121 lines
4.4 KiB
Diff
121 lines
4.4 KiB
Diff
From 7650ad1e08ab13bdb461783c4995d186d9392840 Mon Sep 17 00:00:00 2001
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From: Rui Matos <tiagomatos@gmail.com>
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Date: Thu, 6 Feb 2014 18:41:18 +0100
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Subject: [PATCH] PolkitAgentSession: fix race between child and io watches
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The helper flushes and fdatasyncs stdout and stderr before terminating
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but this doesn't guarantee that our io watch is called before our
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child watch. This means that we can end up with a successful return
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from the helper which we still report as a failure.
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If we add G_IO_HUP and G_IO_ERR to the conditions we look for in the
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io watch and the child terminates we still run the io watch handler
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which will complete the session.
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This means that the child watch is in fact needless and we can remove
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it.
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https://bugs.freedesktop.org/show_bug.cgi?id=60847
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---
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src/polkitagent/polkitagentsession.c | 47 +++++++++---------------------------
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1 file changed, 11 insertions(+), 36 deletions(-)
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diff --git a/src/polkitagent/polkitagentsession.c b/src/polkitagent/polkitagentsession.c
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index 1c7a2dc..f014773 100644
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--- a/src/polkitagent/polkitagentsession.c
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+++ b/src/polkitagent/polkitagentsession.c
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@@ -92,7 +92,6 @@ struct _PolkitAgentSession
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int child_stdout;
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GPid child_pid;
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- GSource *child_watch_source;
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GSource *child_stdout_watch_source;
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GIOChannel *child_stdout_channel;
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@@ -377,13 +376,6 @@ kill_helper (PolkitAgentSession *session)
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session->child_pid = 0;
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}
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- if (session->child_watch_source != NULL)
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- {
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- g_source_destroy (session->child_watch_source);
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- g_source_unref (session->child_watch_source);
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- session->child_watch_source = NULL;
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- }
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-
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if (session->child_stdout_watch_source != NULL)
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{
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g_source_destroy (session->child_stdout_watch_source);
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@@ -429,26 +421,6 @@ complete_session (PolkitAgentSession *session,
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}
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}
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-static void
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-child_watch_func (GPid pid,
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- gint status,
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- gpointer user_data)
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-{
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- PolkitAgentSession *session = POLKIT_AGENT_SESSION (user_data);
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-
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- if (G_UNLIKELY (_show_debug ()))
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- {
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- g_print ("PolkitAgentSession: in child_watch_func for pid %d (WIFEXITED=%d WEXITSTATUS=%d)\n",
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- (gint) pid,
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- WIFEXITED(status),
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- WEXITSTATUS(status));
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- }
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-
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- /* kill all the watches we have set up, except for the child since it has exited already */
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- session->child_pid = 0;
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- complete_session (session, FALSE);
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-}
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-
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static gboolean
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io_watch_have_data (GIOChannel *channel,
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GIOCondition condition,
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@@ -475,10 +447,13 @@ io_watch_have_data (GIOChannel *channel,
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NULL,
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NULL,
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&error);
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- if (error != NULL)
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+ if (error != NULL || line == NULL)
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{
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- g_warning ("Error reading line from helper: %s", error->message);
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- g_error_free (error);
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+ /* In case we get just G_IO_HUP, line is NULL but error is
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+ unset.*/
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+ g_warning ("Error reading line from helper: %s",
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+ error ? error->message : "nothing to read");
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+ g_clear_error (&error);
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complete_session (session, FALSE);
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goto out;
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@@ -540,6 +515,9 @@ io_watch_have_data (GIOChannel *channel,
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g_free (line);
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g_free (unescaped);
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+ if (condition & (G_IO_ERR | G_IO_HUP))
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+ complete_session (session, FALSE);
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+
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/* keep the IOChannel around */
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return TRUE;
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}
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@@ -650,12 +628,9 @@ polkit_agent_session_initiate (PolkitAgentSession *session)
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if (G_UNLIKELY (_show_debug ()))
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g_print ("PolkitAgentSession: spawned helper with pid %d\n", (gint) session->child_pid);
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- session->child_watch_source = g_child_watch_source_new (session->child_pid);
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- g_source_set_callback (session->child_watch_source, (GSourceFunc) child_watch_func, session, NULL);
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- g_source_attach (session->child_watch_source, g_main_context_get_thread_default ());
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-
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session->child_stdout_channel = g_io_channel_unix_new (session->child_stdout);
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- session->child_stdout_watch_source = g_io_create_watch (session->child_stdout_channel, G_IO_IN);
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+ session->child_stdout_watch_source = g_io_create_watch (session->child_stdout_channel,
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+ G_IO_IN | G_IO_ERR | G_IO_HUP);
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g_source_set_callback (session->child_stdout_watch_source, (GSourceFunc) io_watch_have_data, session, NULL);
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g_source_attach (session->child_stdout_watch_source, g_main_context_get_thread_default ());
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--
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1.8.3.1
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