CVE-2022-49853

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

net: macvlan: fix memory leaks of macvlan_common_newlink

kmemleak reports memory leaks in macvlan_common_newlink, as follows:

ip link add link eth0 name .. type macvlan mode source macaddr add

kmemleak reports:

unreferenced object 0xffff8880109bb140 (size 64): comm ip, pid 284, jiffies 4294986150 (age 430.108s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 b8 aa 5a 12 80 88 ff ff ……….Z….. 80 1b fa 0d 80 88 ff ff 1e ff ac af c7 c1 6b 6b …………..kk backtrace: [] kmem_cache_alloc_trace+0x1c7/0x300 [] macvlan_hash_add_source+0x45/0xc0 [] macvlan_changelink_sources+0xd7/0x170 [] macvlan_common_newlink+0x38c/0x5a0 [] macvlan_newlink+0xe/0x20 [] __rtnl_newlink+0x7af/0xa50 [] rtnl_newlink+0x48/0x70 …

In the scenario where the macvlan mode is configured as source, macvlan_changelink_sources() will be execured to reconfigure list of remote source mac addresses, at the same time, if register_netdevice() return an error, the resource generated by macvlan_changelink_sources() is not cleaned up.

Using this patch, in the case of an error, it will execute macvlan_flush_sources() to ensure that the resource is cleaned up.

Weakness

The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory.

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/21d3a8b6a1e39e7529ce9de07316ee13a63f305b
• https://git.kernel.org/stable/c/23569b5652ee8e8e55a12f7835f59af6f3cefc30
• https://git.kernel.org/stable/c/685e73e3f7a9fb75cbf049a9d0b7c45cc6b57b2e
• https://git.kernel.org/stable/c/956e0216a19994443c90ba2ea6b0b284c9c4f9cb
• https://git.kernel.org/stable/c/9ea003c4671b2fc455320ecf6d4a43b0a3c1878a
• https://git.kernel.org/stable/c/9f288e338be206713d79b29144c27fca4503c39b
• https://git.kernel.org/stable/c/a81b44d1df1f07f00c0dcc0a0b3d2fa24a46289e
• https://git.kernel.org/stable/c/a8d67367ab33604326cc37ab44fd1801bf5691ba