Re: Linux 2.6.17.4

From: Chase Venters
Date: Thu Jul 06 2006 - 19:56:27 EST


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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