528 lines
19 KiB
Diff
528 lines
19 KiB
Diff
From 709db95bff5d88ed2d9d5911e8050cacb4f46921 Mon Sep 17 00:00:00 2001
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From: panchenbo <panchenbo@uniontech.com>
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Date: Sun, 25 Apr 2021 18:28:22 +0800
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Subject: [PATCH] multi-pipe mode
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---
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liblightdm-gobject/greeter.c | 5 +-
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src/greeter.c | 9 ++--
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src/session-child.c | 100 ++++++++++++++++++++++++++++++-----
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src/session.c | 100 +++++++++++++++++++++++++++++++++--
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src/session.h | 7 +++
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5 files changed, 200 insertions(+), 21 deletions(-)
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diff --git a/liblightdm-gobject/greeter.c b/liblightdm-gobject/greeter.c
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index fd1763c..78c3981 100644
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--- a/liblightdm-gobject/greeter.c
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+++ b/liblightdm-gobject/greeter.c
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@@ -652,7 +652,6 @@ handle_prompt_authentication (LightDMGreeter *greeter, guint8 *message, gsize me
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g_list_free_full (priv->responses_received, g_free);
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priv->responses_received = NULL;
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- priv->n_responses_waiting = 0;
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guint32 n_messages = read_int (message, message_length, offset);
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g_debug ("Prompt user with %d message(s)", n_messages);
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@@ -713,6 +712,8 @@ handle_end_authentication (LightDMGreeter *greeter, guint8 *message, gsize messa
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priv->is_authenticated = (return_code == 0);
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priv->in_authentication = FALSE;
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+ // reset
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+ priv->n_responses_waiting = 0;
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g_signal_emit (G_OBJECT (greeter), signals[AUTHENTICATION_COMPLETE], 0);
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}
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@@ -1330,6 +1331,8 @@ lightdm_greeter_authenticate (LightDMGreeter *greeter, const gchar *username, GE
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priv->cancelling_authentication = FALSE;
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priv->authenticate_sequence_number++;
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priv->in_authentication = TRUE;
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+ // reset
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+ priv->n_responses_waiting = 0;
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priv->is_authenticated = FALSE;
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if (username != priv->authentication_user)
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{
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diff --git a/src/greeter.c b/src/greeter.c
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index 383e1f8..fc4850d 100644
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--- a/src/greeter.c
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+++ b/src/greeter.c
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@@ -394,6 +394,7 @@ pam_messages_cb (Session *session, Greeter *greeter)
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}
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write_message (greeter, message, offset);
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+ g_debug ("Prompt greeter with %d n_prompts", n_prompts);
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/* Continue immediately if nothing to respond with */
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// FIXME: Should probably give the greeter a chance to ack the message
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if (n_prompts == 0)
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@@ -645,8 +646,8 @@ handle_continue_authentication (Greeter *greeter, gchar **secrets)
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if (priv->authentication_session == NULL)
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return;
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- int messages_length = session_get_messages_length (priv->authentication_session);
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- const struct pam_message *messages = session_get_messages (priv->authentication_session);
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+ int messages_length = session_get_prompt_messages_length (priv->authentication_session);
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+ const struct pam_message *messages = session_get_prompt_messages (priv->authentication_session);
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/* Check correct number of responses */
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int n_prompts = 0;
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@@ -658,7 +659,7 @@ handle_continue_authentication (Greeter *greeter, gchar **secrets)
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}
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if (g_strv_length (secrets) != n_prompts)
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{
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- session_respond_error (priv->authentication_session, PAM_CONV_ERR);
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+ session_prompt_respond_error (priv->authentication_session, PAM_CONV_ERR);
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return;
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}
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@@ -678,7 +679,7 @@ handle_continue_authentication (Greeter *greeter, gchar **secrets)
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}
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}
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- session_respond (priv->authentication_session, response);
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+ session_prompt_respond (priv->authentication_session, response);
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for (int i = 0; i < messages_length; i++)
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secure_free (greeter, response[i].resp);
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diff --git a/src/session-child.c b/src/session-child.c
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index eef51e4..64716b2 100644
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--- a/src/session-child.c
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+++ b/src/session-child.c
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@@ -16,6 +16,7 @@
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#include <utmp.h>
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#include <utmpx.h>
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#include <sys/mman.h>
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+#include <pthread.h>
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#if HAVE_LIBAUDIT
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#include <libaudit.h>
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@@ -37,6 +38,8 @@ static GPid child_pid = 0;
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/* Pipe to communicate with daemon */
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static int from_daemon_output = 0;
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static int to_daemon_input = 0;
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+/* Pipe to prompt with daemon */
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+static int from_daemon_output_prompt = 0;
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static gboolean is_interactive;
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static gboolean do_authenticate;
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@@ -72,6 +75,16 @@ read_data (void *buf, size_t count)
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return n_read;
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}
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+static ssize_t
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+read_prompt_data (void *buf, size_t count)
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+{
