diff options
Diffstat (limited to 'system/polkit/CVE-2015-4625.patch')
| -rw-r--r-- | system/polkit/CVE-2015-4625.patch | 1008 |
1 files changed, 1008 insertions, 0 deletions
diff --git a/system/polkit/CVE-2015-4625.patch b/system/polkit/CVE-2015-4625.patch new file mode 100644 index 000000000..4a43fb433 --- /dev/null +++ b/system/polkit/CVE-2015-4625.patch @@ -0,0 +1,1008 @@ +From ea544ffc18405237ccd95d28d7f45afef49aca17 Mon Sep 17 00:00:00 2001 +From: Colin Walters <walters@redhat.com> +Date: Thu, 4 Jun 2015 12:15:18 -0400 +Subject: CVE-2015-4625: Use unpredictable cookie values, keep them secret +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +Tavis noted that it'd be possible with a 32 bit counter for someone to +cause the cookie to wrap by creating Authentication requests in a +loop. + +Something important to note here is that wrapping of signed integers +is undefined behavior in C, so we definitely want to fix that. All +counter integers used in this patch are unsigned. + +See the comment above `authentication_agent_generate_cookie` for +details, but basically we're now using a cookie of the form: + +``` + <agent serial> - <agent random id> - <session serial> - <session +random id> +``` + +Which has multiple 64 bit counters, plus unpredictable random 128 bit +integer ids (effectively UUIDs, but we're not calling them that +because we don't need to be globally unique. + +We further ensure that the cookies are not visible to other processes +by changing the setuid helper to accept them over standard input. This +means that an attacker would have to guess both ids. + +In any case, the security hole here is better fixed with the other +change to bind user id (uid) of the agent with cookie lookups, making +cookie guessing worthless. + +Nevertheless, I think it's worth doing this change too, for defense in +depth. + +Bug: https://bugs.freedesktop.org/show_bug.cgi?id=90832 +CVE: CVE-2015-4625 +Reported-by: Tavis Ormandy <taviso@google.com> +Reviewed-by: Miloslav Trmač <mitr@redhat.com> +Signed-off-by: Colin Walters <walters@redhat.com> + +diff --git a/src/polkitagent/polkitagenthelper-pam.c b/src/polkitagent/polkitagenthelper-pam.c +index 937386e..19062aa 100644 +--- a/src/polkitagent/polkitagenthelper-pam.c ++++ b/src/polkitagent/polkitagenthelper-pam.c +@@ -65,7 +65,7 @@ main (int argc, char *argv[]) + { + int rc; + const char *user_to_auth; +- const char *cookie; ++ char *cookie = NULL; + struct pam_conv pam_conversation; + pam_handle_t *pam_h; + const void *authed_user; +@@ -97,7 +97,7 @@ main (int argc, char *argv[]) + openlog ("polkit-agent-helper-1", LOG_CONS | LOG_PID, LOG_AUTHPRIV); + + /* check for correct invocation */ +- if (argc != 3) ++ if (!(argc == 2 || argc == 3)) + { + syslog (LOG_NOTICE, "inappropriate use of helper, wrong number of arguments [uid=%d]", getuid ()); + fprintf (stderr, "polkit-agent-helper-1: wrong number of arguments. This incident has been logged.\n"); +@@ -105,7 +105,10 @@ main (int argc, char *argv[]) + } + + user_to_auth = argv[1]; +- cookie = argv[2]; ++ ++ cookie = read_cookie (argc, argv); ++ if (!cookie) ++ goto error; + + if (getuid () != 0) + { +@@ -203,6 +206,8 @@ main (int argc, char *argv[]) + goto error; + } + ++ free (cookie); ++ + #ifdef PAH_DEBUG + fprintf (stderr, "polkit-agent-helper-1: successfully sent D-Bus message to PolicyKit daemon\n"); + #endif /* PAH_DEBUG */ +@@ -212,6 +217,7 @@ main (int argc, char *argv[]) + return 0; + + error: ++ free (cookie); + if (pam_h != NULL) + pam_end (pam_h, rc); + +diff --git a/src/polkitagent/polkitagenthelper-shadow.c b/src/polkitagent/polkitagenthelper-shadow.c +index a4f73ac..e877915 100644 +--- a/src/polkitagent/polkitagenthelper-shadow.c ++++ b/src/polkitagent/polkitagenthelper-shadow.c +@@ -46,7 +46,7 @@ main (int argc, char *argv[]) + { + struct spwd *shadow; + const char *user_to_auth; +- const char *cookie; ++ char *cookie = NULL; + time_t now; + + /* clear the entire environment to avoid attacks with +@@ -67,7 +67,7 @@ main (int argc, char *argv[]) + openlog ("polkit-agent-helper-1", LOG_CONS | LOG_PID, LOG_AUTHPRIV); + + /* check for correct invocation */ +- if (argc != 3) ++ if (!(argc == 2 || argc == 3)) + { + syslog (LOG_NOTICE, "inappropriate use of helper, wrong number of arguments [uid=%d]", getuid ()); + fprintf (stderr, "polkit-agent-helper-1: wrong number of arguments. This incident has been logged.\n"); +@@ -86,7 +86,10 @@ main (int argc, char *argv[]) + } + + user_to_auth = argv[1]; +- cookie = argv[2]; ++ ++ cookie = read_cookie (argc, argv); ++ if (!cookie) ++ goto error; + + #ifdef PAH_DEBUG + fprintf (stderr, "polkit-agent-helper-1: user to auth is '%s'.