CVE-2022-50046

In the Linux kernel, the following vulnerability has been resolved:

net/sunrpc: fix potential memory leaks in rpc_sysfs_xprt_state_change()

The issue happens on some error handling paths. When the function fails to grab the object xprt, it simply returns 0, forgetting to decrease the reference count of another object xps, which is increased by rpc_sysfs_xprt_kobj_get_xprt_switch(), causing refcount leaks. Also, the function forgets to check whether xps is valid before using it, which may result in NULL-dereferencing issues.

Fix it by adding proper error handling code when either xprt or xps is NULL.

Weakness

The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.

Affected Software

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

• https://git.kernel.org/stable/c/76fbeb1662b1c56514325118a07fba74dc4c79fe
• https://git.kernel.org/stable/c/bfc48f1b0505ffcb03a6d749139b7577d6b81ae0
• https://git.kernel.org/stable/c/c0434f0e058648649250b8ed6078b66d773de723