diff options
author | Lutz Jänicke <jaenicke@openssl.org> | 2001-08-21 13:02:58 +0000 |
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committer | Lutz Jänicke <jaenicke@openssl.org> | 2001-08-21 13:02:58 +0000 |
commit | 336736ef35471888c266336ac2fb17e740979955 (patch) | |
tree | 58a6ae5cff1428efd6df859a2aaf03d84703a019 /doc | |
parent | df7cb13525f49fc3d004405d34cbe321cd42a7d8 (diff) | |
download | openssl-336736ef35471888c266336ac2fb17e740979955.tar.gz |
Documentation on how to handle compression methods.
Hopefully it is clear enough, that it is currently not recommended.
Diffstat (limited to 'doc')
-rw-r--r-- | doc/ssl/SSL_COMP_add_compression_method.pod | 64 | ||||
-rw-r--r-- | doc/ssl/ssl.pod | 1 |
2 files changed, 65 insertions, 0 deletions
diff --git a/doc/ssl/SSL_COMP_add_compression_method.pod b/doc/ssl/SSL_COMP_add_compression_method.pod new file mode 100644 index 0000000000..9e970044a6 --- /dev/null +++ b/doc/ssl/SSL_COMP_add_compression_method.pod @@ -0,0 +1,64 @@ +=pod + +=head1 NAME + +SSL_COMP_add_compression_method - handle SSL/TLS integrated compression methods + +=head1 SYNOPSIS + + #include <openssl/ssl.h> + + int SSL_COMP_add_compression_method(int id, COMP_METHOD *cm); + +=head1 DESCRIPTION + +SSL_COMP_add_compression_method() adds the compression method B<cm> with +the identifier B<id> to the list of available compression methods. This +list is globally maintained for all SSL operations within this application. +It cannot be set for specific SSL_CTX or SSL objects. + +=head1 NOTES + +The TLS standard (or SSLv3) allows the integration of compression methods +into the communication. The TLS RFC does however not specify compression +methods or their corresponding identifiers, so there is currently no compatible +way to integrate compression with unknown peers. It is therefore currently not +recommended to integrate compression into applications. Applications for +non-public use may agree on certain compression methods. Using different +compression methods with the same identifier will lead to connection failure. + +An OpenSSL client speaking a protocol that allows compression (SSLv3, TLSv1) +will unconditionally send the list of all compression methods enabled with +SSL_COMP_add_compression_method() to the server during the handshake. +Unlike the mechanisms to set a cipher list, there is no method available to +restrict the list of compression method on a per connection basis. + +An OpenSSL server will match the identifiers listed by a client against +its own compression methods and will unconditionally activate compression +when a matching identifier is found. There is no way to restrict the list +of compression methods supported on a per connection basis. + +The OpenSSL library has the compression methods B<COMP_rle()> and (when +especially enabled during compilation) B<COMP_zlib()> available. + +=head1 RETURN VALUES + +SSL_COMP_add_compression_method() may return the following values: + +=over 4 + +=item 1 + +The operation succeeded. + +=item 0 + +The operation failed. Check the error queue to find out the reason. + +=back + +=head1 SEE ALSO + +L<ssl(3)|ssl(3)> + +=cut diff --git a/doc/ssl/ssl.pod b/doc/ssl/ssl.pod index bee252aa8b..cb4260ee80 100644 --- a/doc/ssl/ssl.pod +++ b/doc/ssl/ssl.pod @@ -650,6 +650,7 @@ L<openssl(1)|openssl(1)>, L<crypto(3)|crypto(3)>, L<SSL_accept(3)|SSL_accept(3)>, L<SSL_clear(3)|SSL_clear(3)>, L<SSL_connect(3)|SSL_connect(3)>, L<SSL_CIPHER_get_name(3)|SSL_CIPHER_get_name(3)>, +L<SSL_COMP_add_compression_method(3)|SSL_COMP_add_compression_method(3)>, L<SSL_CTX_add_extra_chain_cert(3)|SSL_CTX_add_extra_chain_cert(3)>, L<SSL_CTX_add_session(3)|SSL_CTX_add_session(3)>, L<SSL_CTX_flush_sessions(3)|SSL_CTX_flush_sessions(3)>, |