Changes for page Homoiconicity

Last modified by Nicolas Gregoire on 2012/01/05 00:18
From version Icon 9.1 Icon
edited by Nicolas Gregoire
on 2012/01/05 00:26
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To version Icon 10.1 Icon
edited by Nicolas Gregoire
on 2012/01/05 00:33
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3 3  Homoiconicity is the property of a programming language that the code and the data are stored in the same format. For example, the following languages are homoiconics :
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5 -* ASM : using bytes stored in memory
6 6  * Lisp : using lists and theirs sub-types
6 +* ASM : using bytes stored in memory
7 7  * XSLT : using the XML format
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9 +In some memory corruption exploits, shellcode is transmitted as data and later executed when the execution flow is altered. This is possible because of homoiconicity. Executing code transmitted as data is sometimes possible with XSLT too.
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9 9  == Triggering embedded code ==
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11 11  In some contexts (like browsers), XSLT code execution can be triggered while a XML document is parsed, via a xsl:stylesheet tag. The executed XSLT code can be stored on the Internet or in the XML document itself (homoiconicity + self-reference trick). A [[blog post>>http://scarybeastsecurity.blogspot.com/2011/01/harmless-svg-xslt-curiousity.html||rel="__blank"]] by Chris Evans describes a pseudo SVG file triggering a simple RAM DoS . But we can do better ;-)