CVE-2021-46947

  1. OpenCVE
  2. Vulnerabilities (CVE)
  3. CVE-2021-46947
In the Linux kernel, the following vulnerability has been resolved: sfc: adjust efx->xdp_tx_queue_count with the real number of initialized queues efx->xdp_tx_queue_count is initially initialized to num_possible_cpus() and is later used to allocate and traverse efx->xdp_tx_queues lookup array. However, we may end up not initializing all the array slots with real queues during probing. This results, for example, in a NULL pointer dereference, when running "# ethtool -S <iface>", similar to below [2570283.664955][T4126959] BUG: kernel NULL pointer dereference, address: 00000000000000f8 [2570283.681283][T4126959] #PF: supervisor read access in kernel mode [2570283.695678][T4126959] #PF: error_code(0x0000) - not-present page [2570283.710013][T4126959] PGD 0 P4D 0 [2570283.721649][T4126959] Oops: 0000 [#1] SMP PTI [2570283.734108][T4126959] CPU: 23 PID: 4126959 Comm: ethtool Tainted: G O 5.10.20-cloudflare-2021.3.1 #1 [2570283.752641][T4126959] Hardware name: <redacted> [2570283.781408][T4126959] RIP: 0010:efx_ethtool_get_stats+0x2ca/0x330 [sfc] [2570283.796073][T4126959] Code: 00 85 c0 74 39 48 8b 95 a8 0f 00 00 48 85 d2 74 2d 31 c0 eb 07 48 8b 95 a8 0f 00 00 48 63 c8 49 83 c4 08 83 c0 01 48 8b 14 ca <48> 8b 92 f8 00 00 00 49 89 54 24 f8 39 85 a0 0f 00 00 77 d7 48 8b [2570283.831259][T4126959] RSP: 0018:ffffb79a77657ce8 EFLAGS: 00010202 [2570283.845121][T4126959] RAX: 0000000000000019 RBX: ffffb799cd0c9280 RCX: 0000000000000018 [2570283.860872][T4126959] RDX: 0000000000000000 RSI: ffff96dd970ce000 RDI: 0000000000000005 [2570283.876525][T4126959] RBP: ffff96dd86f0a000 R08: ffff96dd970ce480 R09: 000000000000005f [2570283.892014][T4126959] R10: ffffb799cd0c9fff R11: ffffb799cd0c9000 R12: ffffb799cd0c94f8 [2570283.907406][T4126959] R13: ffffffffc11b1090 R14: ffff96dd970ce000 R15: ffffffffc11cd66c [2570283.922705][T4126959] FS: 00007fa7723f8740(0000) GS:ffff96f51fac0000(0000) knlGS:0000000000000000 [2570283.938848][T4126959] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [2570283.952524][T4126959] CR2: 00000000000000f8 CR3: 0000001a73e6e006 CR4: 00000000007706e0 [2570283.967529][T4126959] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [2570283.982400][T4126959] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [2570283.997308][T4126959] PKRU: 55555554 [2570284.007649][T4126959] Call Trace: [2570284.017598][T4126959] dev_ethtool+0x1832/0x2830 Fix this by adjusting efx->xdp_tx_queue_count after probing to reflect the true value of initialized slots in efx->xdp_tx_queues.

5.5 /10

CVSS v3 : MEDIUM

V3 Legend

Vector :

Exploitability : 1.8 / Impact : 3.6

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References
Link Resource
https://git.kernel.org/stable/c/99ba0ea616aabdc8e26259fd722503e012199a76 Patch
https://git.kernel.org/stable/c/ebeac958b690123a0b40aa61f688f2f170035fad Patch
Configurations

Configuration 1 (hide)

