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reardencode
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@ariard
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ariard commented Mar 7, 2024

sounds good to me for experimentation.
historically been concerns about raising such limits for the worst-case computationally witness.
some old conversations here: https://bitcoincore.reviews/21224

@petertodd
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In my discussions with miners about Libre Relay, a key thing they've asked for is good unit tests. So any change like this needs to be combined with whatever changes are needed to update the unit tests.

I also second the potential concerns re: DoS attacks. We should be confident that we're not potentially causing problems for miners. That's easy to do with OP_Return, as those scripts can't be executed. Not so easy otherwise.

@ariard
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ariard commented Apr 4, 2024

I also second the potential concerns re: DoS attacks. We should be confident that we're not potentially causing problems for miners. That's easy to do with OP_Return, as those scripts can't be executed. Not so easy otherwise.

@reardencode See the soft / hard limit approach implemented in #6 as a way to minimize DoS surface for raising witness stack element sizes to consensus limit. Current default could stay the soft limit, while it could be opting set by full-node operators to max hard limit.

@petertodd
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I think it'd be more useful to carefully analyze whether or not the stack element sizes pose a DoS attack risk. If they don't, we can just remove the limit.

Of course, IIUC there are no standardness limits for tapscript; that may be sufficient to address the realistic market demand. If no-one wants to create transactions with above-standard stack limits using legacy script, we don't need to change anything.

@ariard
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ariard commented Apr 27, 2024

I think it'd be more useful to carefully analyze whether or not the stack element sizes pose a DoS attack risk

I think stack element sizes poses a DoS attack risk, in a world where you have things like OP_HASH160 / OP_SHA256.
Of course, it’s let computational ressources consumption than an OP_CHECKSIG.

@cryptoquick
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SHA-256 on a megabyte of data is something BitTorrent has done on older computers for a long time

petertodd pushed a commit that referenced this pull request Sep 18, 2024
The previous commit added a test which would fail the
unsigned-integer-overflow sanitizer. The warning is harmless and can be
triggered on any commit, since the code was introduced.

For reference, the warning would happen when the separator `-` was not
present.

For example:

  GET /rest/getutxos/6a297bfa5cb8dd976ab0207a767d6cbfaa5e876f30081127ec8674c8c52b16c0_+1.json

would result in:

rest.cpp:792:77: runtime error: unsigned integer overflow: 18446744073709551615 + 1 cannot be represented in type 'size_type' (aka 'unsigned long')
    #0 0x55ad42c16931 in rest_getutxos(std::any const&, HTTPRequest*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>> const&) src/rest.cpp:792:77
    #1 0x55ad4319e3c0 in std::function<bool (HTTPRequest*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>> const&)>::operator()(HTTPRequest*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>> const&) const /usr/bin/../lib/gcc/x86_64-linux-gnu/13/../../../../include/c++/13/bits/std_function.h:591:9
    #2 0x55ad4319e3c0 in HTTPWorkItem::operator()() src/httpserver.cpp:59:9
    #3 0x55ad431a3eea in WorkQueue<HTTPClosure>::Run() src/httpserver.cpp:114:13
    #4 0x55ad4318f961 in HTTPWorkQueueRun(WorkQueue<HTTPClosure>*, int) src/httpserver.cpp:403:12
    #5 0x7f078ebcbbb3  (/lib/x86_64-linux-gnu/libstdc++.so.6+0xeabb3) (BuildId: 40b9b0d17fdeebfb57331304da2b7f85e1396ef2)
    #6 0x55ad4277e01c in asan_thread_start(void*) asan_interceptors.cpp.o
    #7 0x7f078e840a93  (/lib/x86_64-linux-gnu/libc.so.6+0x9ca93) (BuildId: 08134323d00289185684a4cd177d202f39c2a5f3)
    #8 0x7f078e8cdc3b  (/lib/x86_64-linux-gnu/libc.so.6+0x129c3b) (BuildId: 08134323d00289185684a4cd177d202f39c2a5f3)

SUMMARY: UndefinedBehaviorSanitizer: unsigned-integer-overflow rest.cpp:792:77
petertodd pushed a commit that referenced this pull request Apr 15, 2025
…et_create_transaction

5a26cf7 fuzz: fix `implicit-integer-sign-change` in wallet_create_transaction (brunoerg)

Pull request description:

