Attacker Value
Unknown
(0 users assessed)
Exploitability
Unknown
(0 users assessed)
User Interaction
None
Privileges Required
Low
Attack Vector
Local
0

CVE-2021-47065

Disclosure Date: February 29, 2024 •
CVE-2021-47065 CVSS v3 Base Score: 7.8
Add MITRE ATT&CK tactics and techniques that apply to this CVE.

Description

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

rtw88: Fix array overrun in rtw_get_tx_power_params()

Using a kernel with the Undefined Behaviour Sanity Checker (UBSAN) enabled, the
following array overrun is logged:

================================================================================
UBSAN: array-index-out-of-bounds in /home/finger/wireless-drivers-next/drivers/net/wireless/realtek/rtw88/phy.c:1789:34
index 5 is out of range for type ‘u8 [5]’
CPU: 2 PID: 84 Comm: kworker/u16:3 Tainted: G O 5.12.0-rc5-00086-gd88bba47038e-dirty #651
Hardware name: TOSHIBA TECRA A50-A/TECRA A50-A, BIOS Version 4.50 09/29/2014
Workqueue: phy0 ieee80211_scan_work [mac80211]
Call Trace:
dump_stack+0x64/0x7c
ubsan_epilogue+0x5/0x40
__ubsan_handle_out_of_bounds.cold+0x43/0x48
rtw_get_tx_power_params+0x83a/drivers/net/wireless/realtek/rtw88/0xad0 [rtw_core]
? rtw_pci_read16+0x20/0x20 [rtw_pci]
? check_hw_ready+0x50/0x90 [rtw_core]
rtw_phy_get_tx_power_index+0x4d/0xd0 [rtw_core]
rtw_phy_set_tx_power_level+0xee/0x1b0 [rtw_core]
rtw_set_channel+0xab/0x110 [rtw_core]
rtw_ops_config+0x87/0xc0 [rtw_core]
ieee80211_hw_config+0x9d/0x130 [mac80211]
ieee80211_scan_state_set_channel+0x81/0x170 [mac80211]
ieee80211_scan_work+0x19f/0x2a0 [mac80211]
process_one_work+0x1dd/0x3a0
worker_thread+0x49/0x330
? rescuer_thread+0x3a0/0x3a0
kthread+0x134/0x150
? kthread_create_worker_on_cpu+0x70/0x70

ret_from_fork+0x22/0x30

The statement where an array is being overrun is shown in the following snippet:

if (rate <= DESC_RATE11M)
	tx_power = pwr_idx_2g->cck_base[group];
else

====> tx_power = pwr_idx_2g->bw40_base[group];

The associated arrays are defined in main.h as follows:

struct rtw_2g_txpwr_idx {

u8 cck_base[6];
u8 bw40_base[5];
struct rtw_2g_1s_pwr_idx_diff ht_1s_diff;
struct rtw_2g_ns_pwr_idx_diff ht_2s_diff;
struct rtw_2g_ns_pwr_idx_diff ht_3s_diff;
struct rtw_2g_ns_pwr_idx_diff ht_4s_diff;

};

The problem arises because the value of group is 5 for channel 14. The trivial
increase in the dimension of bw40_base fails as this struct must match the layout of
efuse. The fix is to add the rate as an argument to rtw_get_channel_group() and set
the group for channel 14 to 4 if rate <= DESC_RATE11M.

This patch fixes commit fa6dfe6bff24 (“rtw88: resolve order of tx power setting routines”)

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CVSS V3 Severity and Metrics
Base Score:
7.8 High
Impact Score:
5.9
Exploitability Score:
1.8
Vector:
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack Vector (AV):
Local
Attack Complexity (AC):
Low
Privileges Required (PR):
Low
User Interaction (UI):
None
Scope (S):
Unchanged
Confidentiality (C):
High
Integrity (I):
High
Availability (A):
High

General Information

Offensive Application
Unknown
Utility Class
Unknown
Ports
Unknown
OS
Unknown
Vulnerable Versions
Linux 6b5aa0cf321c
Linux not down converted
Prerequisites
Unknown
Discovered By
Unknown
PoC Author
Unknown
Metasploit Module
Unknown
Reporter
Unknown

Vendors

  • linux

Products

  • linux kernel
Technical Analysis