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diff --git a/docs/README.sslcerts b/docs/README.sslcerts deleted file mode 100644 index 39c3dcda..00000000 --- a/docs/README.sslcerts +++ /dev/null @@ -1,265 +0,0 @@ - Lynx SSL support for certificates - README.sslcerts file - -BACKGROUND: - -The original README.ssl document for lynx stated: - - Note that the server... may not have a valid certificate. Lynx will not - complain, as it does not yet support certificates... - -Such lack of support is no longer the case. Lynx now features excellent -certificate management through the openssl project. There is almost no -online documentation available regarding how to use openssl's certificate -management with other programs, so this will accompany lynx and hopefully -encourage good practical security for unix clients. - -Lynx relies on openssl to not only encrypt connections over https, but also to -determine whether it should even accept a certificate and establish a secure -connection with a remote host. Because of this reliance upon openssl by lynx, -most of this tutorial deals with how to use openssl to "install" both -vendor-provided CA cert bundles as well as self-signed certs from trusted sources -and, most importantly, how to get them recognized by lynx. - -While lynx on many systems will transparently accept valid certificates, not -all systems enjoy such functionality. Further, as noted above, older versions -of lynx do not perform any validity checks on a certificate. - -There is also the common case of wanting to trust, use and install a -self-signed certificate from a known server source and have it be trusted by -client programs. - -Briefly, the procedure will involve confirming the default system location for -certificates, setting values for SSL_CERT_DIR and SSL_CERT_FILE in -the environment, and converting and hashing the certificates using openssl -utilities to enable recognition. - -THE CURRENT SITUATION: - -Prior to lynx2.8.5dev9, lynx did not check at all for certificate validity. - -Since lynx2.8.5.dev9, lynx has reported this openssl error: - -SSL error:unable to get local issuer certificate-Continue? (y) - -whenever an https connection was initiated and the certificate could not be -found, for whatever reason, by openssl, and therefore lynx. - -This checking for a certificate is an enhancement to security, but rather -tediously generates errors at each https browser request. - -The ability to turn off reporting of this error to the user was added to -lynx2.8.5dev16 as the FORCE_SSL_PROMPT setting in lynx.cfg as noted in the -CHANGELOG: - - This lets the user decide whether to ignore prompting for questionable - aspects of an SSL connection. - -While this is a convenient setting to employ when using lynx to script -https -dumps, it by definition ignores the issue of certificate validity -altogether. Those concerned with proper certificate management and -the maintenance of a store of updated CA certificates will be uncomfortable -with this relaxed security setting. - -The ability to accept a 'wildcard' certificate, where the first character -is a '*' was added to lynx2.8.6dev18. - -PRELIMINARY PROCEDURES: - -It is assumed that openssl has been installed correctly, that the default -cert directory is /usr/local/ssl/certs, (it's often /etc/ssl/certs, but we -need a point of departure for the discussion) and that lynx has been compiled ---with-ssl. - -The default location for certs on your system may be different, or there may not -be one. You will have to substitute that location for /usr/local/ssl/certs in -the following instructions, and/or set environment variables. - -To determine the default location for certs on your system you may run the -following command: - -strings libcrypto.a | grep -in cert | less - -Look in this output for SSL_CERT_DIR and SSL_CERT_FILE, and the lines just -above them. This is your default location, respectively, for certificates, -and the CA cert bundle, cert.pem. You will need to know where libcrypto.a is -found of course. - -Example output: - -<snip> -7490:/etc/ssl/certs -7491:/etc/ssl/cert.pem -7492:SSL_CERT_DIR -7493:SSL_CERT_FILE -<snip> - -Other possible example output: - -<snip> -31555:/usr/local/ssl/certs -31556:/usr/local/ssl/cert.pem -31557:SSL_CERT_DIR -31558:SSL_CERT_FILE -<snip> - -Note that when OpenSSL is installed, the c_rehash utility is installed in a -bin directory (default /usr/local/ssl/bin). You will need to know where it -is on your system. The command: - -whereis c_rehash - -will probably give useful results. - -Note also that there is no CA cert bundle distributed with OpenSSL. The -OpenSSL team specifically decided NOT to do that. Getting a set of trusted -certificates is left up to the installer. - -It is no longer a fairly trivial procedure to pull the bundle of trusted root certs out -of a recent version of Internet Explorer. Multiple certificates are no longer -exportable as a DER formatted file; extraction of a single certificate is the only -export for DER, and DER is what converts to PEM. - -Users with access to Apple OS X can export all certificates from Keychain Access System Roots as -a .pem file. Place this in SSL_CERT_DIR and hash it and you're done. - -The MirOS BSD project also provides them. The procedure to convert and install them -is detailed later in this document, and if you simply need to