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+ ssize_t n_read = read (from_daemon_output_prompt, buf, count);
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+ if (n_read < 0)
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+ g_printerr ("Error reading prompt from daemon: %s\n", strerror (errno));
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+
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+ return n_read;
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+}
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+
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static gchar *
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read_string_full (void* (*alloc_fn)(size_t n))
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{
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@@ -93,12 +106,34 @@ read_string_full (void* (*alloc_fn)(size_t n))
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return value;
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}
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+static gchar *
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+read_prompt_string_full (void* (*alloc_fn)(size_t n))
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+{
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+ int length;
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+ if (read_prompt_data (&length, sizeof (length)) <= 0)
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+ return NULL;
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+ if (length < 0)
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+ return NULL;
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+ if (length > MAX_STRING_LENGTH)
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+ {
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+ g_printerr ("Invalid string length %d from daemon\n", length);
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+ return NULL;
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+ }
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+
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+ gchar *value = (*alloc_fn) (sizeof (gchar) * (length + 1));
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+ read_prompt_data (value, length);
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+ value[length] = '\0';
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+
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+ return value;
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+}
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+
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static gchar *
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read_string (void)
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{
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return read_string_full (g_malloc);
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}
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+pthread_mutex_t mutex_msg;
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static int
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pam_conv_cb (int msg_length, const struct pam_message **msg, struct pam_response **resp, void *app_data)
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{
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@@ -106,18 +141,26 @@ pam_conv_cb (int msg_length, const struct pam_message **msg, struct pam_response
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if (authentication_complete)
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return PAM_SUCCESS;
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- /* Cancel authentication if requiring input */
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- if (!is_interactive)
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+ // 将普通消息和PAM_PROMPT_ECHO_X的消息分开，从lightdm中读取回复内容时使用不同的管道
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+ // 因为在lightdm的实现中处理PAM_PROMPT_ECHO_X时会一直等待greeter的消息，而其他消息则会立即给出响应结果
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+ int n_prompts = 0;
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+
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+ for (int i = 0; i < msg_length; i++)
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{
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- for (int i = 0; i < msg_length; i++)
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+ if (msg[i]->msg_style == PAM_PROMPT_ECHO_ON || msg[i]->msg_style == PAM_PROMPT_ECHO_OFF)
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{
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- if (msg[i]->msg_style == PAM_PROMPT_ECHO_ON || msg[i]->msg_style == PAM_PROMPT_ECHO_OFF)
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+ /* Cancel authentication if requiring input */
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+ if (!is_interactive)
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{
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g_printerr ("Stopping PAM conversation, interaction requested but not supported\n");
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return PAM_CONV_ERR;
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}
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- }
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+ ++n_prompts;
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+ }
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+ }
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+ if (!is_interactive)
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+ {
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/* Ignore informational messages */
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return PAM_SUCCESS;
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}
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@@ -125,6 +168,10 @@ pam_conv_cb (int msg_length, const struct pam_message **msg, struct pam_response
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/* Check if we changed user */
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gchar *username = NULL;
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pam_get_item (pam_handle, PAM_USER, (const void **) &username);
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+
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+ // lock for pam
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+ // 在pam模块中可能使用多线程调用此函数，加锁是为了保证消息在管道中的相对顺序
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+ pthread_mutex_lock(&mutex_msg);
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/* Notify the daemon */
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write_string (username);
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@@ -140,17 +187,39 @@ pam_conv_cb (int msg_length, const struct pam_message **msg, struct pam_response
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/* Get response */
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int error;
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- read_data (&error, sizeof (error));
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- if (error != PAM_SUCCESS)
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+ if (n_prompts) {
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+ // 只为普通消息加锁，如果 PAM_PROMPT_ECHO_X 类型的消息也从多个线程发送则可能存在风险
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+ // unlock for read message
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+ pthread_mutex_unlock(&mutex_msg);
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+ read_prompt_data (&error, sizeof (error));
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+ } else {
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+ read_data (&error, sizeof (error));
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+ }
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+ if (error != PAM_SUCCESS) {
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+ if (!n_prompts) {
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+ // unlock for read message
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+ pthread_mutex_unlock(&mutex_msg);
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+ }
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return error;
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+ }
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struct pam_response *response = calloc (msg_length, sizeof (struct pam_response));
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for (int i = 0; i < msg_length; i++)
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{
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struct pam_response *r = &response[i];
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// callers of this function inside pam will expect to be able to call
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// free() on the strings we give back. So alloc with malloc.
