From ea544ffc18405237ccd95d28d7f45afef49aca17 Mon Sep 17 00:00:00 2001 From: Colin Walters 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: ``` - - - ``` 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 Reviewed-by: Miloslav Trmač Signed-off-by: Colin Walters 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 +#include #include #include @@ -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 #include #include +#include #include #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. + * + * - - - + * + * 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 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 Bug: https://bugs.freedesktop.org/show_bug.cgi?id=90837 CVE: CVE-2015-4625 Reported-by: Tavis Ormandy Reviewed-by: Miloslav Trmač Signed-off-by: Colin Walters 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 @@ - + 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 @@ - + + + + + + + + + + + + + + + + + + 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 TemporaryAuth IN String object_path) AuthenticationAgentResponse (IN String cookie, IN Identity identity) +AuthenticationAgentResponse2 (IN uint32 uid, IN String cookie, + IN Identity identity) EnumerateTemporaryAuthorizations (IN Subject subject, OUT Array<TemporaryAuthorization> temporary_authorizations) RevokeTemporaryAuthorizations (IN Subject subject) @@ -777,10 +779,52 @@ AuthenticationAgentResponse (IN String cookie, IN Identity identity) -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. + + + + IN String cookie: + + +The cookie identifying the authentication request that was passed to the authentication agent. + + + + + IN Identity identity: + + +A Identity struct describing what identity was authenticated. + + + + + + + AuthenticationAgentResponse2 () + +AuthenticationAgentResponse2 (IN uint32 uid, + IN String cookie, + IN Identity identity) + + +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. + IN uint32 uid: + + +The user id of the agent; normally this is the owner of the parent pid +of the process that invoked the internal setuid helper. + + + + IN String cookie: 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 @@ Authentication agents are provided by desktop environments. When an user session starts, the agent registers with the polkit - Authority using - the RegisterAuthenticationAgent() + Authority using the RegisterAuthenticationAgent() method. When services are needed, the authority will invoke - methods on - the org.freedesktop.PolicyKit1.AuthenticationAgent + methods on the org.freedesktop.PolicyKit1.AuthenticationAgent D-Bus interface. Once the user is authenticated, (a privileged - part of) the agent invokes - the AuthenticationAgentResponse() - method. Note that the polkit Authority itself does not care - how the agent authenticates the user. + part of) the agent invokes the AuthenticationAgentResponse() + 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. The libpolkit-agent-1 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 = " " " " " " + " " + " " + " " + " " + " " " " " " " " @@ -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)