sesman: do not hardcode Xorg/X11rdp/Xvnc executables

In RHEL and its clones, /usr/bin/Xorg is set suid-root. To execute
Xorg with user privileges, /etc/pam.d/xserver needs be edited [1],
or suid bit of Xorg binary needs to be dropped.

In order to keep Xorg and /etc/pam.d/xserver untouched, preparing
non-suid version of Xorg as /usr/bin/Xorg.non-suid for example is
the simplest solution. However, Xorg.non-suid cannot be executed
since it is hardcoded to execute Xorg in sesman.

This change makes more flexible to execute Xorg with non-standard
name or not in PATH environment variable.

[1] https://www.centos.org/forums/viewtopic.php?t=21185
ulab-next-nosound
Koichiro IWAO 9 years ago
parent fb08623b66
commit cf2b629462

@ -63,6 +63,7 @@ EnableSyslog=1
SyslogLevel=DEBUG
[X11rdp]
param0=X11rdp
param1=-bs
param2=-ac
param3=-nolisten
@ -70,6 +71,7 @@ param4=tcp
param5=-uds
[Xvnc]
param0=Xvnc
param1=-bs
param2=-ac
param3=-nolisten
@ -79,6 +81,7 @@ param6=-dpi
param7=96
[Xorg]
param0=Xorg
param1=-config
param2=xrdp/xorg.conf
param3=-logfile

@ -412,9 +412,10 @@ session_start_fork(int width, int height, int bpp, char *username,
int pampid = 0;
int xpid = 0;
int i = 0;
char **xserver; /* absolute/relative path to Xorg/X11rdp/Xvnc */
char geometry[32];
char depth[32];
char screen[32];
char screen[32]; /* display number */
char text[256];
char passwd_file[256];
char *pfile;
@ -652,8 +653,12 @@ session_start_fork(int width, int height, int bpp, char *username,
xserver_params = list_create();
xserver_params->auto_free = 1;
/* get path of Xorg from config */
xserver = g_strdup(list_get_item(g_cfg->xorg_params, 0));
list_remove_item(g_cfg->xorg_params, 0);
/* these are the must have parameters */
list_add_item(xserver_params, (tintptr) g_strdup("Xorg"));
list_add_item(xserver_params, (tintptr) g_strdup(xserver));
list_add_item(xserver_params, (tintptr) g_strdup(screen));
/* additional parameters from sesman.ini file */
@ -674,7 +679,7 @@ session_start_fork(int width, int height, int bpp, char *username,
g_setenv("XRDP_START_HEIGHT", geometry, 1);
/* fire up Xorg */
g_execvp("Xorg", pp1);
g_execvp(xserver, pp1);
}
else if (type == SESMAN_SESSION_TYPE_XVNC)
{
@ -682,8 +687,12 @@ session_start_fork(int width, int height, int bpp, char *username,
xserver_params = list_create();
xserver_params->auto_free = 1;
/* get path of Xvnc from config */
xserver = g_strdup(list_get_item(g_cfg->vnc_params, 0));
list_remove_item(g_cfg->vnc_params, 0);
/* these are the must have parameters */
list_add_item(xserver_params, (tintptr)g_strdup("Xvnc"));
list_add_item(xserver_params, (tintptr)g_strdup(xserver));
list_add_item(xserver_params, (tintptr)g_strdup(screen));
list_add_item(xserver_params, (tintptr)g_strdup("-geometry"));
list_add_item(xserver_params, (tintptr)g_strdup(geometry));
@ -701,15 +710,19 @@ session_start_fork(int width, int height, int bpp, char *username,
list_add_item(xserver_params, 0);
pp1 = (char **)xserver_params->items;
log_message(LOG_LEVEL_INFO, "%s", dumpItemsToString(xserver_params, execvpparams, 2048));
g_execvp("Xvnc", pp1);
g_execvp(xserver, pp1);
}
else if (type == SESMAN_SESSION_TYPE_XRDP)
{
xserver_params = list_create();
xserver_params->auto_free = 1;
/* get path of X11rdp from config */
xserver = g_strdup(list_get_item(g_cfg->rdp_params, 0));
list_remove_item(g_cfg->rdp_params, 0);
/* these are the must have parameters */
list_add_item(xserver_params, (tintptr)g_strdup("X11rdp"));
list_add_item(xserver_params, (tintptr)g_strdup(xserver));
list_add_item(xserver_params, (tintptr)g_strdup(screen));
list_add_item(xserver_params, (tintptr)g_strdup("-geometry"));
list_add_item(xserver_params, (tintptr)g_strdup(geometry));
@ -725,7 +738,7 @@ session_start_fork(int width, int height, int bpp, char *username,
list_add_item(xserver_params, 0);
pp1 = (char **)xserver_params->items;
log_message(LOG_LEVEL_INFO, "%s", dumpItemsToString(xserver_params, execvpparams, 2048));
g_execvp("X11rdp", pp1);
g_execvp(xserver, pp1);
}
else
{

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