Path: csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!news.glorb.com!news-out.readnews.com!news-xxxfer.readnews.com!news.misty.com!news.iecc.com!.POSTED!nerds-end From: Terrence Enger Newsgroups: comp.compilers Subject: Re: Self-modifying code, Function pointers & { Safety, Security} Date: Sat, 15 Mar 2014 09:29:55 -0400 Organization: Compilers Central Lines: 19 Sender: news@iecc.com Approved: comp.compilers@iecc.com Message-ID: <14-03-041@comp.compilers> References: <14-03-015@comp.compilers> <14-03-016@comp.compilers> Reply-To: tenger@iseries-guru.com NNTP-Posting-Host: news.iecc.com Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Trace: miucha.iecc.com 1394893043 22319 2001:470:1f07:1126:0:676f:7373:6970 (15 Mar 2014 14:17:23 GMT) X-Complaints-To: abuse@iecc.com NNTP-Posting-Date: Sat, 15 Mar 2014 14:17:23 +0000 (UTC) Keywords: code, comment Posted-Date: 15 Mar 2014 10:17:22 EDT X-submission-address: compilers@iecc.com X-moderator-address: compilers-request@iecc.com X-FAQ-and-archives: http://compilers.iecc.com Xref: csiph.com comp.compilers:1163 Kaz Kylheku wrote (with blank lines snipped to keep the email-filter happy): > On 2014-03-07, Seima Rao wrote: > > We are used to separation of code from data at the language level. [snip Kaz's response] > > However, two features disupt security : > > i) self-modifying code > > i.e. writing to code space > Note that loading an executable on any operating system constitutes > the above. I believe that the IBM system/i is an exception to that general rule. Only the operating system can write to the code space of a program object. This *does* contribute to the security of the system. [Burroughs mainframes have done that since the 1960s. I wouldn't put too much faith in the security implications though; I once saw a demo of hacking computerized voting machines even though all of the code was in ROM. They constructed a stack with pointers to bits of routines that could be exploited, and then just did a return. -John]