User gets IOException when attempting to invoke a shell script from
Java. User can invoke the shell script from the Unix command prompt.


Believed cause:

User's primary group is not the same as the group of the shell script,
even though user is a member of that group.


Further info:

This problem occurs on Solaris 2.5.1 sparc and x86 hardware.


------------------------------------------------------------------------

$ ls -lagL ./test.sh
-rwxrwx--- 1 root t3proj 52 May 12 11:43 ./test.sh
$ ./test.sh
        id
uid=101(henryg) gid=10(staff)
        groups
staff sysadmin osecomms oselibs ship terse termsim ada bnalib bnautils bpoll t27 uts consult t3proj
 
        echo executing $0
executing ./test.sh
$ java exec test.sh
IOException: test.sh: cannot execute
$ uname -a
SunOS thredbo 5.5.1 Generic_103640-03 sun4m sparc SUNW,SPARCstation-10,SX
$

------------------------------------------------------------------------

Enclosures:

exec.class the class file
exec.java the java source file
test.sh the shell script


Name: nt126004 Date: 06/28/2002


FULL PRODUCT VERSION :
Java(TM) 2 SDK, Standard Edition
Version 1.4.1 Beta


FULL OPERATING SYSTEM VERSION :
glibc-2.1.92-14
Linux 2.2.16-22smp i686
Red Hat Linux release 7.0 (Guinness)

A DESCRIPTION OF THE PROBLEM :
When a java program is launched by root, cannot execute
external program (using Java's runtime class) owned by
another user/group without other's executable permission.

On linux system, root must be able to execute any program
that has at least an executable permission and that belong
to any group or user.

It should be the same for a java program launched by root
that wants to execute an external program.


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1.
# id
uid=0(root) gid=0(root) groups=0(root),1(bin),2(daemon),3
(sys),4(adm),6(disk),10(wheel)
# more TestRoot.java
public class TestRoot {
    public static void main(String[] args)
    {
try
{
String cmd = args[0];
Process p = Runtime.getRuntime().exec(cmd);
p.waitFor();
}
catch (Throwable t)
{
t.printStackTrace();
}
    }
}
# /usr/java/j2sdk1.4.1/bin/javac TestRoot.java
# ls -l /usr/bin/X11/xterm
-rwxr-xr-x 1 root root 200724 Aug 30
2000 /usr/bin/X11/xterm
# /usr/java/j2sdk1.4.1/bin/java TestRoot /usr/bin/X11/xterm

2.
# chown user1:group1 /usr/bin/X11/xterm
# chmod o-x /usr/bin/X11/xterm
# ls -l /usr/bin/X11/xterm
-rwxr-xr-- 1 user1 group1 200724 Aug 30
2000 /usr/bin/X11/xterm
# xterm

3.
# /usr/java/j2sdk1.4.1/bin/java TestRoot /usr/bin/X11/xterm
java.io.IOException:
java.io.IOException: /usr/bin/X11/xterm: cannot execute
at java.lang.UNIXProcess.<init>(UNIXProcess.java:143)
at java.lang.Runtime.execInternal(Native Method)
at java.lang.Runtime.exec(Runtime.java:566)
at java.lang.Runtime.exec(Runtime.java:428)
at java.lang.Runtime.exec(Runtime.java:364)
at java.lang.Runtime.exec(Runtime.java:326)
at TestRoot.main(TestRoot.java:7)


EXPECTED VERSUS ACTUAL BEHAVIOR :
1. First step compiling a small java program that execute
any command. When executing /usr/bin/X11/xterm from java
program, an xterm appears (note that by default xterm has
execution permission for root)

2. Now we change the owner and permissions
on /usr/bin/X11/xterm so that it doesn't belongs to root or
root's group, and so that other's executable permission is
disabled. When executing xterm from the prompt, an xterm
appears

3. Now we try to execute /usr/bin/X11/xterm from the java
program, an IOException occurs and obviously the xterm
doesn't appear. We think that it should have worked.

ERROR MESSAGES/STACK TRACES THAT OCCUR :
java.io.IOException: java.io.IOException: /usr/bin/X11/xterm: cannot execute
at java.lang.UNIXProcess.<init>(UNIXProcess.java:143)
at java.lang.Runtime.execInternal(Native Method)
at java.lang.Runtime.exec(Runtime.java:566)
at java.lang.Runtime.exec(Runtime.java:428)
at java.lang.Runtime.exec(Runtime.java:364)
at java.lang.Runtime.exec(Runtime.java:326)
at TestRoot.main(TestRoot.java:7)

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
# id
uid=0(root) gid=0(root) groups=0(root),1(bin),2(daemon),3(sys),4(adm),6(disk),10
(wheel)
# more TestRoot.java
public class TestRoot {
    public static void main(String[] args)
    {
try
{
String cmd = args[0];
Process p = Runtime.getRuntime().exec(cmd);
p.waitFor();
}
catch (Throwable t)
{
t.printStackTrace();
}
    }
}
# /usr/java/j2sdk1.4.1/bin/javac TestRoot.java
# ls -l /usr/bin/X11/xterm
-rwxr-xr-x 1 root root 200724 Aug 30 2000 /usr/bin/X11/xterm
# /usr/java/j2sdk1.4.1/bin/java TestRoot /usr/bin/X11/xterm
# chown user1:group1 /usr/bin/X11/xterm
# chmod o-x /usr/bin/X11/xterm
# ls -l /usr/bin/X11/xterm
-rwxr-xr-- 1 user1 group1 200724 Aug 30 2000 /usr/bin/X11/xterm
# xterm
# /usr/java/j2sdk1.4.1/bin/java TestRoot /usr/bin/X11/xterm
java.io.IOException: java.io.IOException: /usr/bin/X11/xterm: cannot execute
at java.lang.UNIXProcess.<init>(UNIXProcess.java:143)
at java.lang.Runtime.execInternal(Native Method)
at java.lang.Runtime.exec(Runtime.java:566)
at java.lang.Runtime.exec(Runtime.java:428)
at java.lang.Runtime.exec(Runtime.java:364)
at java.lang.Runtime.exec(Runtime.java:326)
---------- END SOURCE ----------

CUSTOMER WORKAROUND :
I don't have any workaround to provide. The only solution
is to set grants and ownership so that the "root" user can
launch the expected program as if it was a normal user.
(Review ID: 158634)
======================================================================