Description: vfs: fs_context: fix up param length parsing in legacy_parse_param
References:
 https://www.openwall.com/lists/oss-security/2022/01/18/7
Notes:
 carnil> Introduced with 3e1aeb00e6d1 ("vfs: Implement a filesystem
 carnil> superblock creation/configuration context") in 5.1-rc1.
Bugs:
upstream: pending [722d94847de29310e8aa03fcbdb41fc92c521756]
5.10-upstream-stable: needed
4.19-upstream-stable: N/A "Vulnerable code not present"
4.9-upstream-stable: N/A "Vulnerable code not present"
sid: released (5.15.15-1) [bugfix/all/vfs-fs_context-fix-up-param-length-parsing-in-legacy.patch]
5.10-bullseye-security: pending (5.10.92-1) [bugfix/all/vfs-fs_context-fix-up-param-length-parsing-in-legacy.patch]
4.19-buster-security: N/A "Vulnerable code not present"
4.9-stretch-security: N/A "Vulnerable code not present"