[tor-bugs] #29140 [Core Tor/Tor]: Tor privdrop on (Open)BSD fails to reclaim capabilities of "User".

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#29140: Tor privdrop on (Open)BSD fails to reclaim capabilities of "User".
-------------------------------------------------+-------------------------
 Reporter:  RatherAnonymousOne                   |          Owner:  (none)
     Type:  defect                               |         Status:  new
 Priority:  Medium                               |      Component:  Core
                                                 |  Tor/Tor
  Version:  Tor: 0.3.4.9                         |       Severity:  Normal
 Keywords:  openbsd, bsd, privilege drop, user,  |  Actual Points:
  torrc, root, disableallswap, capabilities      |
Parent ID:                                       |         Points:
 Reviewer:                                       |        Sponsor:
-------------------------------------------------+-------------------------
 As summary states. Should Tor need invocation as superuser it will fail
 claim the capabilities of the target "User" in torrc. One statement that
 is therefore affected is e.g. "DisableAllSwap 1" which would either
 require Tor running as root or raising of superuser capabilities (this was
 never tested however). Both alternatives are unattractive.

 Regarding option with "DisableAllSwap" I will give pretty obvious pointers
 from your own GitHub repositories:

 L1510 @ src/app/config/config.c
 L220  @ src/lib/process/setuid.c
 L316  @ src/lib/process/setuid.c

 And here is kdump format of a ktrace of faulty execution:
 {{{
 28446 tor      CALL  setegid(1000<"user">)
 28446 tor      RET   setegid 0
 28446 tor      CALL  setgid(1000<"user">)
 28446 tor      RET   setgid 0
 28446 tor      CALL  setuid(1000<"user">)
 28446 tor      RET   setuid 0
 28446 tor      CALL  seteuid(1000<"user">)
 28446 tor      RET   seteuid 0
 28446 tor      CALL  setgid(0<"wheel">)
 28446 tor      RET   setgid -1 errno 1 Operation not permitted
 28446 tor      CALL  setegid(0<"wheel">)
 28446 tor      RET   setegid -1 errno 1 Operation not permitted
 28446 tor      CALL  setuid(0<"root">)
 28446 tor      RET   setuid -1 errno 1 Operation not permitted
 28446 tor      CALL  seteuid(0<"root">)
 28446 tor      RET   seteuid -1 errno 1 Operation not permitted
 }}}

 P.S. This applies to 0.3.4.9 but also to 0.3.5.7.

 P.P.S. I am sorry I did not take the time to patch this myself yes. For
 anyone interested in this these are great resources:

 man 2 setuid
 man 2 seteuid
 man 2 setgid
 man 2 setegid
 man 2 getrlimit
 man 2 setrlimit

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/29140>
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