Segmentation fault when trying to use secure-transport with curl 8.12.0 multissl

[thisisgk]

I did this

Configured and built curl with:

$ ./configure \
--with-secure-transport \
--with-openssl \
--with-default-ssl-backend=openssl
$ make

Ran curl and got:

$ CURL_SSL_BACKEND=secure-transport ./src/curl -q -s -v https://example.com/ >/dev/null
Segmentation fault: 11

Then I rebuilt curl with ./configure --enable-debug ..., the crash log shows:

Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0   ???                             000000000000000000 0 + 0
1   libcurl.4.dylib                 0x0000000104f8bd00 multissl_init + 48 (vtls.c:918)
2   libcurl.4.dylib                 0x0000000104f87474 Curl_ssl_init + 68 (vtls.c:427)
3   libcurl.4.dylib                 0x0000000104ecd15d global_init + 189 (easy.c:168)
4   libcurl.4.dylib                 0x0000000104ecd029 curl_global_init + 41 (easy.c:223)
5   curl                            0x0000000104e42762 main_init + 114 (tool_main.c:168)
6   curl                            0x0000000104e42447 main + 151 (tool_main.c:277)
7   libdyld.dylib                   0x00007fff57f9e015 start + 1

My guess: Does vtls.c:918 need the same if(Curl_ssl->init) test as vtls.c:426?

curl/lib/vtls/vtls.c

Lines 914 to 919 in 34cf9d5

	static int multissl_init(void)
	{
	if(multissl_setup(NULL))
	return 1;
	return Curl_ssl->init();
	}

curl/lib/vtls/vtls.c

Lines 426 to 428 in 34cf9d5

	if(Curl_ssl->init)
	return Curl_ssl->init();
	return 1;

I expected the following

Able to use secure-transport with multissl.

curl/libcurl version

$ ./src/curl -V
curl 8.12.0 (x86_64-apple-darwin17.7.0) libcurl/8.12.0 OpenSSL/3.3.2 (SecureTransport) zlib/1.3.1 zstd/1.5.6 libidn2/2.3.7 libpsl/0.21.5 nghttp2/1.64.0
Release-Date: 2025-02-05
Protocols: dict file ftp ftps gopher gophers http https imap imaps ipfs ipns ldap ldaps mqtt pop3 pop3s rtsp smb smbs smtp smtps telnet tftp ws wss
Features: alt-svc AsynchDNS HSTS HTTP2 HTTPS-proxy IDN IPv6 Largefile libz MultiSSL NTLM PSL SSL threadsafe TLS-SRP UnixSockets zstd

operating system

$ sw_vers
ProductName: Mac OS X
ProductVersion: 10.13.6
BuildVersion: 17G14042

[jay]

My guess: Does vtls.c:918 need the same if(Curl_ssl->init) test as vtls.c:426?

Makes sense to me. There are 3 SSL backends without an init function: bearssl, rustls and secure-transport.

curl/lib/vtls/vtls.c

Lines 426 to 428 in 34cf9d5

	if(Curl_ssl->init)
	return Curl_ssl->init();
	return 1;

Would you like to test and submit a PR that uses that same logic?