@c Copyright (C) 2004 Free Software Foundation, Inc. @c This is part of the GnuPG manual. @c For copying conditions, see the file gnupg.texi. @node Debugging @chapter How to solve problems Everyone knows that software often does not do what it should do and thus there is a need to track down problems. We call this debugging in a reminiscent to the moth jamming a relay in a Mark II box back in 1947. Most of the problems a merely configuration and user problems but nevertheless they are the most annoying ones and responsible for many gray hairs. We try to give some guidelines here on how to identify and solve the problem at hand. @menu * Debugging Tools:: Description of some useful tools. * Debugging Hints:: Various hints on debugging. * Common Problems:: Commonly seen problems. * Architecture Details:: How the whole thing works internally. @end menu @node Debugging Tools @section Debugging Tools The GnuPG distribution comes with a couple of tools, useful to help find and solving problems. @menu * kbxutil:: Scrutinizing a keybox file. @end menu @node kbxutil @subsection Scrutinizing a keybox file A keybox is a file format used to store public keys along with meta information and indices. The commonly used one is the file @file{pubring.kbx} in the @file{.gnupg} directory. It contains all X.509 certificates as well as OpenPGP keys@footnote{Well, OpenPGP keys are not implemented, @command{gpg} still used the keyring file @file{pubring.gpg}.}. @noindent When called the standard way, e.g.: @samp{kbxutil ~/.gnupg/pubring.kbx} @noindent it lists all records (called @acronym{blobs}) with there meta-information in a human readable format. @noindent To see statistics on the keybox in question, run it using @samp{kbxutil --stats ~/.gnupg/pubring.kbx} @noindent and you get an output like: @example Total number of blobs: 99 header: 1 empty: 0 openpgp: 0 x509: 98 non flagged: 81 secret flagged: 0 ephemeral flagged: 17 @end example In this example you see that the keybox does not have any OpenPGP keys but contains 98 X.509 certificates and a total of 17 keys or certificates are flagged as ephemeral, meaning that they are only temporary stored (cached) in the keybox and won't get listed using the usual commands provided by @command{gpgsm} or @command{gpg}. 81 certificates are stored in a standard way and directly available from @command{gpgsm}. @noindent To find duplicated certificates and keyblocks in a keybox file (this should not occur but sometimes things go wrong), run it using @samp{kbxutil --find-dups ~/.gnupg/pubring.kbx} @node Debugging Hints @section Various hints on debugging @itemize @bullet @item How to find the IP address of a keyserver If a round robin URL of is used for a keyserver (e.g. subkeys.gnupg.org); it is not easy to see what server is actually used. Using the keyserver debug option as in @smallexample gpg --keyserver-options debug=1 -v --refresh-key 1E42B367 @end smallexample is thus often helpful. Note that the actual output depends on the backend and may change from release to release. @item Logging on WindowsCE For development, the best logging method on WindowsCE is the use of remote debugging using a log file name of @file{tcp://:}. The command @command{watchgnupg} may be used on the remote host to listen on the given port (@pxref{option watchgnupg --tcp}). For in the field tests it is better to make use of the logging facility provided by the @command{gpgcedev} driver (part of libassuan); this is enabled by using a log file name of @file{GPG2:} (@pxref{option --log-file}). @end itemize @node Common Problems @section Commonly Seen Problems @itemize @bullet @item Error code @samp{Not supported} from Dirmngr Most likely the option @option{enable-ocsp} is active for gpgsm but Dirmngr's OCSP feature has not been enabled using @option{allow-ocsp} in @file{dirmngr.conf}. @item The Curses based Pinentry does not work The far most common reason for this is that the environment variable @code{GPG_TTY} has not been set correctly. Make sure that it has been set to a real tty device and not just to @samp{/dev/tty}; i.e. @samp{GPG_TTY=tty} is plainly wrong; what you want is @samp{GPG_TTY=`tty`} --- note the back ticks. Also make sure that this environment variable gets exported, that is you should follow up the setting with an @samp{export GPG_TTY} (assuming a Bourne style shell). Even for GUI based Pinentries; you should have set @code{GPG_TTY}. See the section on installing the @command{gpg-agent} on how to do it. @item SSH hangs while a popping up pinentry was expected SSH has no way to tell the gpg-agent what terminal or X display it is running on. So when remotely logging into a box where a gpg-agent with SSH support is running, the pinentry will get popped up on whatever display the