Am Montag, 5. April 2004 10:27 schrieb Peter Waechtler:
> With the current behavior typical server programs that switch euid
> don't dump core. This is done "for security".
> If the core file pattern exists the dump is written to but readable
> for the file owner (not necessarily root - don't argue: only chdir into
> dirs that only root can write to: think of file servers like samba)
>
> The patch below addresses this (but still not perfect).
> What I would like to see: instead of mm->dumpable=0 when calling seteuid()
> something like mm->dumpAs=root and making sure that the core is owned by
> root mode 600
>
> I could install a sighandler that calls prctl(PR_SET_DUMPABLE,1,0,0,0),
> switch euid to root, but still the formerly placed core is owned by evil
> user :(
> Then I could read the core pattern and unlink such a file - and all this
> just for the Linux platform...
>

Unlink a previously existing core.
I tried on solaris - I find the behavior (tunable with coreadm) perfect:
Switched uid? -> create as root (unlink a previously and potentially opened
core first: yes it got a new inode) then creat(O_EXCL,0600)