I'm trying to do a proof of concept using Stunnel on AIX 6.1.

Without stunnel I'd have:

Telnet session -> listening service

With stunnel, I want:

telnet session -> stunnel client -[secure connection]--> Stunnel server -->listening service.

The stunnel client seems to be working fine, but the stunnel server abends as soon as it receives a secure connection.

Client:

Accepts non-secure on port 33342. Forwards to secure socket 33343

stunnel stunnel.conf.2 2017.02.21 09:31:35 LOG5[ui]: stunnel 5.40 on powerpc-ibm-aix6.1.0.0 platform 2017.02.21 09:31:35 LOG5[ui]: Compiled/running with OpenSSL 1.0.2j 26 Sep 2016 2017.02.21 09:31:35 LOG5[ui]: Threading:PTHREAD Sockets:POLL,IPv6 TLS:ENGINE,FIPS,OCSP,PSK,SNI 2017.02.21 09:31:35 LOG5[ui]: Reading configuration from file /bmo/stunnel/bin/stunnel.conf.2 2017.02.21 09:31:35 LOG5[ui]: UTF-8 byte order mark detected 2017.02.21 09:31:35 LOG5[ui]: FIPS mode disabled 2017.02.21 09:31:35 LOG6[ui]: Initializing service [hif] 2017.02.21 09:31:35 LOG6[ui]: Loading certificate from file: /bmo/stunnel/stunnel.pem 2017.02.21 09:31:35 LOG6[ui]: Certificate loaded from file: /bmo/stunnel/stunnel.pem 2017.02.21 09:31:35 LOG6[ui]: Loading private key from file: /bmo/stunnel/stunnel.pem 2017.02.21 09:31:35 LOG4[ui]: Insecure file permissions on /bmo/stunnel/stunnel.pem 2017.02.21 09:31:35 LOG6[ui]: Private key loaded from file: /bmo/stunnel/stunnel.pem 2017.02.21 09:31:35 LOG4[ui]: Service [hif] needs authentication to prevent MITM attacks 2017.02.21 09:31:35 LOG5[ui]: Configuration successful 2017.02.21 09:31:38 LOG5[0]: Service [hif] accepted connection from 127.0.0.1:34749 2017.02.21 09:31:38 LOG6[0]: s_connect: connecting 127.0.0.1:33343 2017.02.21 09:31:38 LOG6[0]: s_connect: connected 127.0.0.1:33343 2017.02.21 09:31:38 LOG5[0]: Service [hif] connected remote server from 127.0.0.1:34750 2017.02.21 09:31:38 LOG6[0]: SNI: sending servername: localhost 2017.02.21 09:31:38 LOG6[0]: Peer certificate not required 2017.02.21 09:31:38 LOG3[0]: SSL_connect: Peer suddenly disconnected 2017.02.21 09:31:38 LOG5[0]: Connection reset: 0 byte(s) sent to TLS, 0 byte(s) sent to socket

Server

Accepts SSL connections on port 33343, connects to a non-secure service.

stunnel stunnel.conf.1 2017.02.21 09:31:25 LOG5[ui]: stunnel 5.40 on powerpc-ibm-aix6.1.0.0 platform 2017.02.21 09:31:25 LOG5[ui]: Compiled/running with OpenSSL 1.0.2j 26 Sep 2016 2017.02.21 09:31:25 LOG5[ui]: Threading:PTHREAD Sockets:POLL,IPv6 TLS:ENGINE,FIPS,OCSP,PSK,SNI 2017.02.21 09:31:25 LOG5[ui]: Reading configuration from file /bmo/stunnel/bin/stunnel.conf.1 2017.02.21 09:31:25 LOG5[ui]: UTF-8 byte order mark detected 2017.02.21 09:31:25 LOG5[ui]: FIPS mode disabled 2017.02.21 09:31:25 LOG6[ui]: Initializing service [hif] 2017.02.21 09:31:25 LOG6[ui]: Loading certificate from file: /bmo/stunnel/stunnel.pem 2017.02.21 09:31:25 LOG6[ui]: Certificate loaded from file: /bmo/stunnel/stunnel.pem 2017.02.21 09:31:25 LOG6[ui]: Loading private key from file: /bmo/stunnel/stunnel.pem 2017.02.21 09:31:25 LOG4[ui]: Insecure file permissions on /bmo/stunnel/stunnel.pem 2017.02.21 09:31:25 LOG6[ui]: Private key loaded from file: /bmo/stunnel/stunnel.pem 2017.02.21 09:31:25 LOG5[ui]: Configuration successful 2017.02.21 09:31:38 LOG5[0]: Service [hif] accepted connection from 127.0.0.1:34750 2017.02.21 09:31:38 LOG6[0]: Peer certificate not required INTERNAL ERROR: Bad magic at OpenSSL, line 0

