CVE-2021-47136

net: zero-initialize tc skb extension on allocation

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:

net: zero-initialize tc skb extension on allocation

Function skb_ext_add() doesn't initialize created skb extension with any
value and leaves it up to the user. However, since extension of type
TC_SKB_EXT originally contained only single value tc_skb_ext->chain its
users used to just assign the chain value without setting whole extension
memory to zero first. This assumption changed when TC_SKB_EXT extension was
extended with additional fields but not all users were updated to
initialize the new fields which leads to use of uninitialized memory
afterwards. UBSAN log:

[ 778.299821] UBSAN: invalid-load in net/openvswitch/flow.c:899:28
[ 778.301495] load of value 107 is not a valid value for type '_Bool'
[ 778.303215] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.12.0-rc7+ #2
[ 778.304933] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
[ 778.307901] Call Trace:
[ 778.308680] <IRQ>
[ 778.309358] dump_stack+0xbb/0x107
[ 778.310307] ubsan_epilogue+0x5/0x40
[ 778.311167] __ubsan_handle_load_invalid_value.cold+0x43/0x48
[ 778.312454] ? memset+0x20/0x40
[ 778.313230] ovs_flow_key_extract.cold+0xf/0x14 [openvswitch]
[ 778.314532] ovs_vport_receive+0x19e/0x2e0 [openvswitch]
[ 778.315749] ? ovs_vport_find_upcall_portid+0x330/0x330 [openvswitch]
[ 778.317188] ? create_prof_cpu_mask+0x20/0x20
[ 778.318220] ? arch_stack_walk+0x82/0xf0
[ 778.319153] ? secondary_startup_64_no_verify+0xb0/0xbb
[ 778.320399] ? stack_trace_save+0x91/0xc0
[ 778.321362] ? stack_trace_consume_entry+0x160/0x160
[ 778.322517] ? lock_release+0x52e/0x760
[ 778.323444] netdev_frame_hook+0x323/0x610 [openvswitch]
[ 778.324668] ? ovs_netdev_get_vport+0xe0/0xe0 [openvswitch]
[ 778.325950] __netif_receive_skb_core+0x771/0x2db0
[ 778.327067] ? lock_downgrade+0x6e0/0x6f0
[ 778.328021] ? lock_acquire+0x565/0x720
[ 778.328940] ? generic_xdp_tx+0x4f0/0x4f0
[ 778.329902] ? inet_gro_receive+0x2a7/0x10a0
[ 778.330914] ? lock_downgrade+0x6f0/0x6f0
[ 778.331867] ? udp4_gro_receive+0x4c4/0x13e0
[ 778.332876] ? lock_release+0x52e/0x760
[ 778.333808] ? dev_gro_receive+0xcc8/0x2380
[ 778.334810] ? lock_downgrade+0x6f0/0x6f0
[ 778.335769] __netif_receive_skb_list_core+0x295/0x820
[ 778.336955] ? process_backlog+0x780/0x780
[ 778.337941] ? mlx5e_rep_tc_netdevice_event_unregister+0x20/0x20 [mlx5_core]
[ 778.339613] ? seqcount_lockdep_reader_access.constprop.0+0xa7/0xc0
[ 778.341033] ? kvm_clock_get_cycles+0x14/0x20
[ 778.342072] netif_receive_skb_list_internal+0x5f5/0xcb0
[ 778.343288] ? __kasan_kmalloc+0x7a/0x90
[ 778.344234] ? mlx5e_handle_rx_cqe_mpwrq+0x9e0/0x9e0 [mlx5_core]
[ 778.345676] ? mlx5e_xmit_xdp_frame_mpwqe+0x14d0/0x14d0 [mlx5_core]
[ 778.347140] ? __netif_receive_skb_list_core+0x820/0x820
[ 778.348351] ? mlx5e_post_rx_mpwqes+0xa6/0x25d0 [mlx5_core]
[ 778.349688] ? napi_gro_flush+0x26c/0x3c0
[ 778.350641] napi_complete_done+0x188/0x6b0
[ 778.351627] mlx5e_napi_poll+0x373/0x1b80 [mlx5_core]
[ 778.352853] __napi_poll+0x9f/0x510
[ 778.353704] ? mlx5_flow_namespace_set_mode+0x260/0x260 [mlx5_core]
[ 778.355158] net_rx_action+0x34c/0xa40
[ 778.356060] ? napi_threaded_poll+0x3d0/0x3d0
[ 778.357083] ? sched_clock_cpu+0x18/0x190
[ 778.358041] ? __common_interrupt+0x8e/0x1a0
[ 778.359045] __do_softirq+0x1ce/0x984
[ 778.359938] __irq_exit_rcu+0x137/0x1d0
[ 778.360865] irq_exit_rcu+0xa/0x20
[ 778.361708] common_interrupt+0x80/0xa0
[ 778.362640] </IRQ>
[ 778.363212] asm_common_interrupt+0x1e/0x40
[ 778.364204] RIP: 0010:native_safe_halt+0xe/0x10
[ 778.365273] Code: 4f ff ff ff 4c 89 e7 e8 50 3f 40 fe e9 dc fe ff ff 48 89 df e8 43 3f 40 fe eb 90 cc e9 07 00 00 00 0f 00 2d 74 05 62 00 fb f4 <c3> 90 e9 07 00 00 00 0f 00 2d 64 05 62 00 f4 c3 cc cc 0f 1f 44 00
[ 778.369355] RSP: 0018:ffffffff84407e48 EFLAGS: 00000246
[ 778.370570] RAX
---truncated---

