supported script execution for dhcp6relay (contributed by Bruno STEVANT)

1 files changed, 40 insertions, 0 deletions

diff --git a/common.c b/common.c
index 7b1ba4f..6c1c621 100644
--- a/common.c
+++ b/common.c
@@ -32,6 +32,7 @@
 #include <sys/socket.h>
 #include <sys/ioctl.h>
 #include <sys/queue.h>
+#include <sys/stat.h>
 #if TIME_WITH_SYS_TIME
 # include <sys/time.h>
 # include <time.h>
@@ -3339,3 +3340,42 @@ ifaddrconf(cmd, ifname, addr, plen, pltime, vltime)
 	close(s);
 	return (0);
 }
+
+int
+safefile(path)
+	const char *path;
+{
+	struct stat s;
+	uid_t myuid;
+
+	/* no setuid */
+	if (getuid() != geteuid()) {
+		dprintf(LOG_NOTICE, FNAME,
+		    "setuid'ed execution not allowed");
+		return (-1);
+	}
+
+	if (lstat(path, &s) != 0) {
+		dprintf(LOG_NOTICE, FNAME, "lstat failed: %s",
+		    strerror(errno));
+		return (-1);
+	}
+
+	/* the file must be owned by the running uid */
+	myuid = getuid();
+	if (s.st_uid != myuid) {
+		dprintf(LOG_NOTICE, FNAME, "%s has invalid owner uid", path);
+		return (-1);
+	}
+
+	switch (s.st_mode & S_IFMT) {
+	case S_IFREG:
+		break;
+	default:
+		dprintf(LOG_NOTICE, FNAME, "%s is an invalid file type 0x%o",
+		    path, (s.st_mode & S_IFMT));
+		return (-1);
+	}
+
+	return (0);
+}