Add option commandline_checks_require_admin

May help with scenarios already so broken that bug report 2118 is
actually an issue (Wordpress vuln).

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index 5b735907ed012e7d914ce6f0b44f43eedfb13a38..f33b193eb781f3abcbbe2d99fac7ea030b214bda 100644 (file)
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -13599,6 +13599,7 @@ listed in more than one group.
 .section "Privilege controls" "SECID98"
 .table2
 .row &%admin_groups%&                "groups that are Exim admin users"
+.row &%commandline_checks_require_admin%& "require admin for various checks"
 .row &%deliver_drop_privilege%&      "drop root for delivery processes"
 .row &%local_from_check%&            "insert &'Sender:'& if necessary"
 .row &%local_from_prefix%&           "for testing &'From:'& for local sender"
@@ -14461,6 +14462,14 @@ The CHUNKING extension (RFC3030) will be advertised in the EHLO message to
 these hosts.
 Hosts may use the BDAT command as an alternate to DATA.
 
+.new
+.option commandline_checks_require_admin main boolean &`false`&
+.cindex "restricting access to features"
+This option restricts various basic checking features to require an
+administrative user.
+This affects most of the &%-b*%& options, such as &%-be%&.
+.wen
+
 .option debug_store main boolean &`false`&
 .cindex debugging "memory corruption"
 .cindex memory debugging
@@ -15942,12 +15951,13 @@ different spool directories.
 
 
 .option prod_requires_admin main boolean true
+.cindex "restricting access to features"
 .oindex "&%-M%&"
 .oindex "&%-R%&"
 .oindex "&%-q%&"
 The &%-M%&, &%-R%&, and &%-q%& command-line options require the caller to be an
 admin user unless &%prod_requires_admin%& is set false. See also
-&%queue_list_requires_admin%&.
+&%queue_list_requires_admin%& and &%commandline_checks_require_admin%&.
 
 
 .option qualify_domain main string "see below"
@@ -15986,10 +15996,12 @@ next queue run. See also &%hold_domains%& and &%queue_smtp_domains%&.
 
 
 .option queue_list_requires_admin main boolean true
+.cindex "restricting access to features"
 .oindex "&%-bp%&"
 The &%-bp%& command-line option, which lists the messages that are on the
 queue, requires the caller to be an admin user unless
-&%queue_list_requires_admin%& is set false. See also &%prod_requires_admin%&.
+&%queue_list_requires_admin%& is set false.
+See also &%prod_requires_admin%& and &%commandline_checks_require_admin%&.
 
 
 .option queue_only main boolean false
@@ -20333,11 +20345,15 @@ relative path is then passed to the transport unmodified.
 
 
 .option forbid_blackhole redirect boolean false
+.cindex "restricting access to features"
+.cindex "filter" "locking out certain features"
 If this option is true, the &':blackhole:'& item may not appear in a
 redirection list.
 
 
 .option forbid_exim_filter redirect boolean false
+.cindex "restricting access to features"
+.cindex "filter" "locking out certain features"
 If this option is set true, only Sieve filters are permitted when
 &%allow_filter%& is true.
 
@@ -20345,7 +20361,9 @@ If this option is set true, only Sieve filters are permitted when
 
 
 .option forbid_file redirect boolean false
+.cindex "restricting access to features"
 .cindex "delivery" "to file; forbidding"
+.cindex "filter" "locking out certain features"
 .cindex "Sieve filter" "forbidding delivery to a file"
 .cindex "Sieve filter" "&""keep""& facility; disabling"
 If this option is true, this router may not generate a new address that
@@ -20356,17 +20374,22 @@ locks out the Sieve's &"keep"& facility.
 
 
 .option forbid_filter_dlfunc redirect boolean false
+.cindex "restricting access to features"
 .cindex "filter" "locking out certain features"
 If this option is true, string expansions in Exim filters are not allowed to
 make use of the &%dlfunc%& expansion facility to run dynamically loaded
 functions.
 
 .option forbid_filter_existstest redirect boolean false
+.cindex "restricting access to features"
+.cindex "filter" "locking out certain features"
 .cindex "expansion" "statting a file"
 If this option is true, string expansions in Exim filters are not allowed to
 make use of the &%exists%& condition or the &%stat%& expansion item.
 
