Re: Linux 2.6.17.4

[Chase Venters <chase.venters@clientec.com>]

On Thursday 06 July 2006 18:48, Willy Tarreau wrote:
> Interestingly, 2.4 tests (arg2 !=0 && arg2 != 1) so from the code changes
> above, it looks like the value 2 was added on purpose, but for what ? Maybe
> the fix is not really correct yet ?

Hence the source of my curiosity. My prctl() manpage says that 2 makes a core 
that is only readable by root.

       PR_SET_DUMPABLE
              (Since  Linux 2.4) Set the state of the flag determining whether
              core dumps are produced for this process upon delivery of a sig-
              nal  whose  default  behaviour is to produce a core dump.  (Nor-
              mally this flag is set for a  process  by  default,  but  it  is
              cleared  when  a set-user-ID or set-group-ID program is executed
              and also by various system calls that  manipulate  process  UIDs
              and  GIDs).  In kernels up to and including 2.6.12, arg2 must be
              either 0 (process is not dumpable) or 1 (process  is  dumpable).
              Since  kernel 2.6.13, the value 2 is also permitted; this causes
              any binary which normally would not be dumped to be dumped read-
              able   by   root   only.    (See   also   the   description   of
              /proc/sys/fs/suid_dumpable in proc(5).)

> Cheers,
> Willy

Thanks,
Chase
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