better filtering

[schsh.git] / schsh

diff --git a/schsh b/schsh
index 270691e3b77844a1acc94086b985d0f848e7e100..b433a19ab1034af1c16ff8f36aea21fd7067ac2a 100755 (executable)
--- a/schsh
+++ b/schsh
@@ -2,7 +2,24 @@
 #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#
 # Configuration
 shell = None # set to "/bin/bash" or similar to allow shell access
-allowCommands = ["scp", "rsync", "/usr/lib/openssh/sftp-server"]
+
+def allowSCP(run):
+       if len(run) != 3: return False
+       if run[0] != "scp": return False
+       if run[1] not in ("-f", "-t"): return False
+       return True
+
+def allowRSync(run):
+       if len(run) < 3: return False
+       if run[0] != "rsync": return False
+       if run[1] != "--server": return False
+       return True
+
+def allowSFTP(run):
+       if len(run) != 1: return False
+       return run[0] == "/usr/lib/openssh/sftp-server"
+
+allowCommands = [allowSCP, allowRSync, allowSFTP]
 commandPaths = ["/usr/bin", "/bin"]
 
 # END of Configuration
@@ -27,6 +44,12 @@ def logquit(msg):
        log(msg, logging.ERROR)
        sys.exit(1)
 
+def commandAllowed(run):
+       for allowed in allowCommands:
+               if allowed(run):
+                       return True
+       return False
+
 def addPath(prog):
        if prog.startswith("/"):
                return prog
@@ -48,7 +71,7 @@ if len(sys.argv) == 1:
 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:
+       if commandAllowed(run):
                run[0] = addPath(run[0])
                log("Running '"+str(run)+"'")
        else:
@@ -58,4 +81,4 @@ else:
        logquit("Invalid arguments for schsh: "+str(sys.argv))
 
 assert len(run) > 0
-os.execl("/usr/bin/schroot", "/usr/bin/schroot", "-c", "user-"+get_username(), "-d", "/data", "--", *run)
+os.execl("/usr/bin/schroot", "/usr/bin/schroot", "-c", "schsh-"+get_username(), "-d", "/data", "--", *run)