Bug 1665

Summary: /dev/zero has incorrect permissions
Product: [Retired] Red Hat Linux Reporter: jmegq
Component: devAssignee: Michael K. Johnson <johnsonm>
Severity: medium Docs Contact:
Priority: medium    
Version: 5.2   
Target Milestone: ---   
Target Release: ---   
Hardware: i386   
OS: Linux   
Fixed In Version: Doc Type: Bug Fix
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Clone Of: Environment:
Last Closed: 1999-03-23 20:13:57 UTC Type: ---
Regression: --- Mount Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description jmegq 1999-03-22 09:25:33 UTC
/dev/zero should be world writable, but is not.
This is true of the Rawhide and Starbuck releases as well
as the 5.2 release, and presumably other releases.

The manpage for /dev/null and /dev/zero ("man null") say
that both devices should be world-writable, but only
/dev/null is. (/dev/zero is owner and group writable only).

Strangely, MAKEDEV seems to want to make both devices 0666,
but I haven't verified that it does so.

The problem shows itself with JDK1.2pre-v1:
JDK1.2 uses /dev/zero internally to throw stuff away, and
expects it to be world-writable; I imagine this may be
confusing some people who are trying to use it.

e.g. (on starbuck):
    % setenv THREADS_FLAG green
    % java -Djava.compiler= -version
    devzero: Permission denied


Comment 1 David Lawrence 1999-03-23 19:10:59 UTC
I have verified this to be true in the test lab. It is being assigned
to a developer.

Comment 2 Michael K. Johnson 1999-03-23 20:13:59 UTC
This was originally changed because someone voiced a security-related
concern.  That concern (that /dev/zero does not erase the buffer
passed to it) is not a legitimate concern and while programs really
should use /dev/null to throw things away, I'll change the dev
package to make /dev/zero world writable in dev-2.6.4