> it is a complex piece of software where logic errors can create serious security issues.
I know many unix commands have a lot of capabilities I never use, sudo? Not much logic other than "run this as root if user has permission" is there? OTOH I never thought about how a cli app can escalate privilige without already having it....
The escalating privileges part is easy: the file /usr/bin/sudo is owned by root and has the setuid flag set, meaning it gets executed with the permissions of the file owner instead of those of the caller.
The complexity has more to do with the fact that it has 28 command line flags, plus a fairly complex config file to configure who is allowed to do what, impersonating which user, and whether they need a password to do so. All of that dealing with security critical stuff like what exactly should carry over and what should be reset (all configurable ofc).
su is very simple by comparison (and you can do `sudo -s` anyways to get the same result as calling su without parameters).
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I know many unix commands have a lot of capabilities I never use, sudo? Not much logic other than "run this as root if user has permission" is there? OTOH I never thought about how a cli app can escalate privilige without already having it....
The escalating privileges part is easy: the file /usr/bin/sudo is owned by root and has the setuid flag set, meaning it gets executed with the permissions of the file owner instead of those of the caller.
The complexity has more to do with the fact that it has 28 command line flags, plus a fairly complex config file to configure who is allowed to do what, impersonating which user, and whether they need a password to do so. All of that dealing with security critical stuff like what exactly should carry over and what should be reset (all configurable ofc).
su is very simple by comparison (and you can do `sudo -s` anyways to get the same result as calling su without parameters).