> Normally application create a single SSL_CTX structure before starting
> any threads and muliple SSL structure from that SSL_CTX so that problem
> doesn't arise.
In my app, multiple threads call into the *_client_method structures because
they don't know ahead of time which transport to use. Possibly someone
could add a note to the threads manpage that advises apps to call all the
methods below initially on a single thread.
> I suppose it should be locked though. A simple workaround is to make a
> dummy SSL_v3_client_method() call before starting any threads.
This is the same workaround I eventually came up with.
I needed to add the following calls in my single-thread "openssl setup" code
to end several race conditions:
SSLv23_client_method();
SSLv2_client_method();
SSLv3_client_method();
TLSv1_client_method();
SSLv23_method();
SSLv2_method();
SSLv3_method();
TLSv1_method();
SSLv23_server_method();
SSLv2_server_method();
SSLv3_server_method();
TLSv1_server_method();
ssl2_get_cipher_by_char("XXX");
ssl3_get_cipher_by_char("XXX");
I also see race conditions in crypto/rand/md_rand.c that I don't see a
workaround for. There's an init race in ssleay_rand_bytes. Multiple
threads can call in and end up in the initialization code if init==0. I'm
not sure why there is a lock around "if (init)", since this lock doesn't
prevent multiple initialization.
These threads then both call RAND_seed (ssleay_rand_seed, for me) at once.
ssleay_rand_seed modifies globals without any locking, so it doesn't appear
thread safe.
ssleay_rand_bytes modifies globals (md, md_count, etc.) without locking, so
the random byte buffer can be filled from "md" while another thread is
rewriting the contents of "md". Also, "md_count[0]++" has undefined
results.
I see that access to state_num and state_index is locked, so I'm confused
why the other globals are modified outside of locks.
Thanks for looking at this!
Patrick
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