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[bp/1.35] compat/openssl: Ensure OpenSSL uses tcmalloc functions #596

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Merged
jwendell merged 1 commit into from
Aug 18, 2026
Merged

[bp/1.35] compat/openssl: Ensure OpenSSL uses tcmalloc functions #596

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44 changes: 39 additions & 5 deletions bssl-compat/prefixer/prefixer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -491,6 +491,24 @@ void MyFrontendAction::EndSourceFileAction() {
<< "static void " << opt::prefix << "_init(void) __attribute__ ((constructor));" << std::endl
<< "static void " << opt::prefix << "_fini(void) __attribute__ ((destructor));" << std::endl
<< std::endl
<< "static void *ossl_malloc(size_t num, const char *file, int line) {" << std::endl
<< " (void)file;" << std::endl
<< " (void)line;" << std::endl
<< " return malloc(num);" << std::endl
<< "}" << std::endl
<< std::endl
<< "static void *ossl_realloc(void *addr, size_t num, const char *file, int line) {" << std::endl
<< " (void)file;" << std::endl
<< " (void)line;" << std::endl
<< " return realloc(addr, num);" << std::endl
<< "}" << std::endl
<< std::endl
<< "static void ossl_free(void *addr, const char *file, int line) {" << std::endl
<< " (void)file;" << std::endl
<< " (void)line;" << std::endl
<< " free(addr);" << std::endl
<< "}" << std::endl
<< std::endl
<< "static void *lookup(const char *symbol) {" << std::endl
<< " void *result;" << std::endl
<< " const char *s = symbol + " << opt::prefix.size() + 1 << ";" << std::endl
Expand All @@ -510,11 +528,6 @@ void MyFrontendAction::EndSourceFileAction() {
<< " exit(ELIBACC);" << std::endl
<< " }" << std::endl
<< std::endl
<< " if((libssl = ossl_dlopen(LIBSSL_SO)) == NULL) {" << std::endl
<< " fprintf(stderr, \"%s: dlopen(%s) : %s\\n\", __func__, LIBSSL_SO, dlerror());" << std::endl
<< " exit(ELIBACC);" << std::endl
<< " }" << std::endl
<< std::endl
<< " ossl.ossl_OpenSSL_version_num = (ossl_OpenSSL_version_num_t)lookup(\"ossl_OpenSSL_version_num\");" << std::endl
<< " if (ossl.ossl_OpenSSL_version_num == NULL) {" << std::endl
<< " fprintf(stderr, \"%s: Failed to load OpenSSL_version_num()\\n\", __func__);" << std::endl
Expand All @@ -533,6 +546,27 @@ void MyFrontendAction::EndSourceFileAction() {
<< " major, minor, patch);" << std::endl
<< " exit(ELIBACC);" << std::endl
<< " }" << std::endl
<< std::endl
<< " typedef int (*CRYPTO_set_mem_functions_fn)(" << std::endl
<< " void *(*malloc_fn)(size_t, const char *, int)," << std::endl
<< " void *(*realloc_fn)(void *, size_t, const char *, int)," << std::endl
<< " void (*free_fn)(void *, const char *, int));" << std::endl
<< std::endl
<< " CRYPTO_set_mem_functions_fn set_mem_fn = lookup(\"CRYPTO_set_mem_functions\");" << std::endl
<< " if (set_mem_fn == NULL) {" << std::endl
<< " fprintf(stderr, \"%s: dlsym(libcrypto, \\\"CRYPTO_set_mem_functions\\\") : %s\\n\", __func__, dlerror());" << std::endl
<< " exit(ELIBACC);" << std::endl
<< " }" << std::endl
<< std::endl
<< " if (!set_mem_fn(ossl_malloc, ossl_realloc, ossl_free)) {" << std::endl
<< " fprintf(stderr, \"%s: CRYPTO_set_mem_functions() failed\\n\", __func__);" << std::endl
<< " exit(ELIBACC);" << std::endl
<< " }" << std::endl
<< std::endl
<< " if((libssl = ossl_dlopen(LIBSSL_SO)) == NULL) {" << std::endl
<< " fprintf(stderr, \"%s: dlopen(%s) : %s\\n\", __func__, LIBSSL_SO, dlerror());" << std::endl
<< " exit(ELIBACC);" << std::endl
<< " }" << std::endl
<< std::endl;

for(const auto &function : m_functions) {
Expand Down
20 changes: 20 additions & 0 deletions bssl-compat/source/test/test_crypto.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -5,3 +5,23 @@ TEST(TestCrypto, test_FIPS_mode) {
ASSERT_EQ(0, FIPS_mode());
}

#ifdef BSSL_COMPAT
#include <dlfcn.h>

TEST(TestCrypto, test_openssl_uses_main_executable_allocator) {
ossl_CRYPTO_malloc_fn malloc_fn = nullptr;
ossl_CRYPTO_realloc_fn realloc_fn = nullptr;
ossl_CRYPTO_free_fn free_fn = nullptr;
ossl_CRYPTO_get_mem_functions(&malloc_fn, &realloc_fn, &free_fn);

Dl_info info;
ASSERT_NE(dladdr(reinterpret_cast<void *>(malloc_fn), &info), 0);
EXPECT_EQ(std::string(info.dli_fname).find("libcrypto"), std::string::npos);

ASSERT_NE(dladdr(reinterpret_cast<void *>(realloc_fn), &info), 0);
EXPECT_EQ(std::string(info.dli_fname).find("libcrypto"), std::string::npos);

ASSERT_NE(dladdr(reinterpret_cast<void *>(free_fn), &info), 0);
EXPECT_EQ(std::string(info.dli_fname).find("libcrypto"), std::string::npos);
}
#endif
4 changes: 4 additions & 0 deletions changelogs/current/bug_fixes/tls__ensure-openssl-uses-tcmalloc.rst
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Original file line number Diff line number Diff line change
@@ -0,0 +1,4 @@
Fixed a bug where OpenSSL was using glibc's allocator instead of tcmalloc. This
resulted in OpenSSL operating on a completely separate heap, defeating
tcmalloc's performance benefits on the TLS hot path and making all OpenSSL
allocations invisible to tcmalloc heap profiling and memory dumps.
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