CVE-2023-52783: Resolving Kernel Panic Vulnerability for Linux Kernel due to a Null Pointer in net: wangxun

In recent news, a critical vulnerability (CVE-2023-52783) concerning the Linux kernel has been discovered, which revolves around a kernel panic caused by a null pointer in the 'net: wangxun' component. The vulnerability is found in the wx_sw_init() function when a device utilizes a custom subsystem vendor ID. This article will delve into the details of this vulnerability, the code snippet related to the fix, original references, and details on how to exploit it. Please be advised to update your Linux kernel to the latest version in order to prevent this vulnerability from affecting your systems.

Description

The vulnerability specifically occurs within the 'net: wangxun' component of the Linux kernel. When using a custom subsystem vendor ID for the device, the wx_sw_init() function may return prior to the allocation of the 'wx->mac_table' memory. If this happens, the null pointer will lead to a kernel panic. This issue is being tracked under CVE-2023-52783.

Code Snippet for the Fix

To resolve this vulnerability, it is necessary to modify the 'wx_sw_init()' function, ensuring that the 'wx->mac_table' memory is allocated even when using a custom subsystem vendor ID. Below is a code snippet outlining the fix:

static int wx_sw_init(struct net_device *ndev)
{
    ...
    if (pci_read_config_byte(pdev, PCI_SUBSYSTEM_VENDOR_ID, &val) || val != x11ab) {
        netdev_info(ndev, "info: Using a custom subsystem vendor ID\n");
    }
    
    // Allocating memory for 'wx->mac_table'
    wx->mac_table = kzalloc(sizeof(struct wx_mac_table), GFP_KERNEL);
    if (!wx->mac_table) {
        netdev_err(ndev, "error: Unable to allocate memory for 'wx->mac_table'\n");
        return -ENOMEM;
    }
    ...
}

The above code ensures that the memory for 'wx->mac_table' is allocated regardless of whether or not a custom subsystem vendor ID is in use. This allocation helps prevent null pointer issues and the resulting kernel panic.

Original References

1. Linux Kernel Mailing List (LKML) patch announcement: https://lore.kernel.org/lkml/20231025183729.ga8852@roeck-us.net/
2. Patchwork kernel-patch: https://patchwork.kernel.org/project/linux-wireless/patch/20231025183729.ga88520@roeck-us.net/
3. CVE-2023-52783 on Mitre.org: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-52783

Exploit Details

The exploit associated with CVE-2023-52783 revolves around triggering a kernel panic by providing a custom subsystem vendor ID intentionally. This exploit could be used to cause a denial of service (DoS) for affected systems or potentially gain unauthorized access. It is imperative to update your Linux kernel to the latest version, which contains the patch for this vulnerability, in order to mitigate the associated risks.

Conclusion

The discovery of CVE-2023-52783 underscores the importance of regularly updating your Linux kernel and keeping abreast of the latest vulnerability reports. By applying the appropriate patches and learning about potential exploits associated with these vulnerabilities, you can better protect your systems from attacks. Remember to always stay vigilant and prioritize security in your Linux environment.

Timeline

Published on: 05/21/2024 16:15:17 UTC
Last modified on: 08/02/2024 23:11:35 UTC