The do_fork function in Linux 2.4.x before 2.4.26, and 2.6.x before 2.6.6, does not properly decrement the mm_count counter when an error occurs after the mm_struct for a child process has been activated, which triggers a memory leak that allows local users to cause a denial of service (memory exhaustion) via the clone (CLONE_VM) system call.
Weakness
The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory.
Affected Software
| Name |
Vendor |
Start Version |
End Version |
| Linux_kernel |
Linux |
2.4.0 (including) |
2.4.26 (excluding) |
| Linux_kernel |
Linux |
2.6.0 (including) |
2.6.6 (excluding) |
Potential Mitigations
- Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone.
- For example, glibc in Linux provides protection against free of invalid pointers.
- When using Xcode to target OS X or iOS, enable automatic reference counting (ARC) [REF-391].
- To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std::auto_ptr (defined by ISO/IEC ISO/IEC 14882:2003), std::shared_ptr and std::unique_ptr (specified by an upcoming revision of the C++ standard, informally referred to as C++ 1x), or equivalent solutions such as Boost.
References