Missing Lock Vulnerability in Linux Kernel
Summary
GSD-2021-1002083: misc: fastrpc: Add missing lock before accessing find_vma(). Affects Kernel versions >= 80f3afd72bd4149c57daf852905476b43bb47647, < d22592f1fd8d4bf54fa1cc0ef9122c983d82f30a. No fix is published. How to fix ↓
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Background
The Linux Kernel is the core component of the Linux operating system, responsible for managing system resources and providing essential services. It is a widely used open-source package that powers numerous devices and servers. The vulnerability in question, identified as GSD-2021-1002083, affects the Linux Kernel and specifically the 'misc: fastrpc' module. This module is responsible for facilitating fast remote procedure calls (RPC) within the kernel. The vulnerability arises from a missing lock before accessing the 'find_vma()' function, which can lead to potential security risks.
Vulnerability Detail
The missing lock vulnerability in the 'misc: fastrpc' module of the Linux Kernel allows for unauthorized access to the 'find_vma()' function. This can result in various security issues, including potential information disclosure, privilege escalation, or denial of service attacks. The vulnerability was introduced in version v5.2 of the Linux Kernel and has been fixed in version v5.14.14. The impact and attack plausibility of this vulnerability have not been proven yet.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
As a workaround, users can apply the patch provided in the fix commit (d22592f1fd8d4bf54fa1cc0ef9122c983d82f30a) manually. Here is an example of the patch:
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -123,6 +123,7 @@ static int fastrpc_mmap(struct file *filp, struct vm_area_struct *vma)
struct fastrpc_session_ctx *session_ctx;
struct fastrpc_buf *buf;
struct fastrpc_user *fl;
+ mutex_lock(&fastrpc_mutex);
fl = fastrpc_get_user(filp);
if (!fl)
@@ -137,6 +138,7 @@ static int fastrpc_mmap(struct file *filp, struct vm_area_struct *vma)
goto err;
}
+ mutex_unlock(&fastrpc_mutex);
return 0;
err:
Conclusion
The missing lock vulnerability in the 'misc: fastrpc' module of the Linux Kernel can pose potential security risks. It is crucial to update the Linux Kernel to version v5.14.14 or later to mitigate this vulnerability. Users can also apply the provided patch as a temporary workaround. For further support and assistance in vulnerability remediation, please contact DevNack.com.
See every vulnerability recorded for Kernel →
FAQ
The impact of this vulnerability can vary depending on the specific usage scenario. It could potentially lead to information disclosure, privilege escalation, or denial of service attacks.
You can use the Vulert Playground (https://vulert.com/scanner) to check if your system is affected by this vulnerability. Simply upload your package-lock.json file, and Vulert will analyze it for any open-source vulnerabilities, including this one.
Yes, a workaround is available. Users can manually apply the provided patch to fix the missing lock issue in the 'misc: fastrpc' module. The patch is available in the fix commit (d22592f1fd8d4bf54fa1cc0ef9122c983d82f30a).
The recommended solution is to update the Linux Kernel to version v5.14.14 or later. This update includes the necessary fix for the missing lock vulnerability in the 'misc: fastrpc' module.
You can find more information about this vulnerability, including the fix commit and affected versions, in the vulnerability database entry: https://github.com/cloudsecurityalliance/gsd-database/blob/main/2021/1002xxx/GSD-2021-1002083.json
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