TSEC: Difference between revisions
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== Notes == | == Notes == | ||
https: | [https://wiki.0x04.net/wiki/Marcin_Ko%C5%9Bcielnicki mwk] shared additional info learned from RE of falcon processors over the years, which hasn't made it into envytools documentation yet: | ||
=== cxset === | === cxset === | ||
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=== Authenticated Mode Entry/Exit === | === Authenticated Mode Entry/Exit === | ||
Entry to Authenticated Mode always sets $pc to the address supplied in $cauth (ie the base of the signature-checked region). This takes effect when trying to branch to any address within the range covered by $cauth. | Entry to Authenticated Mode always sets $pc to the address supplied in $cauth (ie the base of the signature-checked region). This takes effect when trying to branch to any address within the range covered by $cauth. Entry to Authenticated Mode (also called "Secure Mode") computes a MAC over the $cauth region and compares it to $c6 in order to perform the signature check. | ||
Exit from Authenticated Mode must poke a special register (this seems to be I[0x10300] = 0) before leaving authenticated code pages. Failure to do this would result in the Falcon core halting. | Exit from Authenticated Mode must poke a special register (this seems to be I[0x10300] = 0) before leaving authenticated code pages. Failure to do this would result in the Falcon core halting. | ||