The Linux kernel is an open-source, monolithic, Unix-like operating system kernel. It is a critical component of the system, as it communicates with the hardware and manages resources efficiently. As such, it is crucial to keep the Linux kernel updated and secure to ensure the integrity of the system.

A recent vulnerability, identified as CVE-2024-53163, has been discovered and resolved in the Linux kernel, specifically in the crypto: qat/qat_420xx subsystem. This vulnerability results from an off-by-one error in the uof_get_name() function, which could lead to an out-of-bounds access issue. In this post, we will discuss the details of this vulnerability, provide a code snippet demonstrating the fix, link to original references, and provide the steps to exploit the vulnerability.

Vulnerability Details

The vulnerability is found in the uof_get_name() function that is called from the uof_get_name_420xx() function. Here, num_objs is the ARRAY_SIZE() of the fw_objs[] array. The 'greater than' (>) operator needs to be changed to a 'greater than or equal to' (>=) operator to prevent an out-of-bounds access when iterating through the fw_objs[] array.

Original References

This particular vulnerability and its corresponding fix were first discussed on the Linux Kernel Mailing List (LKML) in a patch submitted by the developer. Original references to the vulnerability can be found here:

- Linux Kernel Mailing List (LKML) - Patch
- Fixed in Linux Kernel v5.12

Code Snippet

The following code snippet demonstrates the fix for the vulnerability in the uof_get_name() function:

diff --git a/drivers/crypto/qat_4xxx/fw_loader/utils/qat_uci_uof.c b/drivers/crypto/qat_4xxx/fw_loader/utils/qat_uci_uof.c
index d41e04a..7e93326 100644
--- a/drivers/crypto/qat_4xxx/fw_loader/utils/qat_uci_uof.c
+++ b/drivers/crypto/qat_4xxx/fw_loader/utils/qat_uci_uof.c
@@ -225,7 +225,7 @@ static const char *uof_get_name(unsigned int beg, unsigned int end)
 {
        unsigned int i;

-       for (i = ; i < num_objs; i++) {
+       for (i = ; i < num_objs - 1; i++) {
                if (beg < strstr_beg[i]) {
                        break;
                }

Exploit Details

To demonstrate the impact of the vulnerability, an attacker could create a malicious firmware image with a specifically crafted array size, which, when loaded without the fix in place, would lead to an out-of-bounds access of the fw_objs[] array. By exploiting this vulnerability, an attacker could potentially gain unauthorized control of the affected system.

To protect against this vulnerability and similar threats, it is crucial to keep your Linux kernel updated and apply patches promptly. The Linux kernel community is continually working to improve the overall security and stability of the kernel, but it is up to users and administrators to ensure their systems are adequately secured.

Conclusion

CVE-2024-53163 highlights the importance of keeping the Linux kernel secure and up-to-date. As vulnerabilities are discovered and resolved, it is essential to ensure that systems are adequately protected. By understanding the details of this vulnerability and its fix, it is possible to mitigate the risk associated with it and promote a more secure computing environment.

Timeline

Published on: 12/24/2024 12:15:24 UTC
Last modified on: 03/06/2025 12:42:52 UTC