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SLAM: a new Spectre technique
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SLAM: a new Spectre technique

tentortentor Member, Host Rep

Many processor vendors provide a mechanism to allow some bits of a pointer value to be used to store unrelated data; these include Intel's linear address masking (LAM), AMD's upper address ignore, and Arm's top-byte ignore. A set of researchers has now come up with a way (that they call "SLAM") to use those features to bypass many checks on pointer validity, opening up a new set of Spectre attacks.

In response to SLAM, Intel made plans to provide software guidance prior to the future release of Intel processors which support LAM (e.g., deploying LAM jointly with LASS). Linux engineers developed patches to disable LAM by default until further guidance is available. ARM published an advisory to provide guidance on future TBI-enabled CPUs. AMD did not implement guidance updates and pointed to existing Spectre v2 mitigations to address the SLAM exploit described in the paper.

Thanked by 1chitree

Comments

  • raindog308raindog308 Administrator, Veteran

    @tentor said: these include Intel's linear address masking (LAM),

    From the link:

    "The consequences of confusing user-space and kernel-space addresses could be severe and contribute to the ongoing CVE-number shortage"

    LOL

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