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Diffstat (limited to '')
| -rw-r--r-- | doc/ChangeLog | 4 | ||||
| -rw-r--r-- | doc/Makefile.am | 3 | ||||
| -rw-r--r-- | doc/examples/gpgconf.conf | 59 | ||||
| -rw-r--r-- | doc/gpg-agent.texi | 2 | ||||
| -rw-r--r-- | doc/tools.texi | 30 | ||||
| -rw-r--r-- | doc/vuln-announce-2007-multiple-message.txt | 145 |
6 files changed, 241 insertions, 2 deletions
diff --git a/doc/ChangeLog b/doc/ChangeLog index aff5149c6..799906988 100644 --- a/doc/ChangeLog +++ b/doc/ChangeLog @@ -1,3 +1,7 @@ +2007-03-06 Werner Koch <[email protected]> + + * examples/gpgconf.conf: New. + 2007-03-04 David Shaw <[email protected]> * gpg.texi (GPG Esoteric Options): Document diff --git a/doc/Makefile.am b/doc/Makefile.am index c93df6fad..9614b222b 100644 --- a/doc/Makefile.am +++ b/doc/Makefile.am @@ -19,7 +19,8 @@ ## Process this file with automake to produce Makefile.in -examples = examples/README examples/scd-event examples/trustlist.txt +examples = examples/README examples/scd-event examples/trustlist.txt \ + examples/gpgconf.conf EXTRA_DIST = DETAILS HACKING TRANSLATE OpenPGP KEYSERVER samplekeys.asc \ gnupg-badge-openpgp.eps gnupg-badge-openpgp.jpg \ diff --git a/doc/examples/gpgconf.conf b/doc/examples/gpgconf.conf new file mode 100644 index 000000000..194ed7938 --- /dev/null +++ b/doc/examples/gpgconf.conf @@ -0,0 +1,59 @@ +# gpgconf.conf - configuration for gpgconf +#---------------------------------------------------------------------- +# This file is read by gpgconf(1) to setup defaults for all or +# specified users and groups. It may be used to change the hardwired +# defaults in gpgconf and to enforce certain values for the various +# GnuPG related configuration files. +# +# Empty lines and comment lines, indicated by a hash mark as first non +# white space character, are ignored. The line is separated by white +# space into fields. The first field is used to match the user or +# group and must start at the first column, the file is processes +# sequential until a matching rle is found. A rule may contain +# several lines, continuation lines are indicated by a indenting them. +# +# Syntax of a line: +# <key>|WS <component> <option> ["["<flag>"]"] [<value>] +# +# Examples for the <key> field: +# foo - Matches the user "foo". +# foo: - Matches the user "foo". +# foo:staff - Matches the user "foo" or the group "staff". +# :staff - Matches the group "staff". +# * - Matches any user. +# All other variants are not defined and reserved for future use. +# +# <component> and <option> are as specified by gpgconf. +# <flag> may be one of: +# default - Delete the option so that the default is used. +# no-change - Mark the field as non changeable by gpgconf. +# change - Mark the field as changeable by gpgconf. +# +# Example file: +#========== +# :staff gpg-agent allow-mark-trusted [change] +# gpg-agent min-passphrase-len 6 +# +# * gpg-agent min-passphrase-len [no-change] 12 +# gpg-agent allow-mark-trusted [default] +# gpg-agent allow-mark-trusted [no-change] +# gpgsm enable-ocsp +#=========== +# All users in the group "staff" are allowed to change the value for +# --allow-mark-trusted; gpgconf's default is not to allow a change +# through its interface. When "gpgconf --apply-defaults" is used, +# "allow-mark-trusted" will get enabled and "min-passphrase-len" set +# to 6. All other users are not allowed to change +# "min-passphrase-len" and "allow-mark-trusted". When "gpgconf +# --apply-defaults" is used for them, "min-passphrase-len" is set to +# 12, "allow-mark-trusted" deleted from the config file and +# "enable-ocsp" is put into the config file of gpgsm. The latter may +# be changed by any user. +#------------------------------------------------------------------- + + +# Allow all users to change the allow-mark-trusted option. +# (This was the default prior to gnupg 2.0.3) +* gpg-agent allow-mark-trusted [change] + + diff --git a/doc/gpg-agent.texi b/doc/gpg-agent.texi index 4119d6601..a886d1534 100644 --- a/doc/gpg-agent.texi +++ b/doc/gpg-agent.texi @@ -336,7 +336,7 @@ been accessed recently. The default are 2 hours (7200 seconds). @item --min-passphrase-len @var{n} @opindex min-passphrase-len -Set the minimal length of a passphrase. When entereing a new passphrase +Set the minimal length of a passphrase. When entering a new passphrase shorter than this value a warning will be displayed. Defaults to 8. @item --pinentry-program @var{filename} diff --git a/doc/tools.texi b/doc/tools.texi index 914a1213f..1e386f521 100644 --- a/doc/tools.texi +++ b/doc/tools.texi @@ -199,6 +199,7 @@ throughout this section. * Listing components:: List all gpgconf components. * Listing options:: List all options of a component. * Changing options:: Changing options of a component. +* Files used by gpgconf:: What files are used by gpgconf. @end menu @manpause @@ -219,8 +220,18 @@ List all options of the component @var{component}. @item --change-options @var{component} Change the options of the component @var{component}. + +@item --apply-defaults +Update all configuration files with values taken from the global +configuration file (usually @file{/etc/gnupg/gpgconf.conf}). + +@item --check-config [@var{filename}] +Run a syntax check ion the global configuration file. If @var{filename} +is given, check that file instead. + @end table + @mansect options The following options may be used: @@ -486,6 +497,11 @@ If this flag is set, a (runtime) default is available. This and the @item no arg desc (64) If this flag is set, and the @code{optional arg} flag is set, then the option has a special meaning if no argument is given. + +@item no change (128) +If this flag is set, gpgconf ignores requests to change the value. GUI +frontends should grey out this option. Note, that manual changes of the +configuration files are still possible. @end table @item level @@ -658,6 +674,20 @@ $ echo 'force:16:' | gpgconf --change-options dirmngr The @code{--runtime} option can influence when the changes take effect. +@mansect files +@node Files used by gpgconf +@subsection Files used by gpgconf + +@table @file + +@item /etc/gnupg/gpg-agent.conf +@cindex gpgconf.conf + If this file exists, it is processed as a global configuration file. + A commented example can be found in the @file{examples} directory of + the distribution. +@end table + + @mansect see also @command{gpg}(1), @command{gpgsm}(1), diff --git a/doc/vuln-announce-2007-multiple-message.txt b/doc/vuln-announce-2007-multiple-message.txt new file mode 100644 index 000000000..dcdb48293 --- /dev/null +++ b/doc/vuln-announce-2007-multiple-message.txt @@ -0,0 +1,145 @@ + Multiple Messages Problem in GnuPG and GPGME + ============================================== + 2007-03-05 + + +Summary +======= + +Gerardo Richarte from Core Security Technologies identified a problem +when using GnuPG in streaming mode. + +The problem is actually a variant of a well known problem in the way +signed material is presented in a MUA. It is possible to insert +additional text before or after a signed (or signed and encrypted) +OpenPGP message and make the user believe that this additional text is +also covered by the signature. The Core Security advisory describes +several variants of the attack; they all boil down to the fact that it +might not be possible to identify which part of a message is actually +signed if gpg is not used correctly. + +[ Please do not send private mail in response to this message. The + mailing list gnupg-devel is the best place to discuss this problem + (please subscribe first so you don't need moderator approval [1]). ] + + +Impact +====== + +All applications using GnuPG without properly using the status +interface to verify signed or signed and encrypted messages. + +All GPGME versions up to and including 1.1.3. + +Starting with version 1.4.7 and 2.0.3, GnuPG implements an additional +and sufficient protection against this common usage problem. + +Detached signatures are in no way affected by this problem. + + +Description +=========== + +When using gpg (or gpg2) in a pipeline or with redirected