X-Git-Url: https://git.ralfj.de/schsh.git/blobdiff_plain/6dfe0e9d89af3b03e9d199fd3ae086ab16aae77a..HEAD:/schsh?ds=sidebyside

diff --git a/schsh b/schsh
index e9464de..1a790bb 100755
--- a/schsh
+++ b/schsh
@@ -1,16 +1,39 @@
-#!/usr/bin/python
+#!/usr/bin/env python3
+import logging, logging.handlers
+import os, sys, shlex, pwd
 #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#
 # Configuration
 shell = None # set to "/bin/bash" or similar to allow shell access
-allowCommands = ["scp", "rsync", "/usr/lib/openssh/sftp-server"]
-commandPaths = ["/usr/bin", "/bin"]
+rrsync = "/usr/local/bin/schsh-rrsync" # path to the restricted rsync script - if available, it will be used to further restrict rsync access
+
+def allowSCP(run, runstr):
+	if len(run) != 3: return False
+	if run[0] != "scp": return False
+	if run[1] not in ("-f", "-t"): return False
+	if run[2].startswith('-'): return False
+	run[0] = "/usr/bin/scp"
+	return True
+
+def allowRSync(run, runstr):
+	if len(run) < 3: return False
+	if run[0] != "rsync": return False
+	if run[1] != "--server": return False
+	if rrsync is None:
+		# rrsync is not available, let's hope this is enough protection
+		run[0] = "/usr/bin/rsync"
+		return True
+	run[:] = [rrsync, "/", runstr] # allow access to the entire chroot
+	return True
+
+def allowSFTP(run, runstr):
+	return runstr == "/usr/lib/openssh/sftp-server"
+
+allowCommands = [allowSCP, allowRSync, allowSFTP]
 
 # END of Configuration
 #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#
 # DO NOT TOUCH ANYTHING BELOW THIS LINE
 
-import logging, logging.handlers
-import os, sys, shlex, pwd
 
 logger = logging.getLogger("schsh")
 logger.setLevel(logging.INFO)
@@ -27,32 +50,27 @@ def logquit(msg):
 	log(msg, logging.ERROR)
 	sys.exit(1)
 
-def addPath(prog):
-	if prog.startswith("/"):
-		return prog
-	# look for it in the paths
-	for path in commandPaths:
-		fullprog = os.path.join(path, prog)
-		if os.path.exists(fullprog):
-			return fullprog
-	return None
+def commandAllowed(run, runstr):
+	for allowed in allowCommands:
+		if allowed(run, runstr):
+			return True
+	return False
 
 # parse arguments
 run = []
 if len(sys.argv) == 1:
 	if shell is None:
-		print "No shell for you!"
+		print("No shell for you!")
 		logquit("Shell access not allowed")
 	else:
 		run = [shell]
 elif len(sys.argv) == 3 and sys.argv[1] == "-c":
 	# check if the command is allowed, and add path
 	run = shlex.split(sys.argv[2])
-	if len(run) > 0 and run[0] in allowCommands:
-		run[0] = addPath(run[0])
-		log("Running '"+str(run)+"'")
+	if commandAllowed(run, sys.argv[2]): # this may change run, but that's okay
+		log("Running "+str(run))
 	else:
-		print "You are not allowed to run this command."
+		print("You are not allowed to run this command.")
 		logquit("Attempt to run invalid command '"+sys.argv[2]+"'")
 else:
 	logquit("Invalid arguments for schsh: "+str(sys.argv))