libbpf: Handle size overflow for ringbuf mmap

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: libbpf: Handle size overflow for ringbuf mmap The maximum size of ringbuf is 2GB on x86-64 host, so 2 * max_entries will overflow u32 when mapping producer page and data pages. Only casting max_entries to size_t is not enough, because for 32-bits application on 64-bits kernel the size of read-only mmap region also could overflow size_t. So fixing it by casting the size of read-only mmap region into a __u64 and checking whether or not there will be overflow during mmap.

References

• https://git.kernel.org/stable/c/8a549ab6724520aa3c07f47e0eba820293551490
• https://git.kernel.org/stable/c/0140e079a42064680394fff1199a7b5483688dec
• https://git.kernel.org/stable/c/535a25ab4f9a45f74ba38ab71de95e97474922ed
• https://git.kernel.org/stable/c/927cbb478adf917e0a142b94baa37f06279cc466