\n", user_to_auth); +@@ -153,6 +156,8 @@ main (int argc, char *argv[]) + goto error; + } + ++ free (cookie); ++ + #ifdef PAH_DEBUG + fprintf (stderr, "polkit-agent-helper-1: successfully sent D-Bus message to PolicyKit daemon\n"); + #endif /* PAH_DEBUG */ +@@ -162,6 +167,7 @@ main (int argc, char *argv[]) + return 0; + + error: ++ free (cookie); + fprintf (stdout, "FAILURE\n"); + flush_and_wait (); + return 1; +diff --git a/src/polkitagent/polkitagenthelperprivate.c b/src/polkitagent/polkitagenthelperprivate.c +index cfa77fc..e23f9f5 100644 +--- a/src/polkitagent/polkitagenthelperprivate.c ++++ b/src/polkitagent/polkitagenthelperprivate.c +@@ -23,6 +23,7 @@ + #include "config.h" + #include "polkitagenthelperprivate.h" + #include <stdio.h> ++#include <string.h> + #include <stdlib.h> + #include <unistd.h> + +@@ -45,6 +46,38 @@ _polkit_clearenv (void) + #endif + + ++char * ++read_cookie (int argc, char **argv) ++{ ++ /* As part of CVE-2015-4625, we started passing the cookie ++ * on standard input, to ensure it's not visible to other ++ * processes. However, to ensure that things continue ++ * to work if the setuid binary is upgraded while old ++ * agents are still running (this will be common with ++ * package managers), we support both modes. ++ */ ++ if (argc == 3) ++ return strdup (argv[2]); ++ else ++ { ++ char *ret = NULL; ++ size_t n = 0; ++ ssize_t r = getline (&ret, &n, stdin); ++ if (r == -1) ++ { ++ if (!feof (stdin)) ++ perror ("getline"); ++ free (ret); ++ return NULL; ++ } ++ else ++ { ++ g_strchomp (ret); ++ return ret; ++ } ++ } ++} ++ + gboolean + send_dbus_message (const char *cookie, const char *user) + { +diff --git a/src/polkitagent/polkitagenthelperprivate.h b/src/polkitagent/polkitagenthelperprivate.h +index aeca2c7..547fdcc 100644 +--- a/src/polkitagent/polkitagenthelperprivate.h ++++ b/src/polkitagent/polkitagenthelperprivate.h +@@ -38,6 +38,8 @@ + + int _polkit_clearenv (void); + ++char *read_cookie (int argc, char **argv); ++ + gboolean send_dbus_message (const char *cookie, const char *user); + + void flush_and_wait (); +diff --git a/src/polkitagent/polkitagentsession.c b/src/polkitagent/polkitagentsession.c +index f014773..8b93ad0 100644 +--- a/src/polkitagent/polkitagentsession.c ++++ b/src/polkitagent/polkitagentsession.c +@@ -55,6 +55,7 @@ + #include <stdio.h> + #include <sys/types.h> + #include <sys/wait.h> ++#include <gio/gunixoutputstream.h> + #include <pwd.h> + + #include "polkitagentmarshal.h" +@@ -88,7 +89,7 @@ struct _PolkitAgentSession + gchar *cookie; + PolkitIdentity *identity; + +- int child_stdin; ++ GOutputStream *child_stdin; + int child_stdout; + GPid child_pid; + +@@ -129,7 +130,6 @@ G_DEFINE_TYPE (PolkitAgentSession, polkit_agent_session, G_TYPE_OBJECT); + static void + polkit_agent_session_init (PolkitAgentSession *session) + { +- session->child_stdin = -1; + session->child_stdout = -1; + } + +@@ -395,11 +395,7 @@ kill_helper (PolkitAgentSession *session) + session->child_stdout = -1; + } + +- if (session->child_stdin != -1) +- { +- g_warn_if_fail (close (session->child_stdin) == 0); +- session->child_stdin = -1; +- } ++ g_clear_object (&session->child_stdin); + + session->helper_is_running = FALSE; + +@@ -545,9 +541,9 @@ polkit_agent_session_response (PolkitAgentSession *session, + + add_newline = (response[response_len] != '\n'); + +- write (session->child_stdin, response, response_len); ++ (void) g_output_stream_write_all (session->child_stdin, response, response_len, NULL, NULL, NULL); + if (add_newline) +- write (session->child_stdin, newline, 1); ++ (void) g_output_stream_write_all (session->child_stdin, newline, 1, NULL, NULL, NULL); + } + + /** +@@ -567,8 +563,9 @@ polkit_agent_session_initiate (PolkitAgentSession *session) + { + uid_t uid; + GError *error; +- gchar *helper_argv[4]; ++ gchar *helper_argv[3]; + struct passwd *passwd; ++ int stdin_fd = -1; + + g_return_if_fail (POLKIT_AGENT_IS_SESSION (session)); + +@@ -600,10 +597,8 @@ polkit_agent_session_initiate (PolkitAgentSession *session) + + helper_argv[0] = PACKAGE_PREFIX "/lib/polkit-1/polkit-agent-helper-1"; + helper_argv[1] = passwd->pw_name; +- helper_argv[2] = session->cookie; +- helper_argv[3] = NULL; ++ helper_argv[2] = NULL; + +- session->child_stdin = -1; + session->child_stdout = -1; + + error = NULL; +@@ -615,7 +610,7 @@ polkit_agent_session_initiate (PolkitAgentSession *session) + NULL, + NULL, + &session->child_pid, +- &session->child_stdin, ++ &stdin_fd, + &session->child_stdout, + NULL, + &error)) +@@ -628,6 +623,13 @@ polkit_agent_session_initiate (PolkitAgentSession *session) + if (G_UNLIKELY (_show_debug ())) + g_print ("PolkitAgentSession: spawned helper with pid %d\n", (gint) session->child_pid); + ++ session->child_stdin = (GOutputStream*)g_unix_output_stream_new (stdin_fd, TRUE); ++ ++ /* Write the cookie on stdin so it can't be seen by other processes */ ++ (void) g_output_stream_write_all (session->child_stdin, session->cookie, strlen (session->cookie), ++ NULL, NULL, NULL); ++ (void) g_output_stream_write_all (session->child_stdin, "\n", 1, NULL, NULL, NULL); ++ + session->child_stdout_channel = g_io_channel_unix_new (session->child_stdout); + session->child_stdout_watch_source = g_io_create_watch (session->child_stdout_channel, + G_IO_IN | G_IO_ERR | G_IO_HUP); +diff --git a/src/polkitbackend/polkitbackendinteractiveauthority.c b/src/polkitbackend/polkitbackendinteractiveauthority.c +index 3f339e9..15adc6a 100644 +--- a/src/polkitbackend/polkitbackendinteractiveauthority.c ++++ b/src/polkitbackend/polkitbackendinteractiveauthority.c +@@ -214,6 +214,8 @@ typedef struct + + GDBusConnection *system_bus_connection; + guint name_owner_changed_signal_id; ++ ++ guint64 agent_serial; + } PolkitBackendInteractiveAuthorityPrivate; + + /* ---------------------------------------------------------------------------------------------------- */ +@@ -439,11 +441,15 @@ struct AuthenticationAgent + volatile gint ref_count; + + PolkitSubject *scope; ++ guint64 serial; + + gchar *locale; + GVariant *registration_options; + gchar *object_path; + gchar *unique_system_bus_name; ++ GRand *cookie_pool; ++ gchar *cookie_prefix; ++ guint64 cookie_serial; + + GDBusProxy *proxy; + +@@ -1427,9 +1433,54 @@ authentication_session_cancelled_cb (GCancellable *cancellable, + authentication_session_cancel (session); + } + ++/* We're not calling this a UUID, but it's basically ++ * the same thing, just not formatted that way because: ++ * ++ * - I'm too lazy to do it ++ * - If we did, people might think it was actually ++ * generated from /dev/random, which we're not doing ++ * because this value doesn't actually need to be ++ * globally unique. ++ */ ++static void ++append_rand_u128_str (GString *buf, ++ GRand *pool) ++{ ++ g_string_append_printf (buf, "%08x%08x%08x%08x", ++ g_rand_int (pool), ++ g_rand_int (pool), ++ g_rand_int (pool), ++ g_rand_int (pool)); ++} ++ ++/* A value that should be unique to the (AuthenticationAgent, AuthenticationSession) ++ * pair, and not guessable by other agents. ++ * ++ * <agent serial> - <agent uuid> - <session serial> - <session uuid> ++ * ++ * See http://lists.freedesktop.org/archives/polkit-devel/2015-June/000425.html ++ * ++ */ ++static gchar * ++authentication_agent_generate_cookie (AuthenticationAgent *agent) ++{ ++ GString *buf = g_string_new (""); ++ ++ g_string_append (buf, agent->cookie_prefix); ++ ++ g_string_append_c (buf, '-'); ++ agent->cookie_serial++; ++ g_string_append_printf (buf, "%" G_GUINT64_FORMAT, ++ agent->cookie_serial); ++ g_string_append_c (buf, '-'); ++ append_rand_u128_str (buf, agent->cookie_pool); ++ ++ return g_string_free (buf, FALSE); ++} ++ ++ + static AuthenticationSession * + authentication_session_new (AuthenticationAgent *agent, +- const gchar *cookie, + PolkitSubject *subject, + PolkitIdentity *user_of_subject, + PolkitSubject *caller, +@@ -1447,7 +1498,7 @@ authentication_session_new (AuthenticationAgent *agent, + + session = g_new0 (AuthenticationSession, 1); + session->agent = authentication_agent_ref (agent); +- session->cookie = g_strdup (cookie); ++ session->cookie = authentication_agent_generate_cookie (agent); + session->subject = g_object_ref (subject); + session->user_of_subject = g_object_ref (user_of_subject); + session->caller = g_object_ref (caller); +@@ -1496,16 +1547,6 @@ authentication_session_free (AuthenticationSession *session) + g_free (session); + } + +-static gchar * +-authentication_agent_new_cookie (AuthenticationAgent *agent) +-{ +- static gint counter = 0; +- +- /* TODO: use a more random-looking cookie */ +- +- return g_strdup_printf ("cookie%d", counter++); +-} +- + static PolkitSubject * + authentication_agent_get_scope (AuthenticationAgent *agent) + { +@@ -1553,12 +1594,15 @@ authentication_agent_unref (AuthenticationAgent *agent) + g_free (agent->unique_system_bus_name); + if (agent->registration_options != NULL) + g_variant_unref (agent->registration_options); ++ g_rand_free (agent->cookie_pool); ++ g_free (agent->cookie_prefix); + g_free (agent); + } + } + + static AuthenticationAgent * +-authentication_agent_new (PolkitSubject *scope, ++authentication_agent_new (guint64 serial, ++ PolkitSubject *scope, + const gchar *unique_system_bus_name, + const gchar *locale, + const gchar *object_path, +@@ -1592,6 +1636,7 @@ authentication_agent_new (PolkitSubject *scope, + + agent = g_new0 (AuthenticationAgent, 1); + agent->ref_count = 1; ++ agent->serial = serial; + agent->scope = g_object_ref (scope); + agent->object_path = g_strdup (object_path); + agent->unique_system_bus_name = g_strdup (unique_system_bus_name); +@@ -1599,6 +1644,25 @@ authentication_agent_new (PolkitSubject *scope, + agent->registration_options = registration_options != NULL ? g_variant_ref (registration_options) : NULL; + agent->proxy = proxy; + ++ { ++ GString *cookie_prefix = g_string_new (""); ++ GRand *agent_private_rand = g_rand_new (); ++ ++ g_string_append_printf (cookie_prefix, "%" G_GUINT64_FORMAT "-", agent->serial); ++ ++ /* Use a uniquely seeded PRNG to get a prefix cookie for this agent, ++ * whose sequence will not correlate with the per-authentication session ++ * cookies. ++ */ ++ append_rand_u128_str (cookie_prefix, agent_private_rand); ++ g_rand_free (agent_private_rand); ++ ++ agent->cookie_prefix = g_string_free (cookie_prefix, FALSE); ++ ++ /* And a newly seeded pool for per-session cookies */ ++ agent->cookie_pool = g_rand_new (); ++ } ++ + return agent; + } + +@@ -2193,7 +2257,6 @@ authentication_agent_initiate_challenge (AuthenticationAgent *agent, + { + PolkitBackendInteractiveAuthorityPrivate *priv = POLKIT_BACKEND_INTERACTIVE_AUTHORITY_GET_PRIVATE (authority); + AuthenticationSession *session; +- gchar *cookie; + GList *l; + GList *identities; + gchar *localized_message; +@@ -2215,8 +2278,6 @@ authentication_agent_initiate_challenge (AuthenticationAgent *agent, + &localized_icon_name, + &localized_details); + +- cookie = authentication_agent_new_cookie (agent); +- + identities = NULL; + + /* select admin user if required by the implicit authorization */ +@@ -2279,7 +2340,6 @@ authentication_agent_initiate_challenge (AuthenticationAgent *agent, + user_identities = g_list_prepend (NULL, polkit_unix_user_new (0)); + + session = authentication_session_new (agent, +- cookie, + subject, + user_of_subject, + caller, +@@ -2335,7 +2395,6 @@ authentication_agent_initiate_challenge (AuthenticationAgent *agent, + g_list_free_full (user_identities, g_object_unref); + g_list_foreach (identities, (GFunc) g_object_unref, NULL); + g_list_free (identities); +- g_free (cookie); + + g_free (localized_message); + g_free (localized_icon_name); +@@ -2482,7 +2541,9 @@ polkit_backend_interactive_authority_register_authentication_agent (PolkitBacken + goto out; + } + +- agent = authentication_agent_new (subject, ++ priv->agent_serial++; ++ agent = authentication_agent_new (priv->agent_serial, ++ subject, + polkit_system_bus_name_get_name (POLKIT_SYSTEM_BUS_NAME (caller)), + locale, + object_path, +-- +cgit v0.10.2 + +From 493aa5dc1d278ab9097110c1262f5229bbaf1766 Mon Sep 17 00:00:00 2001 +From: Colin Walters <walters@redhat.com> +Date: Wed, 17 Jun 2015 13:07:02 -0400 +Subject: CVE-2015-4625: Bind use of cookies to specific uids +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +http://lists.freedesktop.org/archives/polkit-devel/2015-June/000425.html + +The "cookie" value that Polkit hands out is global to all polkit +users. And when `AuthenticationAgentResponse` is invoked, we +previously only received the cookie and *target* identity, and +attempted to find an agent from that. + +The problem is that the current cookie is just an integer +counter, and if it overflowed, it would be possible for +an successful authorization in one session to trigger a response +in another session. + +The overflow and ability to guess the cookie were fixed by the +previous patch. + +This patch is conceptually further hardening on top of that. Polkit +currently treats uids as equivalent from a security domain +perspective; there is no support for +SELinux/AppArmor/etc. differentiation. + +We can retrieve the uid from `getuid()` in the setuid helper, which +allows us to ensure the uid invoking `AuthenticationAgentResponse2` +matches that of the agent. + +Then the authority only looks at authentication sessions matching the +cookie that were created by a matching uid, thus removing the ability +for different uids to interfere with each other entirely. + +Several fixes to this patch were contributed by: +Miloslav Trmač <mitr@redhat.com> + +Bug: https://bugs.freedesktop.org/show_bug.cgi?id=90837 +CVE: CVE-2015-4625 +Reported-by: Tavis Ormandy <taviso@google.com> +Reviewed-by: Miloslav Trmač <mitr@redhat.com> +Signed-off-by: Colin Walters <walters@redhat.com> + +diff --git a/data/org.freedesktop.PolicyKit1.AuthenticationAgent.xml b/data/org.freedesktop.PolicyKit1.AuthenticationAgent.xml +index 3b519c2..5beef7d 100644 +--- a/data/org.freedesktop.PolicyKit1.AuthenticationAgent.xml ++++ b/data/org.freedesktop.PolicyKit1.AuthenticationAgent.xml +@@ -8,7 +8,19 @@ + <annotation name="org.gtk.EggDBus.DocString" value="<para>This D-Bus interface is used for communication between the system-wide PolicyKit daemon and one or more authentication agents each running in a user session.</para><para>An authentication agent must implement this interface and register (passing the object path of the object implementing the interface) using the org.freedesktop.PolicyKit1.Authority.RegisterAuthenticationAgent() and org.freedesktop.PolicyKit1.Authority.UnregisterAuthenticationAgent() methods on the #org.freedesktop.PolicyKit1.Authority interface of the PolicyKit daemon.</para>"/> + + <method name="BeginAuthentication"> +- <annotation name="org.gtk.EggDBus.DocString" value="<para>Called by the PolicyKit daemon when the authentication agent needs the user to authenticate as one of the identities in @identities for the action with the identifier @action_id.