3.18

CVSS 7.0 - HIGH

Attack vector

LOCAL

Attack complexity

HIGH

Privileges required

NONE

Confidentiality impact

HIGH

Integrity impact

HIGH

Availability impact

HIGH

local

high complexity

linux

CWE-131

exploit available

NVD

Published: 2017-04-07

Updated: 2024-11-21

Summary

An elevation of privilege vulnerability in the Broadcom Wi-Fi driver could enable a local malicious application to execute arbitrary code within the context of the kernel. This issue is rated as High because it first requires compromising a privileged process. Product: Android. Versions: Kernel-3.10, Kernel-3.18. Android ID: A-34198729. References: B-RB#110666.

Vulnerable Configurations

Part	Description	Count
OS	Linux Linux Linux Kernel 3.10 Linux Linux Kernel 3.18	2

Common Weakness Enumeration (CWE)

CWE-131 - Incorrect Calculation of Buffer Size

Common Attack Pattern Enumeration and Classification (CAPEC)

Overflow Buffers
Buffer Overflow attacks target improper or missing bounds checking on buffer operations, typically triggered by input injected by an attacker. As a consequence, an attacker is able to write past the boundaries of allocated buffer regions in memory, causing a program crash or potentially redirection of execution as per the attackers' choice.
Buffer Overflow via Parameter Expansion
In this attack, the target software is given input that the attacker knows will be modified and expanded in size during processing. This attack relies on the target software failing to anticipate that the expanded data may exceed some internal limit, thereby creating a buffer overflow.

Exploit-Db

description	Broadcom Wi-Fi SoC - 'dhd_handle_swc_evt' Heap Overflow. CVE-2017-0569. Remote exploit for Hardware platform
file	exploits/hardware/remote/41808.txt
id	EDB-ID:41808
last seen	2017-04-04
modified	2017-04-04
platform	hardware
port
published	2017-04-04
reporter	Exploit-DB
source	https://www.exploit-db.com/download/41808/
title	Broadcom Wi-Fi SoC - 'dhd_handle_swc_evt' Heap Overflow
type	remote

Seebug

bulletinFamily	exploit
description	roadcom produces Wi-Fi HardMAC SoCs which are used to handle the PHY and MAC layer processing. These chips are present in both mobile devices and Wi-Fi routers, and are capable of handling many Wi-Fi related events without delegating to the host OS. On Android devices, the "bcmdhd" driver is used in order to communicate with the Wi-Fi SoC (also referred to as "dongle"). When the dongle wishes to notify the host OS of an event, it does so by encoding a special "packet" and transmitting it to the host. These packets have an ether type of 0x886C (referred to as ETHER_TYPE_BRCM), and do not contain actual packet data, but rather encapsulate information about events which must be handled by the driver. After reading packets from the SDIO interface, the "bcmdhd" driver calls the function "dhd_rx_frame" to handle each of the received frames. If a frame has the special Broadcom ether type, it is passed on to an internal handling function, "dhd_wl_host_event". This function inspects the event code, and passes it onto the registered handlers for the given event type. The function "wl_notify_gscan_event" is the registered handler for events of the following types: ``` -WLC_E_PFN_BEST_BATCHING -WLC_E_PFN_SCAN_COMPLETE -WLC_E_PFN_GSCAN_FULL_RESULT -WLC_E_PFN_SWC -WLC_E_PFN_BSSID_NET_FOUND -WLC_E_PFN_BSSID_NET_LOST -WLC_E_PFN_SSID_EXT -WLC_E_GAS_FRAGMENT_RX ``` (for reference, see "wl_init_event_handler") Specifically, when the event code "WLC_E_PFN_SWC" is received, the gscan handler function calls "dhd_handle_swc_evt" in order to process the event's data, like so: ``` 1. void * dhd_handle_swc_evt(dhd_pub_t dhd, const void event_data, int send_evt_bytes) 2. { 3. ... 4. wl_pfn_swc_results_t results = (wl_pfn_swc_results_t )event_data; 5. ... 6. gscan_params = &(_pno_state->pno_params_arr[INDEX_OF_GSCAN_PARAMS].params_gscan); 7. ... 8. if (!params->results_rxed_so_far) { 9. if (!params->change_array) { 10. params->change_array = (wl_pfn_significant_net_t ) 11. kmalloc(sizeof(wl_pfn_significant_net_t) * results->total_count, GFP_KERNEL); 12. ... 13. } 14. } 15. ... 16. change_array = &params->change_array[params->results_rxed_so_far]; 17. memcpy(change_array, results->list, sizeof(wl_pfn_significant_net_t) * results->pkt_count); 18. params->results_rxed_so_far += results->pkt_count; 19. ... 20. } ``` (where "event_data" is the arbitrary data encapsulated in the event passed in from the dongle) When the function above is first invoked, the value of "`params->change_array`" is NULL. An attacker controlling the dongle may send a crafted `WLC_E_PFN_SWC` event, with the following values: ``` - results->total_count = SMALL_VALUE - result->pkt_count = LARGE_VALUE ``` Since the function fails to verify that "pkt_count" is not larger than "total_count", this would cause the allocated buffer (lines 10-11) to be smaller than the size used in the memcpy operation (line 17), thus overflowing the buffer. I've been able to statically verify these issues on the "bcmdhd-3.10" driver, and in the corresponding "bcmdhd" driver on the Nexus 6P's kernel (angler).
id	SSV:92900
last seen	2017-11-19
modified	2017-04-05
published	2017-04-05
reporter	Root
title	Broadcom: Heap overflow in "dhd_handle_swc_evt"(CVE-2017-0569)