gpg-agent has been started. To solve this problem you may issue the command @smallexample echo UPDATESTARTUPTTY | gpg-connect-agent @end smallexample and the next pinentry will pop up on your display or screen. However, you need to kill the running pinentry first because only one pinentry may be running at once. If you plan to use ssh on a new display you should issue the above command before invoking ssh or any other service making use of ssh. @item Exporting a secret key without a certificate It may happen that you have created a certificate request using @command{gpgsm} but not yet received and imported the certificate from the CA. However, you want to export the secret key to another machine right now to import the certificate over there then. You can do this with a little trick but it requires that you know the approximate time you created the signing request. By running the command @smallexample ls -ltr ~/.gnupg/private-keys-v1.d @end smallexample you get a listing of all private keys under control of @command{gpg-agent}. Pick the key which best matches the creation time and run the command @cartouche @smallexample @value{LIBEXECDIR}/gpg-protect-tool --p12-export \ ~/.gnupg/private-keys-v1.d/@var{foo} >@var{foo}.p12 @end smallexample @end cartouche (Please adjust the path to @command{gpg-protect-tool} to the appropriate location). @var{foo} is the name of the key file you picked (it should have the suffix @file{.key}). A Pinentry box will pop up and ask you for the current passphrase of the key and a new passphrase to protect it in the pkcs#12 file. To import the created file on the machine you use this command: @cartouche @smallexample @value{LIBEXECDIR}/gpg-protect-tool --p12-import --store @var{foo}.p12 @end smallexample @end cartouche You will be asked for the pkcs#12 passphrase and a new passphrase to protect the imported private key at its new location. Note that there is no easy way to match existing certificates with stored private keys because some private keys are used for Secure Shell or other purposes and don't have a corresponding certificate. @item A root certificate does not verify A common problem is that the root certificate misses the required basicConstraints attribute and thus @command{gpgsm} rejects this certificate. An error message indicating ``no value'' is a sign for such a certificate. You may use the @code{relax} flag in @file{trustlist.txt} to accept the certificate anyway. Note that the fingerprint and this flag may only be added manually to @file{trustlist.txt}. @item Error message: ``digest algorithm N has not been enabled'' The signature is broken. You may try the option @option{--extra-digest-algo SHA256} to workaround the problem. The number N is the internal algorithm identifier; for example 8 refers to SHA-256. @item The Windows version does not work under Wine When running the W32 version of @command{gpg} under Wine you may get an error messages like: @smallexample gpg: fatal: WriteConsole failed: Access denied @end smallexample @noindent The solution is to use the command @command{wineconsole}. Some operations like @option{--generate-key} really want to talk to the console directly for increased security (for example to prevent the passphrase from appearing on the screen). So, you should use @command{wineconsole} instead of @command{wine}, which will launch a windows console that implements those additional features. @item Why does GPG's --search-key list weird keys? For performance reasons the keyservers do not check the keys the same way @command{gpg} does. It may happen that the listing of keys available on the keyservers shows keys with wrong user IDs or with user Ids from other keys. If you try to import this key, the bad keys or bad user ids won't get imported, though. This is a bit unfortunate but we can't do anything about it without actually downloading the keys. @end itemize @c ******************************************** @c *** Architecture Details ***************** @c ******************************************** @node Architecture Details @section How the whole thing works internally @menu * Component interaction:: How the components work together. * GnuPG-1 and GnuPG-2:: Relationship between GnuPG 1.4 and 2.x. @end menu @node Component interaction @subsection How the components work together @float Figure,fig:moduleoverview @caption{GnuPG module overview} @center @image{gnupg-module-overview, 150mm,,GnuPG modules} @end float @node GnuPG-1 and GnuPG-2 @subsection Relationship between GnuPG 1.4 and 2.x Here is a little picture showing how the different GnuPG versions make use of a smartcard: @float Figure,fig:cardarchitecture @caption{GnuPG card architecture} @center @image{gnupg-card-architecture, 150mm,, GnuPG card architecture} @end float