[lkml]   [2017]   [Jun]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH 00/26] Fixing wait, exit, ptrace, exec, and CLONE_THREAD
> Another easy entry point is to see that a multi-threaded setuid won't
> change the credentials on a zombie thread group leader. Which can allow
> sending signals to a process that the credential change should forbid.
> This is in violation of posix and the semantics we attempt to enforce in
> linux.

I might be completely wrong on this point (and I haven't looked at the
patches), but I was under the impression that multi-threaded set[ug]id
was implemented in userspace (by glibc's nptl(7) library that uses RT
signals internally to get each thread to update their credentials). And
given that, I wouldn't be surprised (as a user) that zombie threads will
have stale credentials (glibc isn't running in those threads anymore).

Am I mistaken in that belief?


Aleksa Sarai
Software Engineer (Containers)
SUSE Linux GmbH

 \ /
  Last update: 2017-06-12 00:54    [W:0.206 / U:3.724 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site