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
History

10 Apr 2024, 20:00

Type Values Removed Values Added
References () https://git.kernel.org/stable/c/99ba0ea616aabdc8e26259fd722503e012199a76 - () https://git.kernel.org/stable/c/99ba0ea616aabdc8e26259fd722503e012199a76 - Patch
References () https://git.kernel.org/stable/c/ebeac958b690123a0b40aa61f688f2f170035fad - () https://git.kernel.org/stable/c/ebeac958b690123a0b40aa61f688f2f170035fad - Patch
CPE cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
CVSS v2 : unknown
v3 : unknown 		v2 : unknown
v3 : 5.5
CWE CWE-476
First Time Linux linux Kernel
Linux
Summary
  • (es) En el kernel de Linux, se resolvió la siguiente vulnerabilidad: sfc: ajuste efx-&gt;xdp_tx_queue_count con el número real de colas inicializadas. efx-&gt;xdp_tx_queue_count se inicializa inicialmente en num_possible_cpus() y luego se usa para asignar y recorrer la búsqueda de efx-&gt;xdp_tx_queues formación. Sin embargo, es posible que terminemos sin inicializar todas las ranuras de la matriz con colas reales durante el sondeo. Esto da como resultado, por ejemplo, una desreferencia del puntero NULL, cuando se ejecuta "# ethtool -S ", similar a lo siguiente [2570283.664955][T4126959] ERROR: desreferencia del puntero NULL del kernel, dirección: 000000000000000f8 [2570283.681283][T4126959] # PF: acceso de lectura de supervisor en modo kernel [2570283.695678][T4126959] #PF: error_code(0x0000) - página no presente [2570283.710013][T4126959] PGD 0 P4D 0 [2570283.721649][T4126959] Ups: 0000 [# 1]MPD PTI [2570283.734108][T4126959] CPU: 23 PID: 4126959 Comunicaciones: ethtool Contaminado: GO 5.10.20-cloudflare-2021.3.1 #1 [2570283.752641][T4126959] Nombre de hardware: [2570283.78140 8][T4126959] QEPD: 0010:efx_ethtool_get_stats+0x2ca/0x330 [sfc] [2570283.796073][T4126959] Código: 00 85 c0 74 39 48 8b 95 a8 0f 00 00 48 85 d2 74 2d 31 c0 eb 07 48 8b 95 a8 0f 00 00 48 63 c8 49 83 c4 08 83 c0 01 48 8b 14 ca &lt;48&gt; 8b 92 f8 00 00 00 49 89 54 24 f8 39 85 a0 0f 00 00 77 d7 48 8b [2570283.831259][T4126959] RSP: 0018:ff ffb79a77657ce8 EFLAGS: 00010202 [2570283.845121 ][T4126959] RAX: 0000000000000019 RBX: ffffb799cd0c9280 RCX: 0000000000000018 [2570283.860872][T4126959] RDX: 0000000000000000 RSI: ffff96dd 970ce000 RDI: 0000000000000005 [2570283.876525][T4126959] RBP: ffff96dd86f0a000 R08: ffff96dd970ce480 R09: 000000000000005f [2570283.892014][T4 126959]R10 : ffffb799cd0c9fff R11: ffffb799cd0c9000 R12: ffffb799cd0c94f8 [2570283.907406][T4126959] R13: ffffffffc11b1090 R14: ffff96dd970ce000 R15: ffffffffc11cd66 c [2570283.922705][T4126959] FS: 00007fa7723f8740(0000) GS:ffff96f51fac0000(0000) knlGS:00000000000000000 [2570283.938848][T4126959] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [2570283.952524][T4126959] CR2: 000000000000000f8 CR3: 0000001a73e6e006 CR4: 00000000007706 e0 [2570283.967529][T4126959] DR0: 00000000000000000 DR1: 0000000000000000 DR2: 00000000000000000 [2570283.982400][T4126959] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [2570283.997308][T4126959] PKRU: 55555554 [2570284.007649][T4126959] Seguimiento de llamadas: [257 0284.017598][T4126959] dev_ethtool+0x1832/0x2830 Solucione este problema ajustando efx-&gt;xdp_tx_queue_count después de sondear para reflejar el verdadero valor de las ranuras inicializadas en efx-&gt;xdp_tx_queues.

27 Feb 2024, 19:04

Type Values Removed Values Added
New CVE
Information

Published : 2024-02-27 19:04

Updated : 2024-04-10 20:00

NVD link : CVE-2021-46947

Mitre link : CVE-2021-46947

CVE.ORG link : CVE-2021-46947

JSON object : View

Products Affected

linux

  • linux_kernel
CWE
CWE-476

NULL Pointer Dereference