Messages in this thread | | | Date | Tue, 16 Nov 2021 14:02:32 +0100 | Subject | Re: [PATCH 0/8] memset() in crypto code | From | Christophe Leroy <> |
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Le 16/11/2021 à 12:20, Sandy Harris a écrit : > Fairly often we want to clear some memory in crypto code; it holds > things we are done using and do not want to leave lying around where > an enemy might discover them. Typical examples are crypto keys or > random numbers we have generated and used for output. > > The obvious way to do this is with memset(address,0,bytes) but there > is a problem with that; because we are done using that memory, the > compiler may optimise away the "useless" memset() call. Using > memzero_explicit(address,bytes) instead solves the problem; that > function is designed to resist the optimisation. > > There are well over 100 memset() calls in .c files in the crypto and > security directories. I looked at them all and found about a dozen in > eight files that I thought should be changed to memzero_explicit(). > Here they are as patches 1 to 8 in this series. > > I did read some code & think moderately carefully, but I do not know > the code deeply & it is possible I have made some errors. I think > false positives (making unnecessary changes) are more likely than > false negatives (not catching necessary changes). >
I see no point in doing 8 separate patches that all have the same subject and the exact same light description.
I think it would be better to have a single patch with all the changes, and use the cover letter description as description for that patch.
Christophe
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