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authorDr. Stephen Henson <steve@openssl.org>2010-02-17 18:38:10 +0000
committerDr. Stephen Henson <steve@openssl.org>2010-02-17 18:38:10 +0000
commit989238802aa096c083dd78d0add49ef67dc073da (patch)
tree2aea6e3370833f4090ce0e05ff686dbdac62474b
parent9051fc538f93393d9e5540c9f981858178f5a1c1 (diff)
downloadopenssl-new-989238802aa096c083dd78d0add49ef67dc073da.tar.gz
Allow renegotiation if SSL_OP_LEGACY_SERVER_CONNECT is set as well as
initial connection to unpatched servers. There are no additional security concerns in doing this as clients don't see renegotiation during an attack anyway.
-rw-r--r--CHANGES2
-rw-r--r--doc/ssl/SSL_CTX_set_options.pod21
-rw-r--r--ssl/t1_lib.c4
3 files changed, 15 insertions, 12 deletions
diff --git a/CHANGES b/CHANGES
index 6ffa4d83a4..947962fffd 100644
--- a/CHANGES
+++ b/CHANGES
@@ -877,7 +877,7 @@
[Bodo Moeller]
*) Add option SSL_OP_LEGACY_SERVER_CONNECT which will allow clients to
- connect (but not renegotiate) with servers which do not support RI.
+ connect and renegotiate with servers which do not support RI.
Until RI is more widely deployed this option is enabled by default.
[Steve Henson]
diff --git a/doc/ssl/SSL_CTX_set_options.pod b/doc/ssl/SSL_CTX_set_options.pod
index 3e61a36e17..1abda2898e 100644
--- a/doc/ssl/SSL_CTX_set_options.pod
+++ b/doc/ssl/SSL_CTX_set_options.pod
@@ -237,7 +237,7 @@ OpenSSL 0.9.8m and later always attempts to use secure renegotiation as
described in RFC5746. This counters the prefix attack described in
CVE-2009-3555 and elsewhere.
-The deprecated and highly broken SSLv2 protocol does not support secure
+The deprecated and highly broken SSLv2 protocol does not support
renegotiation at all: its use is B<strongly> discouraged.
This attack has far reaching consequences which application writers should be
@@ -276,10 +276,14 @@ was refused.
=head2 Patched OpenSSL client and unpatched server.
If the option B<SSL_OP_LEGACY_SERVER_CONNECT> is set then initial connections
-between patched OpenSSL clients and unpatched servers succeed. This option
-is currently set by default even though it has security implications: otherwise
-it would be impossible to connect to unpatched servers (i.e. all of them
-initially) and this is clearly not acceptable.
+and renegotiation between patched OpenSSL clients and unpatched servers
+succeeds.
+
+This option is currently set by default even though it has security
+implications: otherwise it would be impossible to connect to unpatched servers
+(i.e. all of them initially) and this is clearly not acceptable. Renegotiation
+is permitted because this does not add any additional security issues: during
+an attack clients do not see any renegotiations anyway.
As more servers become patched the option B<SSL_OP_LEGACY_SERVER_CONNECT> will
B<not> be set by default in a future version of OpenSSL.
@@ -292,10 +296,9 @@ unpatched servers (and thus avoid any security issues) should always B<clear>
B<SSL_OP_LEGACY_SERVER_CONNECT> using SSL_CTX_clear_options() or
SSL_clear_options().
-Renegotiation between a patched OpenSSL client and unpatched server follows
-the same scheme as between an unpatched client and a patched OpenSSL server:
-i.e. it is not permitted unless the option
-B<SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION> is set.
+As in the previous case if the option
+B<SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION> is set then renegotiation
+B<always> succeeds.
=head1 RETURN VALUES
diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c
index 4cb171e6d4..e8bc34c111 100644
--- a/ssl/t1_lib.c
+++ b/ssl/t1_lib.c
@@ -1157,8 +1157,8 @@ int ssl_parse_serverhello_tlsext(SSL *s, unsigned char **p, unsigned char *d, in
* which doesn't support RI so for the immediate future tolerate RI
* absence on initial connect only.
*/
- if (!renegotiate_seen &&
- (s->new_session || !(s->options & SSL_OP_LEGACY_SERVER_CONNECT))
+ if (!renegotiate_seen
+ && !(s->options & SSL_OP_LEGACY_SERVER_CONNECT)
&& !(s->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION))
{
*al = SSL_AD_HANDSHAKE_FAILURE;