(this is an abend - core file gets created).

log file exactly matches the standard output.

Any idea what's going wrong here?

dbx of the core file: tbs@netcbccadvwvr01 /bmo/hif/stunnel-5.40/src>dbx /bmo/stunnel/bin/stunnel core Type 'help' for help. [using memory image in core] reading symbolic information ...

IOT/Abort trap in abort at 0xd01af1f8 ($t3) 0xd01af1f8 (abort+0xf8) 80410014 lwz r2,0x14(r1)

(dbx) where abort() at 0xd01af1f8 fatal_debug(txt = "Bad magic", file = "OpenSSL", line = 0), line 359 in "log.c" get_alloc_list_ptr(ptr = 0x2007e1c8, file = "OpenSSL", line = 0), line 399 in "str.c" str_detach_debug(ptr = 0x2007e1c8, file = "OpenSSL", line = 0), line 348 in "str.c" str_free_debug(ptr = 0x2007e1c8, file = "OpenSSL", line = 0), line 383 in "str.c" free_function(ptr = 0x2007e1c8), line 191 in "tls.c" mem.CRYPTO_free() at 0xd97dd8d8 bn_lib.bn_expand2@AF37_5() at 0xd97e8da4 bn_mont.BN_mod_mul_montgomery() at 0xd981e150 ecp_mont.ec_GFp_mont_field_mul() at 0xd9837a18 ecp_smpl.ec_GFp_simple_point_get_affine_coordinates() at 0xd9839890 ec_lib.EC_POINT_get_affine_coordinates_GFp() at 0xd9a81dfc ecp_oct.ec_GFp_simple_point2oct() at 0xd9acc0d4 ec_oct.EC_POINT_point2oct() at 0xd9acb754 ssl3_send_server_key_exchange() at 0xd99e7c28 ssl3_accept() at 0xd99e9950 SSL_accept() at 0xd99c0b98 ssl23_get_client_hello() at 0xd9a003f4 ssl23_accept() at 0xd9a00c5c SSL_accept() at 0xd99c0b98 ssl_start(c = 0x20084cb8), line 431 in "client.c" client_try(c = 0x20084cb8), line 273 in "client.c" client_run(c = 0x20084cb8), line 181 in "client.c" client_main(c = 0x20084cb8), line 140 in "client.c" client_thread(arg = 0x20084cb8), line 99 in "client.c"

(dbx) thread thread state-k wchan state-u k-tid mode held scope function $t1 run running 26279997 u no sys __fd_poll $t2 run running 45088879 u no sys _p_nsleep

$t3 run running 19070997 k no sys abort

(dbx) list free_function 186 187 #if OPENSSL_VERSION_NUMBER<0x10100000L 188 NOEXPORT void free_function(void *ptr) { 189 /* CRYPTO_set_mem_ex_functions() needs a function rather than a macro */ 190 /* unfortunately, OpenSSL provides no file:line information here */ 191 str_free_debug(ptr, "OpenSSL", 0); 192 } 193 #endif 194 195 /* end of tls.c */

Should I be concerned that it looks like it is executing "free_function" from within an if statement "if OPENSSL_VERSION_NUMBER<0x1010000L but my openssl version is 2017.02.21 09:31:35 LOG5[ui]: Compiled/running with OpenSSL 1.0.2j 26 Sep 2016

Troubleshooting so far:

- I had the same problem with earlier versions of openssl.

- I've tried this with 5.37 as well (based on Brian McGinity's post from a few days ago), but get the same error.

Jacob