input and +output additional data may be inserted into a message. This allows to +forge a signed message by prefixing it with arbitrary material. A way +to create such a message is: + + echo "This is my sneaky plaintext message" > foobar.txt + gpg -z0 --output prefix.gpg --store foobar.txt + cat prefix.gpg original-signed-message.gpg > forged.gpg + +Using gpg naively this results in: + + $ gpg <forged.gpg + This is my sneaky plaintext message + Either I'm dead or my watch has stopped. + -- Groucho Marx's last words + gpg: Signature made Mon Feb 26 09:57:04 2007 CET using DSA key ID 68697734 + gpg: Good signature from "Alfa Test (demo key) <[email protected]>" + [...] + +and thus gives the impression that the sneaky message is part of the +signed Groucho quote. The correct way to use gpg with redirection is +by taking care of the status interface: + + $ gpg --status-fd 1 <forged.gpg + [GNUPG:] PLAINTEXT 62 1172479053 foobar.txt + [GNUPG:] PLAINTEXT_LENGTH 36 + This is my sneaky plaintext message + [GNUPG:] PLAINTEXT 62 1172480224 original-signed-message + [GNUPG:] PLAINTEXT_LENGTH 86 + Either I'm dead or my watch has stopped. + -- Groucho Marx's last words + gpg: Signature made Mon Feb 26 09:57:04 2007 CET using DSA key ID 68697734 + [GNUPG:] SIG_ID UncMPBJYgbG/uszJVNKoCAz+hvY 2007-02-26 1172480224 + [GNUPG:] GOODSIG 2D727CC768697734 Alfa Test (demo key) <[email protected]> + gpg: Good signature from "Alfa Test (demo key) <[email protected]>" + [...] + +Here the PLAINTEXT status lines clearly identify the start of a new +message. + +Note, that using gpg on the command line is in almost all cases not +done with redirection but by letting gpg save the the signed message. +In this case gpg will save the message to different files or in case +the file names are identical, prompt the over to overwrite the first +one again. + +Because the problem of identifying the actual signed content when +mixing the signed data and the signature is very common, the long +standing suggestion for all digital signatures is to use a detached +signature. A detached signature allows to clearly identify what is +signed and what is the signature. This is also the reason why +PGP/MIME signed messages are in general to be preferred over the old +style clear signed messages. + + +Solution +======== + +Given that there are many applications in use which are subject to the +described problem, we have decided to change GnuPG so that such forged +OpenPGP messages are detected and the signature verification will +fail. GnuPG 1.4.7 has been released today and is available from the +usual places [2]. If you don't want to update, a minimal patch +against GnuPG 1.4.6 is available at + + ftp://ftp.gnupg.org/gcrypt/gnupg/patches/gnupg-1.4.6-multiple-message.patch + +Many applications are using the library GPGME which implements an easy +way to process OpenPGP messages using gpg. We have updated GPGME to +make it immune against this problem even if an old version of gpg is +being used. GPGME 1.1.4 is available from the usual places [2]. A +patch (against version 1.1.3 or 1.1.2) is available at + + ftp://ftp.gnupg.org/gcrypt/gpgme/patches/gpgme-1.1.3-multiple-message.patch + +Please note that - after applying one of these patches - some +vulnerable applications (mainly MUAs) may fail to handle certain +messages which are composed of several OpenPGP messages. To continue +the support of such messages fixing the application is required as +there is no way for GnuPG to do it. + + +Support +======= + +g10 Code GmbH [3], a Duesseldorf based company owned and headed by +GnuPG's principal author, is currently funding GnuPG development. +Support contracts or other financial backing will greatly help us to +improve the quality of GnuPG. + + +Thanks +====== + +Gerardo Richarte found this problem. David Shaw greatly helped to +analyse and describe the core of the problem. + + + + +[1] See http://lists.gnupg.org/mailman/listinfo/gnupg-devel +[2] See http://www.gnupg.org/download/ +[3] See http://www.gnupg.org/service.html |