Date: Wed, 02 Jan 2019 11:21:27 +0100 From: nisse@...ator.liu.se (Niels Möller) To: oss-security@...ts.openwall.com Subject: Re: Disabling ptrace Jakub Wilk <jwilk@...lk.net> writes: > * Niels Möller <nisse@...ator.liu.se>, 2019-01-01, 12:27: >>Matthew Fernandez <matthew.fernandez@...il.com> writes: >>> E.g. you can attach to the victim process with gdb/ptrace and >>> simply read its memory, if the sysadmin has not blocked this with >>> Yama or similar. >> >> I think one can disable this in the process itself, using prctl with >> PR_SET_DUMPABLE. But documentation is a bit unclear and doesn't >> exlicitly mention effect on ptrace > > The prctl(2) man page reads: “Processes that are not dumpable can not > be attached via ptrace(2) PTRACE_ATTACH; see ptrace(2) for further > details.” Thanks, I somehow missed that. So prctl should be the right tool, then. >>(and other debugging interfaces). > > What other interfaces do you have in mind? I had the impression that ptrace was old-fashined, and that current gdb used other interfaces via /proc (with permissions also affected by prctl). But I may be mistaken; I've never looked into those details. Regards, /Niels -- Niels Möller. PGP-encrypted email is preferred. Keyid 368C6677. Internet email is subject to wholesale government surveillance.
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