Re: /proc/<pid>/mem unreadable (was strace and linux 1.3.97)

Matthias Urlichs (smurf@smurf.noris.de)
Fri, 3 May 1996 10:11:41 +0100

In linux.dev.kernel, article <199605021038.FAA16498@caffeine.io.com>,
"James H. Cloos Jr." <cloos@jhcloos.com> writes:
>=20
> Seems to me that the answer, then, is to have /prov/<pid>/mem mod 600
> and owned by the euid of the process, rather than owned by the uid
> that ran it. Linus?
>=20
No, that woon't work, for when the setuid program does a
seteuid(getuid())
exec(user_program)

it's still vulnerable between these two calls.

The _only_ workable solution for this is to invalidate the /proc/###/me=
m
inode when the process in question calls exec().

--=20
Mathematicians do it symmetrically.
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