 0000000042000000 0000000048ab0778 c000000080647e80 NIP [7265677368657265] 0x7265677368657265 LR [c00000000006c0c8] /0xb10 Seguimiento de llamadas : [c0000000fffb3cf0] [c00000000000bdac] soft_nmi_common+0x13c/0x1d0 (no confiable) --- interrupción: 700 en decrementer_common_virt+0xb8/0x230 NIP: c0000000000098b8 LR: c00000000006c0 c8 CTR: c0000000000097f0 REGS: c0000000fffb3d60 TRAP: 0700 MSR no contaminado: 9000000000021031 CR: 22424282 XER: 20040000 CFAR: c0000000000098b0 IRQMASK: 0 GPR00: c00000000006c964 0000000000002400 c000000001513800 00000000 00000000 GPR04: 0000000048ab0778 0000000042000000 0000000000000000 0000000000001299 GPR08: 000001e447c718ec 0000000022424282 00000002710 c00000000006bee8 GPR12: 9000000000009033 c0000000016b0000 00000000000000b0 00000000000000001 GPR16: 0000000000000000 0000 000000000002 0000000000000000 0000000000000ff8 GPR20: 0000000000001fff 0000000000000007 00000000000000080 00007fff89d90158 GPR24: 000 0000000002000000 0000000000000255 0000000000000300 GPR28: c000000001270000 0000000042000000 0000000048ab0778 c000000080647e80 NIP [c0000000000098b8] decrementer_common_virt+0xb8/0x230 LR [c00000000006c0c8] ___do_page_fault+0x3f8/0xb10 --- interrupción: 700 Volcado de instrucciones: XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX ---[ final de seguimiento 6d28218e0cc3c949 ]--- Después: ------------[ cortar aquí ]-------- ---- ¡ERROR del kernel en arch/powerpc/kernel/exceptions-64s.S:491! Vaya: Excepción en modo kernel, sign: 5 [#1] LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 Módulos NUMA PowerNV vinculados en: CPU: 0 PID: 88 Comm: iniciar sesión No está contaminado 5.15.0-rc2-00034- ge057cdade6e5-dirty #2638 NIP: c0000000000098b8 LR: c00000000006bf04 CTR: c0000000000097f0 REGS: c0000000fffb3d60 TRAP: 0700 No contaminado MSR: 90000000000210 31 CR: 24482227 XER: 00040000 CFAR: c0000000000098b0 IRQMASK: 0 GPR00: c00000000006bf04 0000000000002400 c000000001513800 c000000001271868 GPR04: 00000000100f0d29 0000000042000000 0000000000000 007 0000000000000009 GPR08: 00000000100f0d29 0000000024482227 0000000000002710 c000000000181b3c GPR12: 9000000000009033 c000000001 6b0000 00000000100f0d29 c000000005b22f00 GPR16: 00000000ffff0000 0000000000000001 ---truncado---

*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

2024-05-21 CVE Reserved
2024-05-21 CVE Published
2024-05-22 EPSS Updated
2024-08-04 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CAPEC

References (4)

URL	Tag	Source
https://git.kernel.org/stable/c/0a882e28468f48ab3d9a36dde0a5723ea29ed1ed	Vuln. Introduced

URL	Date	SRC

URL	Date	SRC
https://git.kernel.org/stable/c/411b38fe68ba20a8bbe724b0939762c3f16e16ca	2021-10-13
https://git.kernel.org/stable/c/c835b3d1d6362b4a4ebb192da7e7fd27a0a45d01	2021-10-13
https://git.kernel.org/stable/c/3e607dc4df180b72a38e75030cb0f94d12808712	2021-10-07

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"				>= 5.3 < 5.10.73 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.3 < 5.10.73"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 5.3 < 5.14.12 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.3 < 5.14.12"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 5.3 < 5.15 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.3 < 5.15"		en		Affected