ubsan: add another suppression for InsecureRandomContext

fanquake commented at 1:52 pm on November 26, 2025: member

We’ve been suppressing this in infra for a little while, it’s now appearing elsewhere. i.e https://github.com/willcl-ark/bitcoin/actions/runs/19702968577/job/56443491265#step:9:2738:

 0Run bip324_cipher_roundtrip with args ['/home/runner/work/_temp/build/bin/fuzz', '-runs=1', PosixPath('/home/runner/work/_temp/ci/scratch/qa-assets/fuzz_corpora/bip324_cipher_roundtrip')]INFO: Running with entropic power schedule (0xFF, 100).
 1INFO: Seed: 2138761624
 2INFO: Loaded 1 modules   (612416 inline 8-bit counters): 612416 [0x55aa0745d458, 0x55aa074f2c98), 
 3INFO: Loaded 1 PC tables (612416 PCs): 612416 [0x55aa074f2c98,0x55aa07e4b098), 
 4INFO:     1479 files found in /home/runner/work/_temp/ci/scratch/qa-assets/fuzz_corpora/bip324_cipher_roundtrip
 5INFO: -max_len is not provided; libFuzzer will not generate inputs larger than 214082 bytes
 6INFO: seed corpus: files: 1479 min: 1b max: 214082b total: 869543b rss: 112Mb
 7/home/runner/work/_temp/src/random.h:432:29: runtime error: unsigned integer overflow: 11400714825904921328 * 13787848793156543929 cannot be represented in type 'unsigned long'
 8    [#0](/bitcoin-bitcoin/0/) 0x55aa041751db in InsecureRandomContext::InsecureRandomContext(unsigned long) (/home/runner/work/_temp/build/bin/fuzz+0x1c181db) (BuildId: 240d4d47bf0144daf13a950328fb39f74c0478d6)
 9    [#1](/bitcoin-bitcoin/1/) 0x55aa041737c4 in bip324_cipher_roundtrip_fuzz_target(std::span<unsigned char const, 18446744073709551615ul>) (/home/runner/work/_temp/build/bin/fuzz+0x1c167c4) (BuildId: 240d4d47bf0144daf13a950328fb39f74c0478d6)
10    [#2](/bitcoin-bitcoin/2/) 0x55aa04a13ea5 in LLVMFuzzerTestOneInput (/home/runner/work/_temp/build/bin/fuzz+0x24b6ea5) (BuildId: 240d4d47bf0144daf13a950328fb39f74c0478d6)
11    [#3](/bitcoin-bitcoin/3/) 0x55aa040189ff in fuzzer::Fuzzer::ExecuteCallback(unsigned char const*, unsigned long) (/home/runner/work/_temp/build/bin/fuzz+0x1abb9ff) (BuildId: 240d4d47bf0144daf13a950328fb39f74c0478d6)
12    [#4](/bitcoin-bitcoin/4/) 0x55aa04018009 in fuzzer::Fuzzer::RunOne(unsigned char const*, unsigned long, bool, fuzzer::InputInfo*, bool, bool*) (/home/runner/work/_temp/build/bin/fuzz+0x1abb009) (BuildId: 240d4d47bf0144daf13a950328fb39f74c0478d6)
13    [#5](/bitcoin-bitcoin/5/) 0x55aa04019d72 in fuzzer::Fuzzer::ReadAndExecuteSeedCorpora(std::vector<fuzzer::SizedFile, std::allocator<fuzzer::SizedFile>>&) (/home/runner/work/_temp/build/bin/fuzz+0x1abcd72) (BuildId: 240d4d47bf0144daf13a950328fb39f74c0478d6)
14    [#6](/bitcoin-bitcoin/6/) 0x55aa0401a290 in fuzzer::Fuzzer::Loop(std::vector<fuzzer::SizedFile, std::allocator<fuzzer::SizedFile>>&) (/home/runner/work/_temp/build/bin/fuzz+0x1abd290) (BuildId: 240d4d47bf0144daf13a950328fb39f74c0478d6)
15    [#7](/bitcoin-bitcoin/7/) 0x55aa04006915 in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long)) (/home/runner/work/_temp/build/bin/fuzz+0x1aa9915) (BuildId: 240d4d47bf0144daf13a950328fb39f74c0478d6)
16    [#8](/bitcoin-bitcoin/8/) 0x55aa04032cd6 in main (/home/runner/work/_temp/build/bin/fuzz+0x1ad5cd6) (BuildId: 240d4d47bf0144daf13a950328fb39f74c0478d6)
17    [#9](/bitcoin-bitcoin/9/) 0x7f8d6de271c9  (/lib/x86_64-linux-gnu/libc.so.6+0x2a1c9) (BuildId: 274eec488d230825a136fa9c4d85370fed7a0a5e)
18    [#10](/bitcoin-bitcoin/10/) 0x7f8d6de2728a in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2a28a) (BuildId: 274eec488d230825a136fa9c4d85370fed7a0a5e)
19    [#11](/bitcoin-bitcoin/11/) 0x55aa03ffaee4 in _start (/home/runner/work/_temp/build/bin/fuzz+0x1a9dee4) (BuildId: 240d4d47bf0144daf13a950328fb39f74c0478d6)
20
21SUMMARY: UndefinedBehaviorSanitizer: unsigned-integer-overflow /home/runner/work/_temp/src/random.h:432:29

We've been suppressing this in infra for a little while, it's now
appearing elsewhere. i.e
https://github.com/willcl-ark/bitcoin/actions/runs/19702968577/job/56443491265#step:9:2738.

d35b1755e0

DrahtBot commented at 1:52 pm on November 26, 2025: contributor

The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

Code Coverage & Benchmarks

For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/33949.

Reviews

See the guideline for information on the review process.

Type	Reviewers
ACK	dergoegge

If your review is incorrectly listed, please copy-paste <!–meta-tag:bot-skip–> into the comment that the bot should ignore.

fanquake commented at 1:52 pm on November 26, 2025: member

cc @willcl-ark @dergoegge

maflcko commented at 2:41 pm on November 26, 2025: member

Not sure. Is this caused by removing -g? If yes, I am not sure this is something meaningful to support when running with sanitizers.

maflcko commented at 2:43 pm on November 26, 2025: member

Going further, we could require -fno-inline for ubsan. But if you want to go the route in this pull, might as well just wildcard-suppress InsecureRandomContext?

dergoegge approved

dergoegge commented at 2:58 pm on November 26, 2025: member

ACK d35b1755e0fe7f4760ea76dd2ba054e568bb8395

Don’t feel strongly about adding this, also happy to just keep adding this to my own suppressions.

maflcko commented at 6:15 pm on November 27, 2025: member

To explain my comment: On this pull and current master the compile flags are: C++ compiler flags .................... -ftrivial-auto-var-init=pattern -O2 -g -std=c++20 ...

On the failing push, they are: C++ compiler flags .................... -ftrivial-auto-var-init=pattern -O2 -std=c++20 ... (with -g removed)

So I fail to see why the correct fix is to add a suppression. See also the docs:

https://clang.llvm.org/docs/UndefinedBehaviorSanitizer.html#runtime-suppressions

Sometimes your binary must have enough debug info and/or symbol table, so that the runtime could figure out source file or function name to match against the suppression.

fanquake commented at 10:13 am on November 28, 2025: member

I think this is the same issue in our infra.

fanquake closed this on Nov 28, 2025

fanquake deleted the branch on Nov 28, 2025

ubsan: add another suppression for InsecureRandomContext #33949

Code Coverage & Benchmarks

Reviews