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SubjectRe: [PATCH 2/4] selftests/sgx: Fix Q1 and Q2 calculation in sigstruct.c
On 7/5/21 7:36 AM, Jarkko Sakkinen wrote:
> From: Tianjia Zhang <>
> Q1 and Q2 are numbers with *maximum* length of 384 bytes. If the calculated
> length of Q1 and Q2 is less than 384 bytes, things will go wrong.
> E.g. if Q2 is 383 bytes, then
> 1. The bytes of q2 are copied to sigstruct->q2 in calc_q1q2().
> 2. The entire sigstruct->q2 is reversed, which results it being
> 256 * Q2, given that the last byte of sigstruct->q2 is added
> to before the bytes given by calc_q1q2().
> Either change in key or measurement can trigger the bug. E.g. an unmeasured
> heap could cause a devastating change in Q1 or Q2.
> Reverse exactly the bytes of Q1 and Q2 in calc_q1q2() before returning to
> the caller.
> Fixes: 2adcba79e69d ("selftests/x86: Add a selftest for SGX")
> Link:
> Signed-off-by: Tianjia Zhang <>
> Signed-off-by: Jarkko Sakkinen <>

This looks fine, but can I suggest a Subject: tweak?

selftests/sgx: Fix calculations for sub-maximum field sizes

In any case:

Reviewed-by: Dave Hansen <>

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