En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: net: inicialización cero de la extensión tc skb en la asignación La función skb_ext_add() no inicializa la extensión skb creada con ningún valor y lo deja en manos del usuario. Sin embargo, dado que la extensión de tipo TC_SKB_EXT originalmente contenía solo un valor único tc_skb_ext->chain, sus usuarios solían asignar simplemente el valor de la cadena sin establecer primero toda la memoria de extensión en cero. Esta suposición cambió cuando la extensión TC_SKB_EXT se amplió con campos adicionales, pero no todos los usuarios se actualizaron para inicializar los nuevos campos, lo que lleva al uso de memoria no inicializada posteriormente. Registro de UBSAN: [778.299821] UBSAN: carga no válida en net/openvswitch/flow.c:899:28 [778.301495] la carga del valor 107 no es un valor válido para el tipo '_Bool' [778.303215] CPU: 0 PID: 0 Comm : swapper/0 Not tainted 5.12.0-rc7+ #2 [ 778.304933] Nombre del hardware: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/ 2014 [778.307901] Seguimiento de llamadas: [778.308680] [778.309358] dump_stack+0xbb/0x107 [778.310307] ubsan_epilogue+0x5/0x40 [778.311167] __ubsan_handle_load_invalid_value.col d+0x43/0x48 [778.312454]? memset+0x20/0x40 [778.313230] ovs_flow_key_extract.cold+0xf/0x14 [openvswitch] [778.314532] ovs_vport_receive+0x19e/0x2e0 [openvswitch] [778.315749]? ovs_vport_find_upcall_portid+0x330/0x330 [openvswitch] [778.317188]? create_prof_cpu_mask+0x20/0x20 [778.318220]? arch_stack_walk+0x82/0xf0 [778.319153]? second_startup_64_no_verify+0xb0/0xbb [778.320399]? stack_trace_save+0x91/0xc0 [778.321362]? stack_trace_consume_entry+0x160/0x160 [778.322517]? lock_release+0x52e/0x760 [778.323444] netdev_frame_hook+0x323/0x610 [openvswitch] [778.324668]? ovs_netdev_get_vport+0xe0/0xe0 [openvswitch] [778.325950] __netif_receive_skb_core+0x771/0x2db0 [778.327067]? lock_downgrade+0x6e0/0x6f0 [778.328021]? lock_acquire+0x565/0x720 [778.328940]? generic_xdp_tx+0x4f0/0x4f0 [778.329902]? inet_gro_receive+0x2a7/0x10a0 [778.330914]? lock_downgrade+0x6f0/0x6f0 [778.331867]? udp4_gro_receive+0x4c4/0x13e0 [778.332876]? lock_release+0x52e/0x760 [778.333808]? dev_gro_receive+0xcc8/0x2380 [778.334810]? lock_downgrade+0x6f0/0x6f0 [ 778.335769] __netif_receive_skb_list_core+0x295/0x820 [ 778.336955] ? proceso_backlog+0x780/0x780 [778.337941]? mlx5e_rep_tc_netdevice_event_unregister+0x20/0x20 [mlx5_core] [778.339613]? seqcount_lockdep_reader_access.constprop.0+0xa7/0xc0 [778.341033]? kvm_clock_get_cycles+0x14/0x20 [ 778.342072] netif_receive_skb_list_internal+0x5f5/0xcb0 [ 778.343288] ? __kasan_kmalloc+0x7a/0x90 [778.344234]? mlx5e_handle_rx_cqe_mpwrq+0x9e0/0x9e0 [mlx5_core] [778.345676]? mlx5e_xmit_xdp_frame_mpwqe+0x14d0/0x14d0 [mlx5_core] [778.347140]? __netif_receive_skb_list_core+0x820/0x820 [778.348351]? mlx5e_post_rx_mpwqes+0xa6/0x25d0 [mlx5_core] [778.349688]? napi_gro_flush+0x26c/0x3c0 [ 778.350641] napi_complete_done+0x188/0x6b0 [ 778.351627] mlx5e_napi_poll+0x373/0x1b80 [mlx5_core] [ 778.352853] __napi_poll+0x9f/0x510 [778.353704] ? mlx5_flow_namespace_set_mode+0x260/0x260 [mlx5_core] [778.355158] net_rx_action+0x34c/0xa40 [778.356060]? napi_threaded_poll+0x3d0/0x3d0 [778.357083]? sched_clock_cpu+0x18/0x190 [778.358041]? __common_interrupt+0x8e/0x1a0 [ 778.359045] __do_softirq+0x1ce/0x984 [ 778.359938] __irq_exit_rcu+0x137/0x1d0 [ 778.360865] irq_exit_rcu+0xa/0x20 [ 778.36170 8] interrupción_común+0x80/0xa0 [ 778.362640] [ 778.363212] asm_interrupción_común+0x1e /0x40 [ 778.364204] RIP: 0010:native_safe_halt+0xe/0x10 [ 778.365273] Código: 4f ff ff ff 4c 89 e7 e8 50 3f 40 fe e9 dc fe ff ff 48 89 df e8 43 3f 40 fe eb 90 cc e 9 07 00 00 00 0f 00 2d 74 05 62 00 fb f4 90 e9 07 00 00 00 0f 00 2d 64 05 62 00 f4 c3 cc cc 0f 1f 44 00 [ 778.369355] RSP: 0018:ffffffff84407 e48 EFLAGS: 00000246 [778.370570] RAX ---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

2024-03-04 CVE Reserved
2024-03-25 CVE Published
2024-03-26 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/038ebb1a713d114d54dbf14868a73181c0c92758	Vuln. Introduced
https://git.kernel.org/stable/c/7154bda4cfc1f41b339121475d2b0234141f3492	Vuln. Introduced

URL	Date	SRC

URL	Date	SRC
https://git.kernel.org/stable/c/ac493452e937b8939eaf2d24cac51a4804b6c20e	2021-06-03
https://git.kernel.org/stable/c/86ab133b695ed7ba1f8786b12f4ca43137ad8c18	2021-06-03
https://git.kernel.org/stable/c/9453d45ecb6c2199d72e73c993e9d98677a2801b	2021-05-25

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"				>= 5.9 < 5.10.42 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.9 < 5.10.42"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 5.9 < 5.12.9 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.9 < 5.12.9"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 5.9 < 5.13 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.9 < 5.13"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				5.7.15 Search vendor "Linux" for product "Linux Kernel" and version "5.7.15"		en		Affected