 .option forbid_filter_logwrite redirect boolean false
+.cindex "restricting access to features"
+.cindex "filter" "locking out certain features"
 If this option is true, use of the logging facility in Exim filters is not
 permitted. Logging is in any case available only if the filter is being run
 under some unprivileged uid (which is normally the case for ordinary users'
@@ -20374,27 +20397,37 @@ under some unprivileged uid (which is normally the case for ordinary users'
 
 
 .option forbid_filter_lookup redirect boolean false
+.cindex "restricting access to features"
+.cindex "filter" "locking out certain features"
 If this option is true, string expansions in Exim filter files are not allowed
 to make use of &%lookup%& items.
 
 
 .option forbid_filter_perl redirect boolean false
+.cindex "restricting access to features"
+.cindex "filter" "locking out certain features"
 This option has an effect only if Exim is built with embedded Perl support. If
 it is true, string expansions in Exim filter files are not allowed to make use
 of the embedded Perl support.
 
 
 .option forbid_filter_readfile redirect boolean false
+.cindex "restricting access to features"
+.cindex "filter" "locking out certain features"
 If this option is true, string expansions in Exim filter files are not allowed
 to make use of &%readfile%& items.
 
 
 .option forbid_filter_readsocket redirect boolean false
+.cindex "restricting access to features"
+.cindex "filter" "locking out certain features"
 If this option is true, string expansions in Exim filter files are not allowed
 to make use of &%readsocket%& items.
 
 
 .option forbid_filter_reply redirect boolean false
+.cindex "restricting access to features"
+.cindex "filter" "locking out certain features"
 If this option is true, this router may not generate an automatic reply
 message. Automatic replies can be generated only from Exim or Sieve filter
 files, not from traditional forward files. This option is forced to be true if
@@ -20402,11 +20435,15 @@ files, not from traditional forward files. This option is forced to be true if
 
 
 .option forbid_filter_run redirect boolean false
+.cindex "restricting access to features"
+.cindex "filter" "locking out certain features"
 If this option is true, string expansions in Exim filter files are not allowed
 to make use of &%run%& items.
 
 
 .option forbid_include redirect boolean false
+.cindex "restricting access to features"
+.cindex "filter" "locking out certain features"
 If this option is true, items of the form
 .code
 :include:<path name>
@@ -20415,6 +20452,8 @@ are not permitted in non-filter redirection lists.
 
 
 .option forbid_pipe redirect boolean false
+.cindex "restricting access to features"
+.cindex "filter" "locking out certain features"
 .cindex "delivery" "to pipe; forbidding"
 If this option is true, this router may not generate a new address which
 specifies delivery to a pipe, either from an Exim filter or from a conventional
@@ -20422,6 +20461,8 @@ forward file. This option is forced to be true if &%one_time%& is set.
 
 
 .option forbid_sieve_filter redirect boolean false
+.cindex "restricting access to features"
+.cindex "filter" "locking out certain features"
 If this option is set true, only Exim filters are permitted when
 &%allow_filter%& is true.
 
@@ -37957,6 +37998,13 @@ the contents of files on the spool via the Exim monitor (which runs
 unprivileged), Exim must be built to allow group read access to its spool
 files.
 
+.new
+By default, regular users are trusted to perform basic testing and
+introspection commands, as themselves.  This setting can be tightened by
+setting the &%commandline_checks_require_admin%& option.
+This affects most of the checking options,
+such as &%-be%& and anything else &%-b*%&.
+.wen
 
 
 .section "Spool files" "SECID275"

diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog
index 2078b352189c8dccabdd1a62b285cc5362a1074e..4bc5235ecdbfe4ac1f215192bab4fc6dc4988b08 100644 (file)
--- a/doc/doc-txt/ChangeLog
+++ b/doc/doc-txt/ChangeLog
@@ -78,6 +78,14 @@ JH/12 Fix check on SMTP command input synchronisation.  Previously there were
       or prompt from Exim (running as a server), due to that code's lack of
       awareness of the SMTP input buferring.
 
+PP/04 Add commandline_checks_require_admin option.
+      Exim drops privileges sanely, various checks such as -be aren't a
+      security problem, as long as you trust local users with access to their
+      own account.  When invoked by services which pass untrusted data to
+      Exim, this might be an issue.  Set this option in main configuration
+      AND make fixes to the calling application, such as using `--` to stop
+      processing options.
+
 
 Exim version 4.89
 -----------------

diff --git a/doc/doc-txt/NewStuff b/doc/doc-txt/NewStuff
index cb2346f693f7339cbf562528d73e34619556e237..5fd7fbb29a588d6f743afb76fe2c5f59cebf15fc 100644 (file)
--- a/doc/doc-txt/NewStuff
+++ b/doc/doc-txt/NewStuff
@@ -35,6 +35,9 @@ Version 4.90
     received using the ESMTP CHUNKING option, and when a new main-section
     option "spool_wireformat" (false by default) is set.
 