  This PR limites the value of `m_confirm_target` to avoid `implicit-integer-sign-change`:
  ```
  /ci_container_base/src/wallet/fees.cpp:58:58: runtime error: implicit conversion from type 'unsigned int' of value 4294967292 (32-bit, unsigned) to type 'int' changed the value to -4 (32-bit, signed)
      #0 0x55b6fd26c021 in wallet::GetMinimumFeeRate(wallet::CWallet const&, wallet::CCoinControl const&, FeeCalculation*) ci/scratch/build-x86_64-pc-linux-gnu/src/wallet/./src/wallet/fees.cpp:58:58
      #1 0x55b6fd3ef5ca in wallet::CreateTransactionInternal(wallet::CWallet&, std::vector<wallet::CRecipient, std::allocator<wallet::CRecipient>> const&, std::optional<unsigned int>, wallet::CCoinControl const&, bool) ci/scratch/build-x86_64-pc-linux-gnu/src/wallet/./src/wallet/spend.cpp:1101:49
      #2 0x55b6fd3ebea5 in wallet::CreateTransaction(wallet::CWallet&, std::vector<wallet::CRecipient, std::allocator<wallet::CRecipient>> const&, std::optional<unsigned int>, wallet::CCoinControl const&, bool) ci/scratch/build-x86_64-pc-linux-gnu/src/wallet/./src/wallet/spend.cpp:1382:16
      #3 0x55b6fccbc154 in wallet::(anonymous namespace)::wallet_create_transaction_fuzz_target(std::span<unsigned char const, 18446744073709551615ul>) ci/scratch/build-x86_64-pc-linux-gnu/src/test/fuzz/./src/wallet/test/fuzz/spend.cpp:99:11
      #4 0x55b6fccda45d in std::function<void (std::span<unsigned char const, 18446744073709551615ul>)>::operator()(std::span<unsigned char const, 18446744073709551615ul>) const /usr/bin/../lib/gcc/x86_64-linux-gnu/13/../../../../include/c++/13/bits/std_function.h:591:9
      #5 0x55b6fccda45d in LLVMFuzzerTestOneInput ci/scratch/build-x86_64-pc-linux-gnu/src/test/fuzz/util/./src/test/fuzz/fuzz.cpp:211:5
      #6 0x55b6fc368484 in fuzzer::Fuzzer::ExecuteCallback(unsigned char const*, unsigned long) (/ci_container_base/ci/scratch/build-x86_64-pc-linux-gnu/src/test/fuzz/fuzz+0x1c8a484) (BuildId: d11f8692b05f02b5a14b6e7579598b426e3144c5)
      #7 0x55b6fc367b79 in fuzzer::Fuzzer::RunOne(unsigned char const*, unsigned long, bool, fuzzer::InputInfo*, bool, bool*) (/ci_container_base/ci/scratch/build-x86_64-pc-linux-gnu/src/test/fuzz/fuzz+0x1c89b79) (BuildId: d11f8692b05f02b5a14b6e7579598b426e3144c5)
      #8 0x55b6fc369796 in fuzzer::Fuzzer::ReadAndExecuteSeedCorpora(std::vector<fuzzer::SizedFile, std::allocator<fuzzer::SizedFile>>&) (/ci_container_base/ci/scratch/build-x86_64-pc-linux-gnu/src/test/fuzz/fuzz+0x1c8b796) (BuildId: d11f8692b05f02b5a14b6e7579598b426e3144c5)
      #9 0x55b6fc369ca7 in fuzzer::Fuzzer::Loop(std::vector<fuzzer::SizedFile, std::allocator<fuzzer::SizedFile>>&) (/ci_container_base/ci/scratch/build-x86_64-pc-linux-gnu/src/test/fuzz/fuzz+0x1c8bca7) (BuildId: d11f8692b05f02b5a14b6e7579598b426e3144c5)
      #10 0x55b6fc35719f in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long)) (/ci_container_base/ci/scratch/build-x86_64-pc-linux-gnu/src/test/fuzz/fuzz+0x1c7919f) (BuildId: d11f8692b05f02b5a14b6e7579598b426e3144c5)
      bitcoin#11 0x55b6fc381826 in main (/ci_container_base/ci/scratch/build-x86_64-pc-linux-gnu/src/test/fuzz/fuzz+0x1ca3826) (BuildId: d11f8692b05f02b5a14b6e7579598b426e3144c5)
      bitcoin#12 0x7f934c6661c9  (/lib/x86_64-linux-gnu/libc.so.6+0x2a1c9) (BuildId: 6d64b17fbac799e68da7ebd9985ddf9b5cb375e6)
      bitcoin#13 0x7f934c66628a in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2a28a) (BuildId: 6d64b17fbac799e68da7ebd9985ddf9b5cb375e6)
      bitcoin#14 0x55b6fc34c184 in _start (/ci_container_base/ci/scratch/build-x86_64-pc-linux-gnu/src/test/fuzz/fuzz+0x1c6e184) (BuildId: d11f8692b05f02b5a14b6e7579598b426e3144c5)

  SUMMARY: UndefinedBehaviorSanitizer: implicit-integer-sign-change /ci_container_base/src/wallet/fees.cpp:58:58
  MS: 0 ; base unit: 0000000000000000000000000000000000000000
  0x2e,0x1,0xb0,0xb8,0x0,0xff,0xff,0xff,0xff,0x60,0x14,0x22,0xff,0xff,0xff,0xff,0xff,0xfd,0xff,0xff,0xff,0xff,0xff,0x7e,0xf9,0x41,0x8,0x2b,0x17,0x58,0xb,0x17,0xfc,0xff,0xff,0xff,0xff,0xff,0xff,0x7e,0xf9,0x41,0x8,0x2b,0x17,0x58,0xb,
  .\001\260\270\000\377\377\377\377`\024\"\377\377\377\377\377\375\377\377\377\377\377~\371A\010+\027X\013\027\374\377\377\377\377\377\377~\371A\010+\027X\013
  artifact_prefix='./'; Test unit written to ./crash-5627f57ffba7568a500f8379f62c3338978b43f2
  Base64: LgGwuAD/////YBQi///////9//////9++UEIKxdYCxf8////////fvlBCCsXWAs=
  ```

ACKs for top commit:
  maflcko:
    lgtm ACK 5a26cf7
  dergoegge:
    utACK 5a26cf7

Tree-SHA512: a1b129d81d42350cf85ff6fb95cd6982b6aac88467a526ee4b3c9b3313af2f7952c5dfa9886f455756faba399d8356b6c318d7ab2d6318e08fea838bee90b2fe
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4 participants