Hi. This issue is not present in 1.0.1k or earlier (my code has worked for
years), and is in 1.0.2 and 1.0.2a. I do not have any simple reproducer as
it comes from a moderately esoteric environment using asynchronous BIO
written for [Open]VMS.
The server initiates the SSL listening context using:
if (!(SSLversion & SESOLA_SSLV2)) SSLoptions |= SSL_OP_NO_SSLv2;
if (!(SSLversion & SESOLA_SSLV3)) SSLoptions |= SSL_OP_NO_SSLv3;
if (!(SSLversion & SESOLA_TLSV1)) SSLoptions |= SSL_OP_NO_TLSv1;
if (!(SSLversion & SESOLA_TLSV1_1)) SSLoptions |= SSL_OP_NO_TLSv1_1;
if (!(SSLversion & SESOLA_TLSV1_2)) SSLoptions |= SSL_OP_NO_TLSv1_2;
SslCtx = SSL_CTX_new (SSLv23_method());
(i.e. options-off any non-desired protocol versions)
The problem was induced on the command-line:
openssl s_client -ssl3 -host <whichever> -port 443
Trace data from the program shows:
|00:53:29.08 SESOLANE 0214 0001 SSL BEGIN|
|00:53:29.08 SESOLA 2606 0001 SSL start handshake|
|00:53:29.08 SESOLA 2583 0001 SSL SSL_ACCEPT before/accept
initialization|
|00:53:29.08 SESOLA 2686 0001 SSL READ 11/-1 (outstanding)|
|00:53:29.08 SESOLA 2593 0001 SSL SSL_ACCEPT error/blocking in
SSLv2/v3 read client hello A|
|00:53:29.08 SESOLA 2686 0001 SSL READ 11/11 (complete)|
|00:53:29.08 SESOLA 2700 0001 SSL CTRL 6 0|
|00:53:29.08 SESOLA 2686 0001 SSL READ 147/-1 (outstanding)|
|00:53:29.08 SESOLA 2593 0001 SSL SSL_ACCEPT error/blocking in SSLv3
read client hello B|
|00:53:29.08 SESOLA 2593 0001 SSL SSL_ACCEPT error/blocking in SSLv3
read client hello B|
|00:53:29.09 SESOLA 2686 0001 SSL READ 147/147 (complete)|
|00:53:29.09 SESOLA 2691 0001 SSL WRITE 7/-1 (outstanding)|
|00:53:29.09 SESOLA 2602 0001 SSL SSL_BEFORE write SSLv3 read client
hello C|
|00:53:29.09 SESOLA 2593 0001 SSL SSL_ACCEPT error/blocking in SSLv3
read client hello C|
and then without my workaround segmentation faults, apparently when the NULL
session is dereferenced by ssl3_choose_cipher().
My workaround in s3_svr.c looks like:
#define MGD_150321
#ifdef MGD_150321
/***
OpenSSL v1.0.2 and v1.0.2a ACCVIOs in s3_srvr.c ssl3_get_client_hello()
at ssl3_choose_cipher() when SSLv3 is not enabled with an SSLv3 client!
OpenSSL v1.0.1k s3_srvr.c ssl3_get_client_hello() is fine!!
This seems to be a NULL session being dereferenced here!
***/
if (s->session == NULL)
c = NULL;
else
#endif /* MGD_150321 */
c = ssl3_choose_cipher(s, s->session->ciphers, SSL_get_ciphers(s));
which avoids the issue but the resulting trace data suggests not elegantly.
The underlying issue must be upstream in the processing.
Trust this is of some assistance.
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