cifs: fix underflow in parse_server_interfaces()

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: cifs: fix underflow in parse_server_interfaces() In this loop, we step through the buffer and after each item we check if the size_left is greater than the minimum size we need. However, the problem is that "bytes_left" is type ssize_t while sizeof() is type size_t. That means that because of type promotion, the comparison is done as an unsigned and if we have negative bytes left the loop continues instead of ending.

References

• https://git.kernel.org/stable/c/7190353835b4a219abb70f90b06cdcae97f11512
• https://git.kernel.org/stable/c/f7ff1c89fb6e9610d2b01c1821727729e6609308
• https://git.kernel.org/stable/c/df2af9fdbc4ddde18a3371c4ca1a86596e8be301
• https://git.kernel.org/stable/c/cffe487026be13eaf37ea28b783d9638ab147204