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- r->resp = read_string_full (malloc);
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- read_data (&r->resp_retcode, sizeof (r->resp_retcode));
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+ if (n_prompts) {
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+ r->resp = read_prompt_string_full (malloc);
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+ read_prompt_data (&r->resp_retcode, sizeof (r->resp_retcode));
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+ } else {
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+ r->resp = read_string_full (malloc);
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+ read_data (&r->resp_retcode, sizeof (r->resp_retcode));
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+ }
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+ }
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+
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+ if (!n_prompts) {
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+ // unlock for read message
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+ pthread_mutex_unlock(&mutex_msg);
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}
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*resp = response;
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@@ -262,22 +331,24 @@ session_child_run (int argc, char **argv)
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close (fd);
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/* Get the pipe from the daemon */
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- if (argc != 4)
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+ if (argc != 5)
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{
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- g_printerr ("Usage: lightdm --session-child INPUTFD OUTPUTFD\n");
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+ g_printerr ("Usage: lightdm --session-child INPUTFD OUTPUTFD INPUTFD_PROMPT\n");
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return EXIT_FAILURE;
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}
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from_daemon_output = atoi (argv[2]);
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to_daemon_input = atoi (argv[3]);
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- if (from_daemon_output == 0 || to_daemon_input == 0)
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+ from_daemon_output_prompt = atoi (argv[4]);
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+ if (from_daemon_output == 0 || to_daemon_input == 0 || from_daemon_output_prompt == 0)
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{
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- g_printerr ("Invalid file descriptors %s %s\n", argv[2], argv[3]);
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+ g_printerr ("Invalid file descriptors %s %s %s\n", argv[2], argv[3], argv[4]);
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return EXIT_FAILURE;
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}
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/* Don't let these pipes leak to the command we will run */
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fcntl (from_daemon_output, F_SETFD, FD_CLOEXEC);
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fcntl (to_daemon_input, F_SETFD, FD_CLOEXEC);
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+ fcntl (from_daemon_output_prompt, F_SETFD, FD_CLOEXEC);
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/* Read a version number so we can handle upgrades (i.e. a newer version of session child is run for an old daemon */
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int version;
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@@ -330,7 +401,10 @@ session_child_run (int argc, char **argv)
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{
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const gchar *new_username;
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+ // init mutex for pam_conv_cb
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+ pthread_mutex_init(&mutex_msg, 0);
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authentication_result = pam_authenticate (pam_handle, 0);
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+ pthread_mutex_destroy(&mutex_msg);
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/* See what user we ended up as */
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if (pam_get_item (pam_handle, PAM_USER, (const void **) &new_username) != PAM_SUCCESS)
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diff --git a/src/session.c b/src/session.c
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index 2ea9352..12ae60a 100644
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--- a/src/session.c
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+++ b/src/session.c
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@@ -52,6 +52,7 @@ typedef struct
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/* Pipes to talk to child */
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int to_child_input;
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int from_child_output;
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+ int to_child_prompt_input;
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GIOChannel *from_child_channel;
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guint from_child_watch;
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guint child_watch;
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@@ -77,6 +78,9 @@ typedef struct
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/* Messages being requested by PAM */
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int messages_length;
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struct pam_message *messages;
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+ /* Prompt Messages being requested by PAM */
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+ int prompt_messages_length;
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+ struct pam_message *prompt_messages;
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/* Authentication result from PAM */
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gboolean authentication_started;
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@@ -382,6 +386,14 @@ write_data (Session *session, const void *buf, size_t count)
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l_warning (session, "Error writing to session: %s", strerror (errno));
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}
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+static void