</para><para>Upon succesful authentication, the authentication agent must invoke the org.freedesktop.PolicyKit1.Authority.AuthenticationAgentResponse() method on the #org.freedesktop.PolicyKit1.Authority interface of the PolicyKit daemon before returning.</para><para>If the user dismisses the authentication dialog, the authentication agent should return an error.</para>"/> ++ <annotation name="org.gtk.EggDBus.DocString" value="<para>Called ++ by the PolicyKit daemon when the authentication agent needs the ++ user to authenticate as one of the identities in @identities for ++ the action with the identifier @action_id.</para><para>This ++ authentication is normally achieved via the ++ polkit_agent_session_response() API, which invokes a private ++ setuid helper process to verify the authentication. When ++ successful, it calls the ++ org.freedesktop.PolicyKit1.Authority.AuthenticationAgentResponse2() ++ method on the #org.freedesktop.PolicyKit1.Authority interface of ++ the PolicyKit daemon before returning. If the user dismisses the ++ authentication dialog, the authentication agent should call ++ polkit_agent_session_cancel().</para>"/> + + <arg name="action_id" direction="in" type="s"> + <annotation name="org.gtk.EggDBus.DocString" value="The identifier for the action that the user is authentication for."/> +diff --git a/data/org.freedesktop.PolicyKit1.Authority.xml b/data/org.freedesktop.PolicyKit1.Authority.xml +index fbfb9cd..f9021ee 100644 +--- a/data/org.freedesktop.PolicyKit1.Authority.xml ++++ b/data/org.freedesktop.PolicyKit1.Authority.xml +@@ -313,7 +313,29 @@ + </method> + + <method name="AuthenticationAgentResponse"> +- <annotation name="org.gtk.EggDBus.DocString" value="Method for authentication agents to invoke on successful authentication. This method will fail unless a sufficiently privileged caller invokes it."/> ++ <annotation name="org.gtk.EggDBus.DocString" value="Method for authentication agents to invoke on successful ++authentication, intended only for use by a privileged helper process ++internal to polkit."/> ++ ++ <arg name="cookie" direction="in" type="s"> ++ <annotation name="org.gtk.EggDBus.DocString" value="The cookie identifying the authentication request that was passed to the authentication agent."/> ++ </arg> ++ ++ <arg name="identity" direction="in" type="(sa{sv})"> ++ <annotation name="org.gtk.EggDBus.Type" value="Identity"/> ++ <annotation name="org.gtk.EggDBus.DocString" value="A #Identity struct describing what identity was authenticated."/> ++ </arg> ++ </method> ++ ++ <method name="AuthenticationAgentResponse2"> ++ <annotation name="org.gtk.EggDBus.DocString" value="Method for authentication agents to invoke on successful ++authentication, intended only for use by a privileged helper process ++internal to polkit. Note this method was added in 0.114, and should be preferred over AuthenticationAgentResponse ++as it fixes a security issue."/> ++ ++ <arg name="uid" direction="in" type="u"> ++ <annotation name="org.gtk.EggDBus.DocString" value="The real uid of the agent. Normally set by the setuid helper program."/> ++ </arg> + + <arg name="cookie" direction="in" type="s"> + <annotation name="org.gtk.EggDBus.DocString" value="The cookie identifying the authentication request that was passed to the authentication agent."/> +diff --git a/docs/polkit/docbook-interface-org.freedesktop.PolicyKit1.Authority.xml b/docs/polkit/docbook-interface-org.freedesktop.PolicyKit1.Authority.xml +index 6525e25..e66bf53 100644 +--- a/docs/polkit/docbook-interface-org.freedesktop.PolicyKit1.Authority.xml ++++ b/docs/polkit/docbook-interface-org.freedesktop.PolicyKit1.Authority.xml +@@ -42,6 +42,8 @@ Structure <link linkend="eggdbus-struct-TemporaryAuthorization">TemporaryAuth + IN String object_path) + <link linkend="eggdbus-method-org.freedesktop.PolicyKit1.Authority.AuthenticationAgentResponse">AuthenticationAgentResponse</link> (IN String cookie, + IN <link linkend="eggdbus-struct-Identity">Identity</link> identity) ++<link linkend="eggdbus-method-org.freedesktop.PolicyKit1.Authority.AuthenticationAgentResponse">AuthenticationAgentResponse2</link> (IN uint32 uid, IN String cookie, ++ IN <link linkend="eggdbus-struct-Identity">Identity</link> identity) + <link linkend="eggdbus-method-org.freedesktop.PolicyKit1.Authority.EnumerateTemporaryAuthorizations">EnumerateTemporaryAuthorizations</link> (IN <link linkend="eggdbus-struct-Subject">Subject</link> subject, + OUT Array<<link linkend="eggdbus-struct-TemporaryAuthorization">TemporaryAuthorization</link>> temporary_authorizations) + <link linkend="eggdbus-method-org.freedesktop.PolicyKit1.Authority.RevokeTemporaryAuthorizations">RevokeTemporaryAuthorizations</link> (IN <link