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hardening: add MP_ZERO_BUFFER, MP_ZERO_DIGITS #255

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merged 1 commit into from
May 12, 2019
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hardening: add MP_ZERO_BUFFER, MP_ZERO_DIGITS #255

merged 1 commit into from
May 12, 2019

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minad
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@minad minad commented May 11, 2019 •
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  • (!) Always zero buffer before freeing if MP_NO_ZERO_ON_FREE is not defined
  • Add MP_NO_ZERO_ON_FREE to disable hardening
  • Add MP_ZERO_BUFFER, MP_ZERO_DIGITS, MP_FREE_BUFFFER, MP_FREE_DIGITS
  • Never use MP_FREE directly, use MP_FREE_DIGITS or MP_FREE_BUFFER
  • Add MP_USE_MEMSET to use memset instead of loop
  • Disable astyle backups which are annonying in the times of git

@minad minad force-pushed the hardening branch 3 times, most recently from bc8d46d to 95513f1 Compare May 11, 2019 09:48
@minad minad requested review from czurnieden and sjaeckel May 11, 2019 10:01
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czurnieden reviewed May 11, 2019
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czurnieden approved these changes May 11, 2019
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As long as it can be switched off when not needed: yepp, good idea.

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hardening: add MP_ZERO_BUFFER, MP_ZERO_DIGITS
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* (!) Always zero buffer before freeing if MP_NO_ZERO_ON_FREE is not defined
* Add MP_NO_ZERO_ON_FREE to disable hardening
* Add MP_ZERO_BUFFER, MP_ZERO_DIGITS, MP_FREE_BUFFFER, MP_FREE_DIGITS
* Never use MP_FREE directly, use MP_FREE_DIGITS or MP_FREE_BUFFER
* Add MP_USE_MEMSET to use memset instead of loop
* Disable astyle backups which are annonying in the times of git
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minad commented May 11, 2019 •
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rebased and missing casts added

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minad commented May 12, 2019

@sjaeckel This one should be ready.

@sjaeckel sjaeckel merged commit 235e831 into develop May 12, 2019
@sjaeckel sjaeckel deleted the hardening branch May 12, 2019 09:52
@minad minad mentioned this pull request May 13, 2019
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minad commented May 17, 2019

See https://www.usenix.org/system/files/conference/usenixsecurity17/sec17-yang.pdf for issues regarding memset deadstore elim. There is explicit_bzero for example in OpenBSD. Maybe more relevant for LTC.

@minad minad mentioned this pull request May 23, 2019
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@sjaeckel sjaeckel sjaeckel approved these changes

@czurnieden czurnieden czurnieden approved these changes

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