1 files changed, 99 insertions, 0 deletions
diff --git a/src/daemon/caps.c b/src/daemon/caps.c
new file mode 100644
index 0000000..fd135c0
--- /dev/null
+++ b/src/daemon/caps.c
@@ -0,0 +1,99 @@
+/***
+  This file is part of PulseAudio.
+
+  Copyright 2004-2006 Lennart Poettering
+  Copyright 2006 Pierre Ossman <ossman@cendio.se> for Cendio AB
+
+  PulseAudio is free software; you can redistribute it and/or modify
+  it under the terms of the GNU Lesser General Public License as published
+  by the Free Software Foundation; either version 2.1 of the License,
+  or (at your option) any later version.
+
+  PulseAudio 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 Lesser General Public License
+  along with PulseAudio; if not, see <http://www.gnu.org/licenses/>.
+***/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <unistd.h>
+#include <errno.h>
+#include <sys/types.h>
+
+#include <pulsecore/i18n.h>
+#include <pulsecore/macro.h>
+#include <pulsecore/log.h>
+
+#ifdef HAVE_SYS_CAPABILITY_H
+#include <sys/capability.h>
+#endif
+
+#include "caps.h"
+
+/* Glibc <= 2.2 has broken unistd.h */
+#if defined(__linux__) && (__GLIBC__ <= 2 && __GLIBC_MINOR__ <= 2)
+int setresgid(gid_t r, gid_t e, gid_t s);
+int setresuid(uid_t r, uid_t e, uid_t s);
+#endif
+
+/* Drop root rights when called SUID root */
+void pa_drop_root(void) {
+
+#ifdef HAVE_GETUID
+    uid_t uid;
+    gid_t gid;
+
+    pa_log_debug("Cleaning up privileges.");
+    uid = getuid();
+    gid = getgid();
+
+#if defined(HAVE_SETRESUID)
+    pa_assert_se(setresuid(uid, uid, uid) >= 0);
+    pa_assert_se(setresgid(gid, gid, gid) >= 0);
+#elif defined(HAVE_SETREUID)
+    pa_assert_se(setreuid(uid, uid) >= 0);
+    pa_assert_se(setregid(gid, gid) >= 0);
+#else
+    pa_assert_se(setuid(uid) >= 0);
+    pa_assert_se(seteuid(uid) >= 0);
+    pa_assert_se(setgid(gid) >= 0);
+    pa_assert_se(setegid(gid) >= 0);
+#endif
+
+    pa_assert_se(getuid() == uid);
+    pa_assert_se(geteuid() == uid);
+    pa_assert_se(getgid() == gid);
+    pa_assert_se(getegid() == gid);
+
+    if (uid != 0)
+        pa_drop_caps();
+#endif
+}
+
+void pa_drop_caps(void) {
+#ifdef HAVE_SYS_CAPABILITY_H
+#if defined(__linux__)
+    cap_t caps;
+    pa_assert_se(caps = cap_init());
+    pa_assert_se(cap_clear(caps) == 0);
+    pa_assert_se(cap_set_proc(caps) == 0);
+    pa_assert_se(cap_free(caps) == 0);
+#elif defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
+    /* FreeBSD doesn't have this functionality, even though sys/capability.h is
+     * available. See https://bugs.freedesktop.org/show_bug.cgi?id=72580 */
+    pa_log_warn("FreeBSD cannot drop extra capabilities, implementation needed.");
+#else
+#error "Don't know how to do capabilities on your system.  Please send a patch."
+#endif /* __linux__ */
+#else /* HAVE_SYS_CAPABILITY_H */
+    pa_log_warn("Normally all extra capabilities would be dropped now, but "
+                "that's impossible because PulseAudio was built without "
+                "capabilities support.");
+#endif
+}