have commercially provided -certificates trusted by lynx, you can skip down a few lines to the INSTALLING OR UPDATING -THE CA BUNDLE section. - -Extracted Mozilla cert bundles are available for download from the curl project, -http://curl.haxx.se/docs/caextract.html along with a script to extract from Mozilla -source. - - -INSTALLING A SELF-SIGNED CERTIFICATE: - -When you would like to trust a self-signed (non-commercial) certificate you will -need to get hold of the actual file. If it's a cert local to your network you -can ask the sysadmin to make it available for download as a link on a webpage. - -If such file is not human-readable it's probably DER formatted and will need to -be converted to PEM format to allow openssl to use it. - -To convert DER formatted certificates into something openssl can deal with: - -Save the cert as site_name.crt in a directory. In that directory, type: - -openssl x509 -inform DER -in site_name.crt -outform PEM -out site_name.pem - -You can now copy this individual cert into the directory for that, usually -/usr/local/ssl/certs. The alternative is to concatenate the individual certs -to the cert.pem bundle in /usr/local/ssl. (Please see INSTALLING OR UPDATING -THE CA BUNDLE below). - -The cert file will now be in an acceptable format to openssl, PEM encoded. -However, openssl, and by extension lynx, will not know about it until that -cert is symbolically linked to a file named after the hash value of that cert, -in the default directory /usr/local/ssl/certs. - -So the next thing to do is to hash the cert using c_rehash. - -INSTALLING OR UPDATING THE CA BUNDLE: - -Now would be a good time to check to see if you have the bundle of CA certs -/usr/local/ssl/cert.pem, or to update them. - -CA bundles are available in various places, such as the MirOS BSD distribution, -for those who want to take that route, or you can extract the current bundle -from a current version of Internet Explorer (export them all from IE and -transfer it onto your system). - -From MirOS, a cert bundle is available at - -http://caunter.ca/ssl.certs.shar - -It includes the cacert.org certificate. Download the latest revision; read the -file to see how to get the certs out. - -No hashing is necessary with this set of certs; it is already done; ignore -the c_rehash usage below for this bundle. Simply run `sh ssl.certs.shar` -in SSL_CERT_DIR. - -From IE 5.x certs extract as a PKCS7 file and need to be converted with something -like: - -openssl pkcs7 -inform DER -in bundle.crt -outform PEM -out cert.pem \ --print_certs -text - -The resulting cert.pem file should be copied to the default directory for -bundles (usually /usr/local/ssl) and renamed to "cert.pem", assuming that is -the SSL_CERT_FILE. - -Individual certs can also process if added and hashed in /usr/local/ssl/certs. - -We now have all of the individual certs we wish to trust in our certs -directory, and the most recent bundle of CA certs as well. - -Confirm that you have the script c_rehash (See PRELIMINARY PROCEDURES; if it is -not found, a copy is usually located in the tools directory of the openssl -source tree. If you use this copy, it needs the execute bit set or it will not -run). - -Run: - -./c_rehash - -The c_rehash utility is a perl script that runs openssl commands which creates -the files named after the hash values of the certs in the default directory -for certs. - -Its output looks like this: - -Doing /usr/local/ssl/certs -vsignss.pem => f73e89fd.0 -vsign3.pem => 7651b327.0 -...more output -<snip> - -All pem encoded certs in /usr/local/ssl/certs will now be recognized. - -SETTING AND EXPORTING ENVIRONMENT VARIABLES: - -If lynx is still not recognizing certs, environment variables need -to be set; if on a sh type shell, the variables also need to be exported. - -The environment variables SSL_CERT_DIR and SSL_CERT_FILE need to be set -if a non-default location is used for certificates, or if certs just can't be -found by lynx. They may be set as follows in /etc/profile, or a shell -initialization .profile or .*shrc, if we run a non csh type shell, according -to the results of the search for the default location for certs procedure -(See PRELIMINARY PROCEDURES): - -SSL_CERT_DIR="/usr/local/ssl/certs" -SSL_CERT_FILE="/usr/local/ssl/cert.pem" -export SSL_CERT_DIR SSL_CERT_FILE - -On csh type shells, you can use: -setenv SSL_CERT_DIR "/usr/local/ssl/certs" -setenv SSL_CERT_FILE "/usr/local/ssl/cert.pem" - -Note that the environment variable SSL_CERT_FILE applies to the cert-bundle -if used outside of the default location (/usr/local/ssl/cert.pem) compiled -into OpenSSL. There are issues with SSL_CERT_FILE in 0.9.6x versions of openssl. - -The configuration file lynx.cfg allows a system SSL_CERT_FILE variable to be set -which can simplify matters. - -SSL_CERT_FILE:/etc/ssl/certs/ca-certificates.crt - -Make sure you have FORCE_SSL_PROMPT set to PROMPT in lynx.cfg like so: - -FORCE_SSL_PROMPT:PROMPT - -You will now connect without error to https servers with trusted certs, but -will still get this error for untrusted certs: - -SSL error:self signed certificate-Continue? (y) - -A quick check confirms that these procedures have the same effect with ssl -errors in the pine program. - -2003 updated 2009 -Stefan Caunter <stefan.caunter@mohawkcollege.ca> -Mohawk College Department of Computer Science -Hamilton Ontario Canada |