add support for capabilities

[pulseaudio] / polyp / caps.c

diff --git a/polyp/caps.c b/polyp/caps.c
new file mode 100644 (file)
index 0000000..db00c60
--- /dev/null
+++ b/polyp/caps.c
@@ -0,0 +1,106 @@
+/* $Id$ */
+
+/***
+  This file is part of polypaudio.
+ 
+  polypaudio is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published
+  by the Free Software Foundation; either version 2 of the License,
+  or (at your option) any later version.
+ 
+  polypaudio is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  General Public License for more details.
+ 
+  You should have received a copy of the GNU General Public License
+  along with polypaudio; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+  USA.
+***/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <assert.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+
+#ifdef HAVE_SYS_CAPABILITY_H
+#include <sys/capability.h>
+#endif
+
+#include "log.h"
+#include "caps.h"
+
+void pa_drop_root(void) {
+    if (getuid() != 0 && geteuid() == 0) {
+        pa_log(__FILE__": Started SUID root, dropping root rights.\n");
+        setuid(getuid());
+        seteuid(getuid());
+    }
+}
+
+#ifdef HAVE_SYS_CAPABILITY_H
+int pa_limit_caps(void) {
+    int r = -1;
+    cap_t caps;
+    cap_value_t nice_cap = CAP_SYS_NICE;
+
+    caps = cap_init();
+    assert(caps);
+
+    cap_clear(caps);
+    cap_set_flag(caps, CAP_EFFECTIVE, 1, &nice_cap, CAP_SET);
+    cap_set_flag(caps, CAP_PERMITTED, 1, &nice_cap, CAP_SET);
+
+    if (cap_set_proc(caps) < 0)
+        goto fail;
+
+    pa_log(__FILE__": Started SUID root, capabilities limited.\n");
+
+    r = 0;
+
+fail:
+    cap_free (caps);
+    
+    return r;
+}
+
+int pa_drop_caps(void) {
+    cap_t caps;
+    int r = -1;
+
+    caps = cap_init();
+    assert(caps);
+
+    cap_clear(caps);
+
+    if (cap_set_proc(caps) < 0)
+        goto fail;
+
+    pa_drop_root();
+    
+    r = 0;
+
+fail:
+    cap_free (caps);
+    
+    return r;
+}
+
+#else
+
+int pa_limit_caps(void) {
+    return 0;
+}
+
+int pa_drop_caps(void) {
+    pa_drop_root();
+    return 0;
+}
+
+#endif
+