diff options
author | Bodo Möller <bodo@openssl.org> | 2007-09-21 06:54:24 +0000 |
---|---|---|
committer | Bodo Möller <bodo@openssl.org> | 2007-09-21 06:54:24 +0000 |
commit | 761772d7e19145fa9afb2a0c830ead69a33f3fa5 (patch) | |
tree | f6fbfed11e54a5286025bf235889cca1cb87d503 /CHANGES | |
parent | 54ef01b54bd64fdf5820d3860f4c458a9c2fa4f0 (diff) |
Implement the Opaque PRF Input TLS extension
(draft-rescorla-tls-opaque-prf-input-00.txt), and do some cleanups and
bugfixes on the way. In particular, this fixes the buffer bounds
checks in ssl_add_clienthello_tlsext() and in ssl_add_serverhello_tlsext().
Note that the opaque PRF Input TLS extension is not compiled by default;
see CHANGES.
Diffstat (limited to 'CHANGES')
-rw-r--r-- | CHANGES | 58 |
1 files changed, 58 insertions, 0 deletions
@@ -4,6 +4,64 @@ Changes between 0.9.8f and 0.9.9 [xx XXX xxxx] + *) Implement Opaque PRF Input TLS extension as specified in + draft-rescorla-tls-opaque-prf-input-00.txt. Since this is not an + official specification yet and no extension type assignment by + IANA exists, this extension (for now) will have to be explicitly + enabled when building OpenSSL by providing the extension number + to use. For example, specify an option + + -DTLSEXT_TYPE_opaque_prf_input=0x9527 + + to the "config" or "Configure" script to enable the extension, + assuming extension number 0x9527 (which is a completely arbitrary + and unofficial assignment based on the MD5 hash of the Internet + Draft). Note that by doing so, you potentially lose + interoperability with other TLS implementations since these might + be using the same extension number for other purposes. + + SSL_set_tlsext_opaque_prf_input(ssl, src, len) is used to set the + opaque PRF input value to use in the handshake. This will create + an interal copy of the length-'len' string at 'src', and will + return non-zero for success. + + To get more control and flexibility, provide a callback function + by using + + SSL_CTX_set_tlsext_opaque_prf_input_callback(ctx, cb) + SSL_CTX_set_tlsext_opaque_prf_input_callback_arg(ctx, arg) + + where + + int (*cb)(SSL *, void *peerinput, size_t len, void *arg); + void *arg; + + Callback function 'cb' will be called in handshakes, and is + expected to use SSL_set_tlsext_opaque_prf_input() as appropriate. + Argument 'arg' is for application purposes (the value as given to + SSL_CTX_set_tlsext_opaque_prf_input_callback_arg() will directly + be provided to the callback function). The callback function + has to return non-zero to report success: usually 1 to use opaque + PRF input just if possible, or 2 to enforce use of the opaque PRF + input. In the latter case, the library will abort the handshake + if opaque PRF input is not successfully negotiated. + + Arguments 'peerinput' and 'len' given to the callback function + will always be NULL and 0 in the case of a client. A server will + see the client's opaque PRF input through these variables if + available (NULL and 0 otherwise). Note that if the server + provides an opaque PRF input, the length must be the same as the + length of the client's opaque PRF input. + + Note that the callback function will only be called when creating + a new session (session resumption can resume whatever was + previously negotiated), and will not be called in SSL 2.0 + handshakes; thus, SSL_CTX_set_options(ctx, SSL_OP_NO_SSLv2) or + SSL_set_options(ssl, SSL_OP_NO_SSLv2) is especially recommended + for applications that need to enforce opaque PRF input. + + [Bodo Moeller] + *) Update ssl code to support digests other than SHA1+MD5 for handshake MAC. |