CVE-2022-23086: A Deep Dive into Exploiting Handlers for *_CFG_PAGE Read/Write IOCTLs in MPR, MPS, and MPT Drivers

In this post, we will be discussing an important vulnerability, CVE-2022-23086, that affects the Handlers for *_CFG_PAGE read/write IOCTLs in popular mpr, mps, and mpt drivers. We will explore the technical details of the vulnerability, including the code snippet responsible for the vulnerability and the potential exploit scenario. Moreover, we will provide links to the original references for a better understanding of the issue.

Vulnerability Details

The vulnerability exists in the *_CFG_PAGE handlers, which are responsible for reading and writing configuration pages in the mpr, mps, and mpt drivers. The problem lies in the implementation of the handlers, specifically in their buffer allocation and copy procedures.

The handlers would allocate a buffer of a caller-specified size while copying a fixed-size header to it. However, if the specified size is too small, other heap content would be overwritten, leading to a potential vulnerability.

Here's a simplified code snippet that demonstrates the vulnerability

void vulnerable_handler(unsigned long arg) {
    size_t buffer_size = *((size_t *) arg);
    void *buffer = kmalloc(buffer_size, GFP_KERNEL);
    struct fixed_size_header header;
    memcpy(buffer, &header, sizeof(header));

    if (buffer_size < sizeof(header)) {
        // Heap content can be overwritten
    }
}

Exploit Details

The vulnerability can be exploited by an attacker who has access to the mpr, mps or mpt device node. If the attacker can overwrite heap data, they can potentially escalate their privileges. It's important to note that the device node is only accessible to root users and members of the operator group.

Here's a possible exploit scenario, given the attacker has access

1. An attacker specifies a buffer size smaller than the fixed size header when making a call to the vulnerable handler.
2. Due to the smaller buffer size, the memcpy function copies the header, overwriting other heap content.
3. The attacker leverages the overwritten heap content to escalate their privileges, potentially gaining root access or control over other system processes.

Original References

1. Official CVE-2022-23086 vulnerability details
2. Link to MPR Driver
3. Link to MPS Driver
4. Link to MPT Driver

Conclusion

In conclusion, CVE-2022-23086 is a critical vulnerability affecting Handlers for *_CFG_PAGE read/write IOCTLs in mpr, mps, and mpt drivers. By overwriting heap data, an attacker with access to the device node can potentially escalate their privileges. It is crucial for developers to ensure proper buffer allocation and validation to prevent such vulnerabilities. Be sure to keep a close eye on any updates related to this issue and apply security patches as they become available.

Timeline

Published on: 02/15/2024 05:15:09 UTC
Last modified on: 08/28/2024 20:35:00 UTC