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On 27 Jan 2012 at 16:25, Kevin Chadwick wrote: |
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> Thanks for the info. In a discussion about malloc flags, it was |
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> mentioned on the OpenBSD list that clearing the memory |
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> immediately brought little in security as it would be cleared before |
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> re-use and if anything could increase the chances of an attacker |
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> writing to areas that he wanted to. |
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the SANITIZE feature of PaX doesn't clear userland memory, it clears kernel pages |
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when they're freed back to the lowest level kernel memory allocator. it is meant |
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to reduce the amount of information that can be leaked by kernel bugs from kernel |
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space to userland. if these pages were cleared on allocation only (as is the case |
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without SANITIZE) then they'd be subject to said infoleaking bugs while sitting |
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on the free page list. |
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also as an optimization these early-cleared pages are not cleared again when the kernel |
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metes them out to the next user. |
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> > Core2Duo |
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> |
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> I don't know the details but according to OpenBSDs Theo, the Core2Duo |
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> had some major design flaws that intel couldn't fix with microcode with |
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> some security implications. |
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yeah, Theo for president! of the lunatic asylum. |
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