lib-ssl-iostream: Don't call OPENSSL_cleanup() for openssl 4.0#295
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hector-cao wants to merge 1 commit into
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lib-ssl-iostream: Don't call OPENSSL_cleanup() for openssl 4.0#295hector-cao wants to merge 1 commit into
hector-cao wants to merge 1 commit into
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With OpenSSL 4.0 the lib-dcrypt unit tests (test-crypto, test-stream) segfault at process exit. dovecot_openssl_common_global_ref() installs custom OpenSSL memory functions via CRYPTO_set_mem_functions(); their code lives inside the dynamically loaded OpenSSL/dcrypt module. It also passes OPENSSL_INIT_NO_ATEXIT so that libcrypto does not register its own atexit(OPENSSL_cleanup) handler. dovecot_openssl_common_global_unref() then called OPENSSL_cleanup() explicitly. On OpenSSL 4.0 this explicit cleanup re-arms an internal exit-time cleanup that runs after main() returns [1], i.e. after the module (and therefore the custom memory functions) has been dlclose()d, so libcrypto calls the now-unmapped free() function and the process crashes with SIGSEGV. [1] https://openssl-library.org/post/2026-03-10-remove-atexit/index.html Signed-off-by: Hector Cao <hector.cao@canonical.com>
Contributor
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Thanks, we'll take a look. |
Contributor
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Hi, your explanation sounds bit counter to the blog post you pointed out, which says that atexit handler is not registered ever. |
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With OpenSSL 4.0 the lib-dcrypt unit tests (test-crypto, test-stream) segfault at process exit.
dovecot_openssl_common_global_ref() installs custom OpenSSL memory functions via CRYPTO_set_mem_functions(); their code lives inside the dynamically loaded OpenSSL/dcrypt module. It also passes OPENSSL_INIT_NO_ATEXIT so that libcrypto does not register its own atexit(OPENSSL_cleanup) handler.
dovecot_openssl_common_global_unref() then called OPENSSL_cleanup() explicitly. On OpenSSL 4.0 this explicit cleanup re-arms an internal exit-time cleanup that runs after main() returns [1], i.e. after the module (and therefore the custom memory functions) has been dlclose()d, so libcrypto calls the now-unmapped free() function and the process crashes with SIGSEGV.
[1] https://openssl-library.org/post/2026-03-10-remove-atexit/index.html