osslsigncode tool with kmsp module crashes, segmentation fault

[git-lul]

We are using osslsigncode tool to code sign executables with pkcs11 engine from OpenSC and libkmsp11 module. Example of command line:

./osslsigncode sign -pkcs11engine pkcs11.so -pkcs11module libkmsp11.so -certs cert.pem -key pkcs11:object=KEY-ID -h sha256 -addUnauthenticatedBlob -in file -out tmp

This fails with signal: segmentation fault (core dumped) and following is stack trace obtained by gdb from core dump:

#0  0x000079575a232d80 in bssl::CERT::~CERT() () from libkmsp11.so
#1  0x000079575a21f59a in bssl::SSL_CONFIG::~SSL_CONFIG() () from libkmsp11.so
#2  0x000079575a21ed16 in ssl_st::~ssl_st() () from libkmsp11.so
#3  0x000079575a21f6e3 in SSL_free () from libkmsp11.so
#4  0x000079575a21c1c5 in ssl_protector_destroy(tsi_frame_protector*) () from libkmsp11.so
#5  0x000079575a458b69 in secure_endpoint_unref((anonymous namespace)::secure_endpoint*) () from libkmsp11.so
#6  0x000079575a15da6c in grpc_chttp2_transport::~grpc_chttp2_transport() () from libkmsp11.so
#7  0x000079575a16f982 in grpc_core::(anonymous namespace)::InitTransportClosure<&(read_action_locked(grpc_core::RefCountedPtr<grpc_chttp2_transport>, absl::Status))>(grpc_core::RefCountedPtr<grpc_chttp2_transport>, grpc_closure*)::{lambda(void*, absl::Status)#1}::__invoke(void*, absl::Status) ()
   from libkmsp11.so
#8  0x000079575a5373e3 in grpc_combiner_continue_exec_ctx() () from libkmsp11.so
#9  0x000079575a537fee in grpc_core::ExecCtx::Flush() () from libkmsp11.so
#10 0x000079575a537ec9 in void absl::internal_any_invocable::LocalInvoker<false, void, queue_offload(grpc_core::Combiner*)::$_0&>(absl::internal_any_invocable::TypeErasedState*) () from libkmsp11.so
#11 0x000079575a51d600 in grpc_event_engine::experimental::SelfDeletingClosure::Run() () from libkmsp11.so
#12 0x000079575a51d09d in grpc_event_engine::experimental::WorkStealingThreadPool::ThreadState::Step() () from libkmsp11.so
#13 0x000079575a51cee8 in grpc_event_engine::experimental::WorkStealingThreadPool::ThreadState::ThreadBody() () from libkmsp11.so
#14 0x000079575a51d62f in grpc_event_engine::experimental::WorkStealingThreadPool::WorkStealingThreadPoolImpl::StartThread()::$_0::__invoke(void*) () from libkmsp11.so
#15 0x000079575a54a2fc in grpc_core::(anonymous namespace)::ThreadInternalsPosix::ThreadInternalsPosix(char const*, void (*)(void*), void*, bool*, grpc_core::Thread::Options const&)::{lambda(void*)#1}::__invoke(void*) () from libkmsp11.so
#16 0x000079575ac9caa4 in ?? () from core.2718761.packed/lib/x86_64-linux-gnu/libc.so.6
#17 0x000079575ad29c3c in ?? () from core.2718761.packed/lib/x86_64-linux-gnu/libc.so.6

I do not have exact steps for reproduction, it occurs randomly and not very often, something like once in 1000 invocations of the tool.

Happens on: Ubuntu 24.04.2 LTS
Versions of the tool and libs are following:

• osslsigncode: 2.8
• libpcks11: 0.4.16
• libkmsp11: 1.8

[tdbhacks]

We have seen similar sort of errors in the past, though sadly have never been able to debug/fix successfully. I'll keep this open for now, but these kinds of race conditions / threading issues are tricky to address, because it's also unclear how much the library is responsible for them vs. external dependencies such as gRPC (mentioned in the stack and culprit of other issues in the past).

Apologies for the not-so-helpful reply