+ 8. New main configuration option "commandline_checks_require_admin" to
+    restrict who can use various introspection options.
+
 
 Version 4.89
 ------------

diff --git a/doc/doc-txt/OptionLists.txt b/doc/doc-txt/OptionLists.txt
index 95d321e5c9c3f3ace8b3c3167f6facc80e3102a4..5728643a8bb01bce129cd00bb66d7a8fc0ce2d97 100644 (file)
--- a/doc/doc-txt/OptionLists.txt
+++ b/doc/doc-txt/OptionLists.txt
@@ -137,6 +137,7 @@ command                              string*         unset         lmtp
 command_group                        string          unset         queryprogram      4.00
 command_timeout                      time            5m            smtp
 command_user                         string          unset         queryprogram      4.00
+commandline_checks_require_admin     boolean         false         main              4.90
 condition                            string*         unset         routers           4.00
 connect_timeout                      time            0s            smtp              1.60
 connection_max_messages              integer         500           smtp              4.00 replaces batch_max

diff --git a/src/src/exim.c b/src/src/exim.c
index dcc84e3d5cad3af1ecd47c171f9d2299cb642d8e..67583e5842a4a019801030389bcfcffbe0a909a7 100644 (file)
--- a/src/src/exim.c
+++ b/src/src/exim.c
@@ -3868,6 +3868,14 @@ else
           trusted_caller = TRUE;
   }
 
+/* At this point, we know if the user is privileged and some command-line
+options become possibly imperssible, depending upon the configuration file. */
+
+if (checking && commandline_checks_require_admin && !admin_user) {
+  fprintf(stderr, "exim: those command-line flags are set to require admin\n");
+  exit(EXIT_FAILURE);
+}
+
 /* Handle the decoding of logging options. */
 
 decode_bits(log_selector, log_selector_size, log_notall,

diff --git a/src/src/globals.c b/src/src/globals.c
index 46db4f373e7bc637a4158a9c64ae54b3d1fc058e..9b455c9db65170ccaeb65edf9132366d3dc0a595 100644 (file)
--- a/src/src/globals.c
+++ b/src/src/globals.c
@@ -511,6 +511,7 @@ uschar *client_authenticated_id = NULL;
 uschar *client_authenticated_sender = NULL;
 int     clmacro_count          = 0;
 uschar *clmacros[MAX_CLMACROS];
+BOOL    commandline_checks_require_admin = FALSE;
 BOOL    config_changed         = FALSE;
 FILE   *config_file            = NULL;
 const uschar *config_filename  = NULL;

diff --git a/src/src/globals.h b/src/src/globals.h
index 63c9c29c774cb48461a907be56e975ff8771502e..056f1c213c8ed60f229e1c6c0aed999ffa914651 100644 (file)
--- a/src/src/globals.h
+++ b/src/src/globals.h
@@ -282,6 +282,7 @@ extern uschar *client_authenticated_id;     /* "login" name used for SMTP AUTH *
 extern uschar *client_authenticated_sender; /* AUTH option to SMTP MAIL FROM (not yet used) */
 extern int     clmacro_count;          /* Number of command line macros */
 extern uschar *clmacros[];             /* Copy of them, for re-exec */
+extern BOOL    commandline_checks_require_admin; /* belt and braces for insecure setups */
 extern int     connection_max_messages;/* Max down one SMTP connection */
 extern BOOL    config_changed;         /* True if -C used */
 extern FILE   *config_file;            /* Configuration file */

diff --git a/src/src/readconf.c b/src/src/readconf.c
index f43a3d1633abcd3ba2e590de9d4fa7f29316f1c8..95abaf5be8d25bf5513ceb10dd2fe1930f28b9ac 100644 (file)
--- a/src/src/readconf.c
+++ b/src/src/readconf.c
@@ -217,6 +217,7 @@ static optionlist optionlist_config[] = {
   { "check_spool_inodes",       opt_int,         &check_spool_inodes },
   { "check_spool_space",        opt_Kint,        &check_spool_space },
   { "chunking_advertise_hosts", opt_stringptr,  &chunking_advertise_hosts },
+  { "commandline_checks_require_admin", opt_bool,&commandline_checks_require_admin },
   { "daemon_smtp_port",         opt_stringptr|opt_hidden, &daemon_smtp_port },
   { "daemon_smtp_ports",        opt_stringptr,   &daemon_smtp_port },
   { "daemon_startup_retries",   opt_int,         &daemon_startup_retries },