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+write_prompt_data (Session *session, const void *buf, size_t count)
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+{
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+ SessionPrivate *priv = session_get_instance_private (session);
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+ if (write (priv->to_child_prompt_input, buf, count) != count)
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+ l_warning (session, "Error writing prompt to session: %s", strerror (errno));
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+}
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+
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static void
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write_string (Session *session, const char *value)
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{
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@@ -391,6 +403,15 @@ write_string (Session *session, const char *value)
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write_data (session, value, sizeof (char) * length);
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}
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+static void
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+write_prompt_string (Session *session, const char *value)
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+{
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+ int length = value ? strlen (value) : -1;
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+ write_prompt_data (session, &length, sizeof (length));
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+ if (value)
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+ write_prompt_data (session, value, sizeof (char) * length);
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+}
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+
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static void
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write_xauth (Session *session, XAuthority *x_authority)
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{
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@@ -534,6 +555,8 @@ from_child_cb (GIOChannel *source, GIOCondition condition, gpointer data)
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}
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else
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{
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+ gboolean n_prompts = 0;
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+
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priv->messages_length = 0;
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read_from_child (session, &priv->messages_length, sizeof (priv->messages_length));
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priv->messages = calloc (priv->messages_length, sizeof (struct pam_message));
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@@ -542,6 +565,13 @@ from_child_cb (GIOChannel *source, GIOCondition condition, gpointer data)
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struct pam_message *m = &priv->messages[i];
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read_from_child (session, &m->msg_style, sizeof (m->msg_style));
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m->msg = read_string_from_child (session);
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+ if (m->msg_style == PAM_PROMPT_ECHO_OFF || m->msg_style == PAM_PROMPT_ECHO_ON)
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+ ++n_prompts;
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+ }
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+ // for prompt message
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+ if (n_prompts) {
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+ priv->prompt_messages_length = priv->messages_length;
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+ priv->prompt_messages = priv->messages;
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}
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l_debug (session, "Got %d message(s) from PAM", priv->messages_length);
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@@ -585,15 +615,17 @@ session_real_start (Session *session)
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display_server_connect_session (priv->display_server, session);
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/* Create pipes to talk to the child */
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- int to_child_pipe[2], from_child_pipe[2];
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- if (pipe (to_child_pipe) < 0 || pipe (from_child_pipe) < 0)
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+ int to_child_pipe[2], from_child_pipe[2], to_child_prompt_pipe[2];
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+ if (pipe (to_child_pipe) < 0 || pipe (from_child_pipe) < 0 || pipe (to_child_prompt_pipe) < 0)
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{
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g_warning ("Failed to create pipe to communicate with session process: %s", strerror (errno));
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return FALSE;
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}
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int to_child_output = to_child_pipe[0];
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+ int to_child_prompt_output = to_child_prompt_pipe[0];
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priv->to_child_input = to_child_pipe[1];
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priv->from_child_output = from_child_pipe[0];
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+ priv->to_child_prompt_input = to_child_prompt_pipe[1];
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int from_child_input = from_child_pipe[1];
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priv->from_child_channel = g_io_channel_unix_new (priv->from_child_output);
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priv->from_child_watch = g_io_add_watch (priv->from_child_channel, G_IO_IN | G_IO_HUP, from_child_cb, session);
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@@ -601,6 +633,7 @@ session_real_start (Session *session)
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/* Don't allow the daemon end of the pipes to be accessed in child processes */
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fcntl (priv->to_child_input, F_SETFD, FD_CLOEXEC);
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fcntl (priv->from_child_output, F_SETFD, FD_CLOEXEC);
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+ fcntl (priv->to_child_prompt_input, F_SETFD, FD_CLOEXEC);
