[PATCH xserver v2] xorg-wrapper: when starting the server as root, reset its environment

[Julien Cristau]

When the server is privileged, we shouldn't be passing the user's
environment directly.

Clearing the environment is recommended by the libdbus maintainers, see
https://bugs.freedesktop.org/show_bug.cgi?id=52202

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=83849
Signed-off-by: Julien Cristau <jcristau at debian.org>

v2: rename envp to empty_envp (Jeremy)
---
 hw/xfree86/xorg-wrapper.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/hw/xfree86/xorg-wrapper.c b/hw/xfree86/xorg-wrapper.c
index 22e97ad..f2c7c2b 100644
--- a/hw/xfree86/xorg-wrapper.c
+++ b/hw/xfree86/xorg-wrapper.c
@@ -190,6 +190,7 @@ int main(int argc, char *argv[])
     int total_cards = 0;
     int allowed = CONSOLE_ONLY;
     int needs_root_rights = -1;
+    char *const empty_envp[1] = { NULL, };
 
     progname = argv[0];
 
@@ -265,7 +266,10 @@ int main(int argc, char *argv[])
     }
 
     argv[0] = buf;
-    (void) execv(argv[0], argv);
+    if (getuid() == geteuid())
+        (void) execv(argv[0], argv);
+    else
+        (void) execve(argv[0], argv, empty_envp);
     fprintf(stderr, "%s: Failed to execute %s: %s\n",
         progname, buf, strerror(errno));
     exit(1);
-- 
2.6.1