linkend="eggdbus-struct-Subject">Subject</link> subject) +@@ -777,10 +779,52 @@ AuthenticationAgentResponse (IN String cookie, + IN <link linkend="eggdbus-struct-Identity">Identity</link> identity) + </programlisting> + <para> +-Method for authentication agents to invoke on successful authentication. This method will fail unless a sufficiently privileged caller invokes it. ++Method for authentication agents to invoke on successful ++authentication, intended only for use by a privileged helper process ++internal to polkit. Deprecated in favor of AuthenticationAgentResponse2. ++ </para> ++<variablelist role="params"> ++ <varlistentry> ++ <term><literal>IN String <parameter>cookie</parameter></literal>:</term> ++ <listitem> ++ <para> ++The cookie identifying the authentication request that was passed to the authentication agent. ++ </para> ++ </listitem> ++ </varlistentry> ++ <varlistentry> ++ <term><literal>IN <link linkend="eggdbus-struct-Identity">Identity</link> <parameter>identity</parameter></literal>:</term> ++ <listitem> ++ <para> ++A <link linkend="eggdbus-struct-Identity">Identity</link> struct describing what identity was authenticated. ++ </para> ++ </listitem> ++ </varlistentry> ++</variablelist> ++ </refsect2> ++ <refsect2 role="function" id="eggdbus-method-org.freedesktop.PolicyKit1.Authority.AuthenticationAgentResponse2"> ++ <title>AuthenticationAgentResponse2 ()</title> ++ <programlisting> ++AuthenticationAgentResponse2 (IN uint32 uid, ++ IN String cookie, ++ IN <link linkend="eggdbus-struct-Identity">Identity</link> identity) ++ </programlisting> ++ <para> ++Method for authentication agents to invoke on successful ++authentication, intended only for use by a privileged helper process ++internal to polkit. Note this method was introduced in 0.114 to fix a security issue. + </para> + <variablelist role="params"> + <varlistentry> ++ <term><literal>IN uint32 <parameter>uid</parameter></literal>:</term> ++ <listitem> ++ <para> ++The user id of the agent; normally this is the owner of the parent pid ++of the process that invoked the internal setuid helper. ++ </para> ++ </listitem> ++ </varlistentry> ++ <varlistentry> + <term><literal>IN String <parameter>cookie</parameter></literal>:</term> + <listitem> + <para> +diff --git a/docs/polkit/overview.xml b/docs/polkit/overview.xml +index 150a7bc..176d2ea 100644 +--- a/docs/polkit/overview.xml ++++ b/docs/polkit/overview.xml +@@ -314,16 +314,18 @@ + <para> + Authentication agents are provided by desktop environments. When + an user session starts, the agent registers with the polkit +- Authority using +- the <link linkend="eggdbus-method-org.freedesktop.PolicyKit1.Authority.RegisterAuthenticationAgent">RegisterAuthenticationAgent()</link> ++ Authority using the <link ++ linkend="eggdbus-method-org.freedesktop.PolicyKit1.Authority.RegisterAuthenticationAgent">RegisterAuthenticationAgent()</link> + method. When services are needed, the authority will invoke +- methods on +- the <link linkend="eggdbus-interface-org.freedesktop.PolicyKit1.AuthenticationAgent">org.freedesktop.PolicyKit1.AuthenticationAgent</link> ++ methods on the <link ++ linkend="eggdbus-interface-org.freedesktop.PolicyKit1.AuthenticationAgent">org.freedesktop.PolicyKit1.AuthenticationAgent</link> + D-Bus interface. Once the user is authenticated, (a privileged +- part of) the agent invokes +- the <link linkend="eggdbus-method-org.freedesktop.PolicyKit1.Authority.AuthenticationAgentResponse">AuthenticationAgentResponse()</link> +- method. Note that the polkit Authority itself does not care +- how the agent authenticates the user. ++ part of) the agent invokes the <link ++ linkend="eggdbus-method-org.freedesktop.PolicyKit1.Authority.AuthenticationAgentResponse">AuthenticationAgentResponse()</link> ++ method. This method should be treated as an internal ++ implementation detail, and callers should use the public shared ++ library API to invoke it, which currently uses a setuid helper ++ program. + </para> + <para> + The <link linkend="ref-authentication-agent-api">libpolkit-agent-1</link> +diff --git a/src/polkit/polkitauthority.c b/src/polkit/polkitauthority.c +index ab6d3cd..6bd684a 100644 +--- a/src/polkit/polkitauthority.c ++++ b/src/polkit/polkitauthority.c +@@ -1492,6 +1492,14 @@ polkit_authority_authentication_agent_response (PolkitAuthority *authority, + gpointer user_data) + { + GVariant *identity_value; ++ /* Note that in reality, this API is only accessible to root, and ++ * only called from the setuid helper `polkit-agent-helper-1`. ++ * ++ * However, because this is currently public API, we avoid ++ * triggering warnings from ABI diff type programs by just grabbing ++ * the real uid of the caller here. ++ */ ++ uid_t uid = getuid (); + + g_return_if_fail (POLKIT_IS_AUTHORITY (authority)); + g_return_if_fail (cookie != NULL); +@@ -1501,8 +1509,9 @@ polkit_authority_authentication_agent_response (PolkitAuthority *authority, + identity_value = polkit_identity_to_gvariant (identity); + g_variant_ref_sink (identity_value); + g_dbus_proxy_call (authority->proxy, +- "AuthenticationAgentResponse", +- g_variant_new ("(s@(sa{sv}))", ++ "AuthenticationAgentResponse2", ++ g_variant_new ("(us@(sa{sv}))", ++ (guint32)uid, + cookie, + identity_value), + G_DBUS_CALL_FLAGS_NONE, +diff --git a/src/polkitbackend/polkitbackendauthority.c b/src/polkitbackend/polkitbackendauthority.c +index 601a974..03a4e84 100644 +--- a/src/polkitbackend/polkitbackendauthority.c ++++ b/src/polkitbackend/polkitbackendauthority.c +@@ -355,6 +355,7 @@ polkit_backend_authority_unregister_authentication_agent (PolkitBackendAuthority + gboolean + polkit_backend_authority_authentication_agent_response (PolkitBackendAuthority *authority, + PolkitSubject *caller, ++ uid_t uid, + const gchar *cookie, + PolkitIdentity *identity, + GError **error) +@@ -373,7 +374,7 @@ polkit_backend_authority_authentication_agent_response (PolkitBackendAuthority + } + else + { +- return klass->authentication_agent_response (authority, caller, cookie, identity, error); ++ return klass->authentication_agent_response (authority, caller, uid, cookie, identity, error); + } + } + +@@ -587,6 +588,11 @@ static const gchar *server_introspection_data = + " <arg type='s' name='cookie' direction='in'/>" + " <arg type='(sa{sv})' name='identity' direction='in'/>" + " </method>" ++ " <method name='AuthenticationAgentResponse2'>" ++ " <arg type='u' name='uid' direction='in'/>" ++ " <arg type='s' name='cookie' direction='in'/>" ++ " <arg type='(sa{sv})' name='identity' direction='in'/>" ++ " </method>" + " <method name='EnumerateTemporaryAuthorizations'>" + " <arg type='(sa{sv})' name='subject' direction='in'/>" + " <arg type='a(ss(sa{sv})tt)' name='temporary_authorizations' direction='out'/>" +@@ -1035,6 +1041,57 @@ server_handle_authentication_agent_response (Server *server, + error = NULL; + if (!polkit_backend_authority_authentication_agent_response (server->authority, + caller, ++ (uid_t)-1, ++ cookie, ++ identity, ++ &error)) ++ { ++ g_dbus_method_invocation_return_gerror (invocation, error); ++ g_error_free (error); ++ goto out; ++ } ++ ++ g_dbus_method_invocation_return_value (invocation, g_variant_new ("()")); ++ ++ out: ++ if (identity != NULL) ++ g_object_unref (identity); ++} ++ ++static void ++server_handle_authentication_agent_response2 (Server *server, ++ GVariant *parameters, ++ PolkitSubject *caller, ++ GDBusMethodInvocation *invocation) ++{ ++ const gchar *cookie; ++ GVariant *identity_gvariant; ++ PolkitIdentity *identity; ++ GError *error; ++ guint32 uid; ++ ++ identity = NULL; ++ ++ g_variant_get (parameters, ++ "(u&s@(sa{sv}))", ++ &uid, ++ &cookie, ++ &identity_gvariant); ++ ++ error = NULL; ++ identity = polkit_identity_new_for_gvariant (identity_gvariant, &error); ++ if (identity == NULL) ++ { ++ g_prefix_error (&error, "Error getting identity: "); ++ g_dbus_method_invocation_return_gerror (invocation, error); ++ g_error_free (error); ++ goto out; ++ } ++ ++ error = NULL; ++ if (!polkit_backend_authority_authentication_agent_response (server->authority, ++ caller, ++ (uid_t)uid, + cookie, + identity, + &error)) +@@ -1222,6 +1279,8 @@ server_handle_method_call (GDBusConnection *connection, + server_handle_unregister_authentication_agent (server, parameters, caller, invocation); + else if (g_strcmp0 (method_name, "AuthenticationAgentResponse") == 0) + server_handle_authentication_agent_response (server, parameters, caller, invocation); ++ else if (g_strcmp0 (method_name, "AuthenticationAgentResponse2") == 0) ++ server_handle_authentication_agent_response2 (server, parameters, caller, invocation); + else if (g_strcmp0 (method_name, "EnumerateTemporaryAuthorizations") == 0) + server_handle_enumerate_temporary_authorizations (server, parameters, caller, invocation); + else if (g_strcmp0 (method_name, "RevokeTemporaryAuthorizations") == 0) +diff --git a/src/polkitbackend/polkitbackendauthority.h b/src/polkitbackend/polkitbackendauthority.h +index f9f7385..88df82e 100644 +--- a/src/polkitbackend/polkitbackendauthority.h ++++ b/src/polkitbackend/polkitbackendauthority.h +@@ -147,6 +147,7 @@ struct _PolkitBackendAuthorityClass + + gboolean (*authentication_agent_response) (PolkitBackendAuthority *authority, + PolkitSubject *caller, ++ uid_t uid, + const gchar *cookie, + PolkitIdentity *identity, + GError **error); +@@ -249,6 +250,7 @@ gboolean polkit_backend_authority_unregister_authentication_agent (PolkitBackend + + gboolean polkit_backend_authority_authentication_agent_response (PolkitBackendAuthority *authority, + PolkitSubject *caller, ++ uid_t uid, + const gchar *cookie, + PolkitIdentity *identity, + GError **error); +diff --git a/src/polkitbackend/polkitbackendinteractiveauthority.c b/src/polkitbackend/polkitbackendinteractiveauthority.c +index 15adc6a..96725f7 100644 +--- a/src/polkitbackend/polkitbackendinteractiveauthority.c ++++ b/src/polkitbackend/polkitbackendinteractiveauthority.c +@@ -108,8 +108,9 @@ static AuthenticationAgent *get_authentication_agent_for_subject (PolkitBackendI + PolkitSubject *subject); + + +-static AuthenticationSession *get_authentication_session_for_cookie (PolkitBackendInteractiveAuthority *authority, +- const gchar *cookie); ++static AuthenticationSession *get_authentication_session_for_uid_and_cookie (PolkitBackendInteractiveAuthority *authority, ++ uid_t uid, ++ const gchar *cookie); + + static GList *get_authentication_sessions_initiated_by_system_bus_unique_name (PolkitBackendInteractiveAuthority *authority, + const gchar *system_bus_unique_name); +@@ -169,6 +170,7 @@ static gboolean polkit_backend_interactive_authority_unregister_authentication_a + + static gboolean polkit_backend_interactive_authority_authentication_agent_response (PolkitBackendAuthority *authority, + PolkitSubject *caller, ++ uid_t uid, + const gchar *cookie, + PolkitIdentity *identity, + GError **error); +@@ -440,6 +442,7 @@ struct AuthenticationAgent + { + volatile gint ref_count; + ++ uid_t creator_uid; + PolkitSubject *scope; + guint64 serial; + +@@ -1603,6 +1606,7 @@ authentication_agent_unref (AuthenticationAgent *agent) + static AuthenticationAgent * + authentication_agent_new (guint64 serial, + PolkitSubject *scope, ++ PolkitIdentity *creator, + const gchar *unique_system_bus_name, + const gchar *locale, + const gchar *object_path, +@@ -1611,6 +1615,10 @@ authentication_agent_new (guint64 serial, + { + AuthenticationAgent *agent; + GDBusProxy *proxy; ++ PolkitUnixUser *creator_user; ++ ++ g_assert (POLKIT_IS_UNIX_USER (creator)); ++ creator_user = POLKIT_UNIX_USER (creator); + + if (!g_variant_is_object_path (object_path)) + { +@@ -1638,6 +1646,7 @@ authentication_agent_new (guint64 serial, + agent->ref_count = 1; + agent->serial = serial; + agent->scope = g_object_ref (scope); ++ agent->creator_uid = (uid_t)polkit_unix_user_get_uid (creator_user); + agent->object_path = g_strdup (object_path); + agent->unique_system_bus_name = g_strdup (unique_system_bus_name); + agent->locale = g_strdup (locale); +@@ -1736,8 +1745,9 @@ get_authentication_agent_for_subject (PolkitBackendInteractiveAuthority *authori + } + + static AuthenticationSession * +-get_authentication_session_for_cookie (PolkitBackendInteractiveAuthority *authority, +- const gchar *cookie) ++get_authentication_session_for_uid_and_cookie (PolkitBackendInteractiveAuthority *authority, ++ uid_t uid, ++ const gchar *cookie) + { + PolkitBackendInteractiveAuthorityPrivate *priv; + GHashTableIter hash_iter; +@@ -1755,6 +1765,23 @@ get_authentication_session_for_cookie (PolkitBackendInteractiveAuthority *author + { + GList *l; + ++ /* We need to ensure that if somehow we have duplicate cookies ++ * due to wrapping, that the cookie used is matched to the user ++ * who called AuthenticationAgentResponse2. See ++ * http://lists.freedesktop.org/archives/polkit-devel/2015-June/000425.html ++ * ++ * Except if the legacy AuthenticationAgentResponse is invoked, ++ * we don't know the uid and hence use -1. Continue to support ++ * the old behavior for backwards compatibility, although everyone ++ * who is using our own setuid helper will automatically be updated ++ * to the new API. ++ */ ++ if (uid != (uid_t)-1) ++ { ++ if (agent->creator_uid != uid) ++ continue; ++ } ++ + for (l = agent->active_sessions; l != NULL; l = l->next) + { + AuthenticationSession *session = l->data; +@@ -2544,6 +2571,7 @@ polkit_backend_interactive_authority_register_authentication_agent (PolkitBacken + priv->agent_serial++; + agent = authentication_agent_new (priv->agent_serial, + subject, ++ user_of_caller, + polkit_system_bus_name_get_name (POLKIT_SYSTEM_BUS_NAME (caller)), + locale, + object_path, +@@ -2757,6 +2785,7 @@ polkit_backend_interactive_authority_unregister_authentication_agent (PolkitBack + static gboolean + polkit_backend_interactive_authority_authentication_agent_response (PolkitBackendAuthority *authority, + PolkitSubject *caller, ++ uid_t uid, + const gchar *cookie, + PolkitIdentity *identity, + GError **error) +@@ -2799,7 +2828,7 @@ polkit_backend_interactive_authority_authentication_agent_response (PolkitBacken + } + + /* find the authentication session */ +- session = get_authentication_session_for_cookie (interactive_authority, cookie); ++ session = get_authentication_session_for_uid_and_cookie (interactive_authority, uid, cookie); + if (session == NULL) + { + g_set_error (error, +-- +cgit v0.10.2 + +--- ./configure.ac.orig ++++ ./configure.ac +@@ -122,7 +122,7 @@ + changequote([,])dnl + fi + +-PKG_CHECK_MODULES(GLIB, [gio-2.0 >= 2.28.0]) ++PKG_CHECK_MODULES(GLIB, [gmodule-2.0 gio-unix-2.0 gio-2.0 >= 2.30.0]) + AC_SUBST(GLIB_CFLAGS) + AC_SUBST(GLIB_LIBS) + |