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/* Create the guest account if it is one */
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if (priv->is_guest && priv->username == NULL)
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@@ -613,6 +646,7 @@ session_real_start (Session *session)
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/* Run the child */
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g_autofree gchar *arg0 = g_strdup_printf ("%d", to_child_output);
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g_autofree gchar *arg1 = g_strdup_printf ("%d", from_child_input);
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+ g_autofree gchar *arg2 = g_strdup_printf ("%d", to_child_prompt_output);
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priv->pid = fork ();
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if (priv->pid == 0)
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{
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@@ -620,7 +654,7 @@ session_real_start (Session *session)
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execlp ("lightdm",
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"lightdm",
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"--session-child",
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- arg0, arg1, NULL);
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+ arg0, arg1, arg2, NULL);
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_exit (EXIT_FAILURE);
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}
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@@ -642,6 +676,7 @@ session_real_start (Session *session)
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/* Close the ends of the pipes we don't need */
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close (to_child_output);
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close (from_child_input);
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+ close (to_child_prompt_output);
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/* Indicate what version of the protocol we are using */
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int version = 3;
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@@ -702,6 +737,11 @@ session_respond (Session *session, struct pam_response *response)
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write_data (session, &response[i].resp_retcode, sizeof (response[i].resp_retcode));
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}
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+ if (priv->messages == priv->prompt_messages) {
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+ l_warning (session, "%s", "Current message is prompt message");
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+ return;
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+ }
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+
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/* Delete the old messages */
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for (int i = 0; i < priv->messages_length; i++)
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g_free ((char *) priv->messages[i].msg);
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@@ -710,6 +750,35 @@ session_respond (Session *session, struct pam_response *response)
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priv->messages_length = 0;
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||
}
|
||
|
||
+void
|
||
+session_prompt_respond (Session *session, struct pam_response *response)
|
||
+{
|
||
+ SessionPrivate *priv = session_get_instance_private (session);
|
||
+
|
||
+ g_return_if_fail (session != NULL);
|
||
+
|
||
+ int error = PAM_SUCCESS;
|
||
+ write_prompt_data (session, &error, sizeof (error));
|
||
+ for (int i = 0; i < priv->prompt_messages_length; i++)
|
||
+ {
|
||
+ write_prompt_string (session, response[i].resp);
|
||
+ write_prompt_data (session, &response[i].resp_retcode, sizeof (response[i].resp_retcode));
|
||
+ }
|
||
+
|
||
+ // clear
|
||
+ if (priv->messages == priv->prompt_messages) {
|
||
+ priv->messages = NULL;
|
||
+ priv->messages_length = 0;
|
||
+ }
|
||
+
|
||
+ /* Delete the old messages */
|
||
+ for (int i = 0; i < priv->prompt_messages_length; i++)
|
||
+ g_free ((char *) priv->prompt_messages[i].msg);
|
||
+ g_free (priv->prompt_messages);
|
||
+ priv->prompt_messages = NULL;
|
||
+ priv->prompt_messages_length = 0;
|
||
+}
|
||
+
|
||
void
|
||
session_respond_error (Session *session, int error)
|
||
{
|
||
@@ -719,6 +788,15 @@ session_respond_error (Session *session, int error)
|
||
write_data (session, &error, sizeof (error));
|
||
}
|
||
|
||
+void
|
||
+session_prompt_respond_error (Session *session, int error)
|
||
+{
|
||
+ g_return_if_fail (session != NULL);
|
||
+ g_return_if_fail (error != PAM_SUCCESS);
|
||
+
|
||
+ write_prompt_data (session, &error, sizeof (error));
|
||
+}
|
||
+
|
||
int
|
||
session_get_messages_length (Session *session)
|
||
{
|
||
@@ -727,6 +805,22 @@ session_get_messages_length (Session *session)
|
||
return priv->messages_length;
|
||
}
|
||
|
||
+int
|
||
+session_get_prompt_messages_length(Session *session)
|
||
+{
|
||
+ SessionPrivate *priv = session_get_instance_private (session);
|
||
+ g_return_val_if_fail (session != NULL, 0);
|
||
+ return priv->prompt_messages_length;
|
||
+}
|
||
+
|
||
+const struct pam_message *
|
||
+session_get_prompt_messages(Session *session)
|
||
+{
|
||
+ SessionPrivate *priv = session_get_instance_private (session);
|
||
+ g_return_val_if_fail (session != NULL, NULL);
|
||
+ return priv->prompt_messages;
|
||
+}
|
||
+
|
||
const struct pam_message *
|
||
session_get_messages (Session *session)
|
||
{
|
||
diff --git a/src/session.h b/src/session.h
|
||
index 350cf3b..de15ae4 100644
|
||
--- a/src/session.h
|
||
+++ b/src/session.h
|
||
@@ -124,12 +124,19 @@ const gchar *session_get_console_kit_cookie (Session *session);
|
||
|
||
void session_respond (Session *session, struct pam_response *response);
|
||
|
||
+void session_prompt_respond (Session *session, struct pam_response *response);
|
||
+
|
||
void session_respond_error (Session *session, int error);
|
||
|
||
+void session_prompt_respond_error (Session *session, int error);
|
||
+
|
||
int session_get_messages_length (Session *session);
|
||
|
||
const struct pam_message *session_get_messages (Session *session);
|
||
|
||
+int session_get_prompt_messages_length (Session *session);
|
||
+const struct pam_message *session_get_prompt_messages (Session *session);
|
||
+
|
||
gboolean session_get_is_authenticated (Session *session);
|
||
|
||
int session_get_authentication_result (Session *session);
|
||
--
|
||
2.20.1
|
||
|