Date: Wed, 30 Jun 2004 07:00:44 -0700 (PDT) From: von thorma <vthorma@yahoo.com> To: naddy@mips.inka.de Cc: freebsd-chat@freebsd.org Subject: Random stack Message-ID: <20040630140044.78387.qmail@web21001.mail.yahoo.com> In-Reply-To: <40E2BF20.9060607@ofdengineering.com>
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> > Is this the right way to go? We're adding more > bloat while openbsd is > > cleaning itself and reworking kernal memory > allocation to make exploits > > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > near impossible. > ^^^^^^^^^^^^^^^ > > Er, what? They have randomized the location in memory where the software will place the stack by adding a randomly sized gap at the top of the stack. Next, they altered the way addresses are stored within the stack and added a way to detect attacks on the stack. They did this by putting buffers closer to the return addresses in the stack, resulting in lower flags and pointers, making them harder for a hacker to hit. The attack detection was accomplished by adding a “canary” that will indicate whether any addresses have been altered. They also broke main memory into two pieces. The first one is devoted to executing code and the second one is isolated as a writable section. The assignment of all pages to one section or another means that no page will be both writable and executable at the same time. > > -- > Christian "naddy" Weisgerber > naddy@mips.inka.de > > _______________________________________________ > freebsd-chat@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-chat > To unsubscribe, send any mail to > "freebsd-chat-unsubscribe@freebsd.org" __________________________________ Do you Yahoo!? New and Improved Yahoo! Mail - Send 10MB messages! http://promotions.yahoo.com/new_mail
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