diff options
Diffstat (limited to 'doc/ssl/SSL_CTX_set_options.pod')
| -rw-r--r-- | doc/ssl/SSL_CTX_set_options.pod | 21 |
1 files changed, 12 insertions, 9 deletions
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 |