NFSD: Prevent a potential integer overflow

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: NFSD: Prevent a potential integer overflow If the tag length is >= U32_MAX - 3 then the "length + 4" addition can result in an integer overflow. Address this by splitting the decoding into several steps so that decode_cb_compound4res() does not have to perform arithmetic on the unsafe length value.

References

• https://git.kernel.org/stable/c/745f7ce5a95e783ba62fe774325829466aec2aa8
• https://git.kernel.org/stable/c/90adbae9dd158da8331d9fdd32077bd1af04f553
• https://git.kernel.org/stable/c/3c5f545c9a1f8a1869246f6f3ae8c17289d6a841
• https://git.kernel.org/stable/c/842f1c27a1aef5367e535f9e85c8c3b06352151a
• https://git.kernel.org/stable/c/de53c5305184ca1333b87e695d329d1502d694ce
• https://git.kernel.org/stable/c/dde654cad08fdaac370febb161ec41eb58e9d2a2
• https://git.kernel.org/stable/c/084f797dbc7e52209a4ab6dbc7f0109268754eb9
• https://git.kernel.org/stable/c/ccd3394f9a7200d6b088553bf38e688620cd27af
• https://git.kernel.org/stable/c/7f33b92e5b18e904a481e6e208486da43e4dc841