generic-library/openssl
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reword RI description

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This commit is contained in:
Dr. Stephen Henson 2010-01-27 18:53:33 +00:00
parent c2963f5b87
commit 9fb6fd34f8
2 changed files with 32 additions and 22 deletions
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3
crypto/engine/engine.h
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@ -678,6 +678,7 @@ typedef struct st_dynamic_fns {
* can be fully instantiated with IMPLEMENT_DYNAMIC_CHECK_FN(). */ * can be fully instantiated with IMPLEMENT_DYNAMIC_CHECK_FN(). */
typedef unsigned long (*dynamic_v_check_fn)(unsigned long ossl_version); typedef unsigned long (*dynamic_v_check_fn)(unsigned long ossl_version);
#define IMPLEMENT_DYNAMIC_CHECK_FN() \ #define IMPLEMENT_DYNAMIC_CHECK_FN() \
OPENSSL_EXPORT unsigned long v_check(unsigned long v); \
OPENSSL_EXPORT unsigned long v_check(unsigned long v) { \ OPENSSL_EXPORT unsigned long v_check(unsigned long v) { \
if(v >= OSSL_DYNAMIC_OLDEST) return OSSL_DYNAMIC_VERSION; \ if(v >= OSSL_DYNAMIC_OLDEST) return OSSL_DYNAMIC_VERSION; \
return 0; } return 0; }
@ -700,6 +701,8 @@ typedef unsigned long (*dynamic_v_check_fn)(unsigned long ossl_version);
typedef int (*dynamic_bind_engine)(ENGINE *e, const char *id, typedef int (*dynamic_bind_engine)(ENGINE *e, const char *id,
const dynamic_fns *fns); const dynamic_fns *fns);
#define IMPLEMENT_DYNAMIC_BIND_FN(fn) \ #define IMPLEMENT_DYNAMIC_BIND_FN(fn) \
OPENSSL_EXPORT \
int bind_engine(ENGINE *e, const char *id, const dynamic_fns *fns);
OPENSSL_EXPORT \ OPENSSL_EXPORT \
int bind_engine(ENGINE *e, const char *id, const dynamic_fns *fns) { \ int bind_engine(ENGINE *e, const char *id, const dynamic_fns *fns) { \
if(ENGINE_get_static_state() == fns->static_state) goto skip_cbs; \ if(ENGINE_get_static_state() == fns->static_state) goto skip_cbs; \

51
doc/ssl/SSL_CTX_set_options.pod
View File

@ -237,24 +237,30 @@ OpenSSL 0.9.8m and later always attempts to use secure renegotiation as
described in draft-ietf-tls-renegotiation (FIXME: replace by RFC). This described in draft-ietf-tls-renegotiation (FIXME: replace by RFC). This
counters the prefix attack described in CVE-2009-3555 and elsewhere. counters the prefix attack described in CVE-2009-3555 and elsewhere.
The deprecated and highly broken SSLv2 protocol does not support secure
renegotiation at all: its use is B<strongly> discouraged.
This attack has far reaching consequences which application writers should be This attack has far reaching consequences which application writers should be
aware of. In the description below an implementation supporting secure aware of. In the description below an implementation supporting secure
renegotiation is referred to as I<patched>. A server not supporting secure renegotiation is referred to as I<patched>. A server not supporting secure
renegotiation is referred to as I<unpatched>. renegotiation is referred to as I<unpatched>.
The following sections describe the operations permitted by OpenSSL's secure
renegotiation implementation.
=head2 Patched client and server =head2 Patched client and server
Connections and renegotiation will always succeed. Connections and renegotiation are always permitted by OpenSSL implementations.
=head2 Unpatched client and patched server =head2 Unpatched client and patched OpenSSL server
The initial connection suceeds but client renegotiation is denied with a The initial connection suceeds but client renegotiation is denied by the
B<no_renegotiation> warning alert if TLS v1.0 is used or a fatal server with a B<no_renegotiation> warning alert if TLS v1.0 is used or a fatal
B<handshake_failure> alert in SSL v3.0. B<handshake_failure> alert in SSL v3.0.
If the patched server attempts to renegotiate a fatal B<handshake_failure> If the patched OpenSSL server attempts to renegotiate a fatal
alert is sent. This is because the server code may be unaware of the B<handshake_failure> alert is sent. This is because the server code may be
unpatched nature of the client. unaware of the unpatched nature of the client.
If the option B<SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION> is set then If the option B<SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION> is set then
renegotiation B<always> succeeds. renegotiation B<always> succeeds.
@ -263,32 +269,33 @@ B<NB:> a bug in OpenSSL clients earlier than 0.9.8m (all of which are
unpatched) will result in the connection hanging if it receives a unpatched) will result in the connection hanging if it receives a
B<no_renegotiation> alert. OpenSSL versions 0.9.8m and later will regard B<no_renegotiation> alert. OpenSSL versions 0.9.8m and later will regard
a B<no_renegotiation> alert as fatal and respond with a fatal a B<no_renegotiation> alert as fatal and respond with a fatal
B<handshake_failure> alert. B<handshake_failure> alert. This is because the OpenSSL API currently has
no provision to indicate to an application that a renegotiation attempt
was refused.
=head2 Patched client and unpatched server. =head2 Patched OpenSSL client and unpatched server.
If the option B<SSL_OP_LEGACY_SERVER_CONNECT> is set then initial connections If the option B<SSL_OP_LEGACY_SERVER_CONNECT> is set then initial connections
to unpatched servers succeed. This option is currently set by default even between patched OpenSSL clients and unpatched servers succeed. This option
though it has security implications: otherwise it would be impossible to is currently set by default even though it has security implications: otherwise
connect to unpatched servers i.e. all of them initially and this is clearly not it would be impossible to connect to unpatched servers (i.e. all of them
acceptable. initially) and this is clearly not acceptable.
As more servers become patched the option B<SSL_OP_LEGACY_SERVER_CONNECT> will 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. B<not> be set by default in a future version of OpenSSL.
Applications that want to ensure they can connect to unpatched servers should OpenSSL client applications wishing to ensure they can connect to unpatched
always B<set> B<SSL_OP_LEGACY_SERVER_CONNECT> servers should always B<set> B<SSL_OP_LEGACY_SERVER_CONNECT>
Applications that want to ensure they can B<not> connect to unpatched servers OpenSSL client applications that want to ensure they can B<not> connect to
(and thus avoid any security issues) should always B<clear> unpatched servers (and thus avoid any security issues) should always B<clear>
B<SSL_OP_LEGACY_SERVER_CONNECT> using SSL_CTX_clear_options() or B<SSL_OP_LEGACY_SERVER_CONNECT> using SSL_CTX_clear_options() or
SSL_clear_options(). SSL_clear_options().
The function SSL_get_secure_renegotiation_support() indicates whether the peer Renegotiation between a patched OpenSSL client and unpatched server follows
supports secure renegotiation. the same scheme as between an unpatched client and a patched OpenSSL server:
i.e. it is not permitted unless the option
The deprecated and highly broken SSLv2 protocol does not support secure B<SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION> is set.
renegotiation at all: its use is B<strongly> discouraged.
=head1 RETURN VALUES =head1 RETURN VALUES