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Re: instability

Hi Paulo,

Are you using libssh in several threads ? Libssh is threadsafe under two conditions : call ssh_init() outside of threads and initialize threading in the crypto library (http://www.openssl.org/support/faq.html#PROG1). With libssh 0.5, it's a little different, you have to initialize libssh threads and call ssh_init(). (libssh does the dirty work of initilalizing libcrypto or libgcrypt).

Hope this helps,


Le 23/05/11 21:41, Paulo Panhoto a écrit :

I'm writing a Qt app with libssh. The best approach I've got was this:
wrap ssh in a QThread that emits signals to other components.

         session = ssh_new();

         if (session == NULL)
             throw SSHException(tr("ssh_new failed"));
         const std::string & stdHost = host.toStdString();
         ssh_options_set(session, SSH_OPTIONS_HOST, stdHost.c_str());
         ssh_options_set(session, SSH_OPTIONS_PORT, &port);
         ssh_options_set(session, SSH_OPTIONS_SSH1, &disabled);
         ssh_options_set(session, SSH_OPTIONS_SSH2, &enabled);

         emit stateChanged(CONNECTING);
         emit debugInfo(tr("Conecting to %0:%1").arg(host).arg(port));
         if (ssh_connect(session) != SSH_OK)
             throw SSHException(QString("ssh_connect:

This piece of code is causing me trouble: I'm running it on a opensuse
11.3 and tested it with libssh 0.4.2 (the "branding" release) and 0.4.8.

When I compile it against OpenSSL, I get aborts due to double free
inside libcrypto: works most of the time when I run it natively.
Nevertheless, when the program is run via xming server, the error rate
is almost 100%
libopenssl 1.0.0-6.7.1 - x86_64

#0  0x00007ffff5aca9e5 in raise () from /lib64/libc.so.6
#1  0x00007ffff5acbee6 in abort () from /lib64/libc.so.6
#2  0x00007ffff5b05c53 in __libc_message () from /lib64/libc.so.6
#3  0x00007ffff5b0b226 in malloc_printerr () from /lib64/libc.so.6
#4  0x00007ffff5b0e8e3 in _int_realloc () from /lib64/libc.so.6
#5  0x00007ffff5b10142 in realloc () from /lib64/libc.so.6
#6  0x00007ffff4ca6d4f in CRYPTO_realloc () from /lib64/libcrypto.so.1.0.0
#7  0x00007ffff4d0d2a8 in lh_insert () from /lib64/libcrypto.so.1.0.0
#8  0x00007ffff4ca980c in OBJ_NAME_add () from /lib64/libcrypto.so.1.0.0
#9  0x00007ffff4d1a66b in OpenSSL_add_all_digests () from
#10 0x00007ffff7bac3cc in ssh_crypto_init () at
#11 0x00007ffff7bae8f1 in ssh_init () at
#12 0x00007ffff7ba929c in ssh_connect (session=0xc3b8e0)

If I compile it against libgcrypt, it fails all the time due to an
assertion failure --  ath.c:193: _gcry_ath_mutex_lock: Assertion `*lock
== ((ath_mutex_t) 0)' failed.
libgcrypt  1.4.4-6.1 - x86-64

#0  0x00007ffff5ac79e5 in raise () from /lib64/libc.so.6
#1  0x00007ffff5ac8ee6 in abort () from /lib64/libc.so.6
#2  0x00007ffff4fdcaa8 in ?? () from /lib64/libgcrypt.so.11
#3  0x00007ffff4fdd1c7 in ?? () from /lib64/libgcrypt.so.11
#4  0x00007ffff4fd75f6 in ?? () from /lib64/libgcrypt.so.11
#5  0x00007ffff4fd7792 in ?? () from /lib64/libgcrypt.so.11
#6  0x00007ffff7ba8f7b in ssh_crypto_init ()
     at /home/paulo/Downloads/oss-src/libssh-0.4.8/libssh/dh.c:115
#7  0x00007ffff7bab961 in ssh_init ()
     at /home/paulo/Downloads/oss-src/libssh-0.4.8/libssh/init.c:47
#8  0x00007ffff7ba5ebc in ssh_connect (session=0xccf260)
     at /home/paulo/Downloads/oss-src/libssh-0.4.8/libssh/client.c:516

Am I missing any steps?? Is openSSL the best library to compile with??

Any idea is appreciated.



Re: instabilityPaulo Panhoto <paulo.panhoto@xxxxxxxxx>
instabilityPaulo Panhoto <paulo.panhoto@xxxxxxxxx>
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