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141 lines
5.9 KiB
141 lines
5.9 KiB
From 059f4f3999f1de506417611318c6f27db57fb689 Mon Sep 17 00:00:00 2001 |
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From: Marius Vollmer <mvollmer@redhat.com> |
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Date: Mon, 13 Feb 2023 14:12:52 +0200 |
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Subject: [PATCH] gdbus: Never buffer reads during server authentication |
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Otherwise, the content of the buffer is thrown away when switching |
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from reading via a GDataInputStream to unbuffered reads when waiting |
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for the "BEGIN" line. |
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|
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(The code already tried to protect against over-reading like this by |
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using unbuffered reads for the last few lines of the auth protocol, |
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but it might already be too late at that point. The buffer of the |
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GDataInputStream might already contain the "BEGIN" line for example.) |
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This matters when connecting a sd-bus client directly to a GDBus |
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client. A sd-bus client optimistically sends the whole auth |
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conversation in one go without waiting for intermediate replies. This |
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is done to improve performance for the many short-lived connections |
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that are typically made. |
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--- |
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gio/gdbusauth.c | 50 ++++++++++++++++++++++++++++++------------------- |
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1 file changed, 31 insertions(+), 19 deletions(-) |
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diff --git a/gio/gdbusauth.c b/gio/gdbusauth.c |
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index c430f0cf0..17c7d47b7 100644 |
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--- a/gio/gdbusauth.c |
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+++ b/gio/gdbusauth.c |
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@@ -933,7 +933,6 @@ _g_dbus_auth_run_server (GDBusAuth *auth, |
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{ |
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gboolean ret; |
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ServerState state; |
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- GDataInputStream *dis; |
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GDataOutputStream *dos; |
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GError *local_error; |
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gchar *line; |
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@@ -949,7 +948,6 @@ _g_dbus_auth_run_server (GDBusAuth *auth, |
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_g_dbus_auth_add_mechs (auth, observer); |
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ret = FALSE; |
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- dis = NULL; |
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dos = NULL; |
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mech = NULL; |
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negotiated_capabilities = 0; |
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@@ -965,13 +963,18 @@ _g_dbus_auth_run_server (GDBusAuth *auth, |
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goto out; |
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} |
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- dis = G_DATA_INPUT_STREAM (g_data_input_stream_new (g_io_stream_get_input_stream (auth->priv->stream))); |
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+ /* We use an extremely slow (but reliable) line reader for input |
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+ * instead of something buffered - this basically does a recvfrom() |
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+ * system call per character |
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+ * |
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+ * (the problem with using GDataInputStream's read_line is that |
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+ * because of buffering it might start reading into the first D-Bus |
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+ * message that appears after "BEGIN\r\n"....) |
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+ */ |
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+ |
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dos = G_DATA_OUTPUT_STREAM (g_data_output_stream_new (g_io_stream_get_output_stream (auth->priv->stream))); |
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- g_filter_input_stream_set_close_base_stream (G_FILTER_INPUT_STREAM (dis), FALSE); |
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g_filter_output_stream_set_close_base_stream (G_FILTER_OUTPUT_STREAM (dos), FALSE); |
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- g_data_input_stream_set_newline_type (dis, G_DATA_STREAM_NEWLINE_TYPE_CR_LF); |
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- |
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/* read the NUL-byte, possibly with credentials attached */ |
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#ifdef G_OS_UNIX |
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#ifndef G_CREDENTIALS_PREFER_MESSAGE_PASSING |
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@@ -1010,11 +1013,22 @@ _g_dbus_auth_run_server (GDBusAuth *auth, |
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} |
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else |
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{ |
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+ gchar c; |
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+ gssize num_read; |
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+ |
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local_error = NULL; |
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- (void)g_data_input_stream_read_byte (dis, cancellable, &local_error); |
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- if (local_error != NULL) |
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+ num_read = g_input_stream_read (g_io_stream_get_input_stream (auth->priv->stream), |
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+ &c, 1, |
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+ cancellable, &local_error); |
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+ if (num_read != 1 || local_error != NULL) |
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{ |
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- g_propagate_error (error, local_error); |
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+ if (local_error == NULL) |
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+ g_set_error_literal (error, |
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+ G_IO_ERROR, |
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+ G_IO_ERROR_FAILED, |
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+ _ ("Unexpected lack of content trying to read a byte")); |
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+ else |
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+ g_propagate_error (error, local_error); |
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goto out; |
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} |
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} |
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@@ -1050,7 +1064,10 @@ _g_dbus_auth_run_server (GDBusAuth *auth, |
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{ |
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case SERVER_STATE_WAITING_FOR_AUTH: |
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debug_print ("SERVER: WaitingForAuth"); |
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- line = _my_g_data_input_stream_read_line (dis, &line_length, cancellable, error); |
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+ line = _my_g_input_stream_read_line_safe (g_io_stream_get_input_stream (auth->priv->stream), |
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+ &line_length, |
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+ cancellable, |
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+ error); |
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debug_print ("SERVER: WaitingForAuth, read '%s'", line); |
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if (line == NULL) |
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goto out; |
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@@ -1260,7 +1277,10 @@ _g_dbus_auth_run_server (GDBusAuth *auth, |
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case SERVER_STATE_WAITING_FOR_DATA: |
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debug_print ("SERVER: WaitingForData"); |
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- line = _my_g_data_input_stream_read_line (dis, &line_length, cancellable, error); |
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+ line = _my_g_input_stream_read_line_safe (g_io_stream_get_input_stream (auth->priv->stream), |
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+ &line_length, |
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+ cancellable, |
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+ error); |
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debug_print ("SERVER: WaitingForData, read '%s'", line); |
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if (line == NULL) |
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goto out; |
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@@ -1299,13 +1319,6 @@ _g_dbus_auth_run_server (GDBusAuth *auth, |
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case SERVER_STATE_WAITING_FOR_BEGIN: |
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debug_print ("SERVER: WaitingForBegin"); |
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- /* Use extremely slow (but reliable) line reader - this basically |
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- * does a recvfrom() system call per character |
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- * |
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- * (the problem with using GDataInputStream's read_line is that because of |
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- * buffering it might start reading into the first D-Bus message that |
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- * appears after "BEGIN\r\n"....) |
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- */ |
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line = _my_g_input_stream_read_line_safe (g_io_stream_get_input_stream (auth->priv->stream), |
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&line_length, |
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cancellable, |
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@@ -1364,7 +1377,6 @@ _g_dbus_auth_run_server (GDBusAuth *auth, |
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out: |
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g_clear_object (&mech); |
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- g_clear_object (&dis); |
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g_clear_object (&dos); |
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g_clear_object (&own_credentials); |
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-- |
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2.41.0 |
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