17

I installed Debian in VirtualBox (for various experiments which usually broke my system) and tried to launch the VirtualBox guest addon script. I logged in as root and tried to launch autorun.sh, but I got «Permission denied». ls -l shows that the script have an executable rights.

Sorry, that I can't copy the output -- VirtualBox absolutely have no use without the addon, as neither a shared directory, nor a shared clipboard works. But just for you to be sure, I copied the rights by hands:

#ls -l ./autorun.sh
-r-xr-xr-x 1 root root 6966 Mar 26 13:56 ./autorun.sh

At first I thought that it may be that the script executes something that gave the error. I tried to replace /bin/sh with something like #/pathtorealsh/sh -xv, but I got no output — it seems the script can't even be executed.

I have not even an idea what could cause it.

  • 2
    Looks like it should work. Try running it with bash explicitly: `bash -x ./autorun.sh". Maybe this will give an additional clue. – nobar Aug 24 '14 at 6:08
  • 2
    What is output of mount | grep noexec? – cuonglm Aug 24 '14 at 6:12
  • 1
    @Gnouc, you're right, the mounted «cdrom» have the noexec set. Probably you may post it as an answer; meanwhile I am trying to remount it with an exec rights. Hm, I didn't even knew that the filesystem could have such an attribute. – Hi-Angel Aug 24 '14 at 6:16
  • And if you try to run it via going sh ./autorun.sh what happens? – infixed Apr 5 '16 at 17:34
27

Maybe your file system is mounted with noexec option set, so you can not run any executable files. From mount documentation:

noexec

Do not allow direct execution of any binaries on the mounted filesystem. (Until recently it was possible to run binaries anyway using a command like /lib/ld*.so /mnt/binary. This trick fails since Linux 2.4.25 / 2.6.0.)

Try:

mount | grep noexec

Then check if your file system is listed in output.

If yes, you can solve this problem, by re-mounting file system with exec option:

mount -o remount,exec filesystem
  • That didn't work for me. I had to unmount and then remount normally. Then it worked fine. – datakid Jun 23 '16 at 4:01
  • @datakid: What is your fs? – cuonglm Jun 23 '16 at 4:14
  • I am having this issue with debian 9, some files are permission denied if the scripts is running as root, but it identify as root... like a windows behavior, if i remove & the script worked! =[ – Luciano Andress Martini Dec 14 '17 at 13:07
  • I was getting a very strange message, which turned out to be because of noexec: "sh: 75: script.sh: Permission denied" – tmm1 Oct 3 '18 at 21:03
2

bash -x ./filename.filetype should work. It worked for me when I got permission denied as a root user.

  • No, as in the end the problem turned out to be the noexec mount option, this won't work, because there could be more files that have to be executed; i.e. the filename.filetype would gasp trying to execute other files from the same filesystem. You can easily check it with a simplified test: create a two line script which prints "hello", then just calls himself again, but do not set executable rights. If you execute it with -x, it would print "hello", but then the recursive call line would trigger an error. – Hi-Angel Apr 6 '16 at 4:33
1

My solution to this problem is to use source. I was on a storage volume of very important data. This volume is mounted as noexec. I have a simple shell script that is executable but got permission problem.

./fixsamplesheet.sh # this guy is executable
-bash: ./fixsamplesheet.sh: Permission denied

source fixsamplesheet.sh # worked fine

Only tested on my Ubuntu.

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