Hi Igor, On 8/13/21 10:05 AM, Igor Zhbanov wrote: > Hi Simon, > >> Yes, what I meant was that maybe you could just declare it at the beginning of the function, >> and not use it at all in the sysctl table. Because as I see it, you only use allowed_caps_hex in the sysctl >> table to copy the string to that temporary (variable), and its use is limited to that one function. >> >> Instead of: >> >> + if ((error = proc_dostring(table, write, buffer, lenp, ppos))) >> + return error; > ... >> You could probably get away with something like: > ... >> + strncpy(allowed_caps_hex, buffer, ALLOWED_CAPS_HEX_LEN + 1); > > proc_dostring() is more than simple strncpy(). It is handling offsets too. > I.e. if a user will try to write not from the starting position. But > I've seen that some > functions simply create an instance of struct ctl_table, fill it and > call needed function. Oh you're right, I assumed the sysctls write always had to be written from position zero, but I just learned of 'sysctl_writes_strict': even though by default the kernel forbid writes at another offset than zero or partial writes on sysctl files, users can enable a more permissive behavior like 'SYSCTL_WRITES_LEGACY'. Sorry about that. > > Thanks. > Thanks, Simon
