Doing so could be considered UB in a pedantic interpretation of the standard. Avoid it.
Closes #876.
Avoid passing out-of-bound pointers to 0-size memcpy #879
pull sipa wants to merge 1 commits into bitcoin-core:master from sipa:202101_no_zero_memcpy changing 3 files +4 −4-
sipa commented at 5:57 AM on January 24, 2021: contributor
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9570f674cc
Avoid passing out-of-bound pointers to 0-size memcpy
Doing so could be considered UB in a strict reading of the standard. Avoid it.
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practicalswift commented at 7:50 AM on January 24, 2021: contributor
cr ACK 9570f674cc729cafcba65f4cce03552d9a6108f4: patch looks correct
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real-or-random commented at 5:53 PM on January 24, 2021: contributor
When we change the contrib functions, we should also consider changing the copies in Bitcoin Core, see #781 edit: What I'm saying is: Let's take care of this in #781.
Can you also change the comparison in the same function here https://github.com/bitcoin-core/secp256k1/blob/9570f674cc729cafcba65f4cce03552d9a6108f4/src/ecdsa_impl.h#L115
to read
rlen > (size_t)(sigend - *sig)? This will never compute an out-of-bounds pointer (which is another case of pedantic UB). -
real-or-random commented at 6:46 AM on June 11, 2021: contributor
@sipa ping
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real-or-random commented at 8:19 AM on June 16, 2021: contributor
ACK 9570f674cc729cafcba65f4cce03552d9a6108f4
I'll open a new PR for the other issue
- real-or-random merged this on Jun 16, 2021
- real-or-random closed this on Jun 16, 2021
- real-or-random referenced this in commit 920a0e5fa6 on Oct 17, 2021
- Fabcien referenced this in commit 7380db86f5 on Jan 9, 2026
- Fabcien referenced this in commit d53ad18aed on Jan 9, 2026
