Category
Security
Release Phase
Resolved
Bug Id
6848431
ProductSolaris 10 Operating System
OpenSolaris
Date of Resolved Release14-Oct-2009
A Security Vulnerability in the ZFS Filesystem May Allow An Unprivileged User to Take Ownership of Files Belonging to Another User
1. Impact
A security vulnerability in the ZFS file system in OpenSolaris and
Solaris 10 systems with patches 137137-09 (SPARC) or 137138-09 (x86)
installed may allow a local unprivileged user with the
'file_chown_self' privilege to take ownership of files belonging to
another user.
2. Contributing Factors
This issue can occur in the following releases:
SPARC Platform
- Solaris 10 with patch 137137-09 and without patch 141444-09
- OpenSolaris based upon builds snv_100 through snv_117
x86 Platform
- Solaris 10 with patch 137138-09 and without patch 141445-09
- OpenSolaris based upon builds snv_100 through snv_117
Notes:
1. Solaris 8 and 9 are not impacted by this issue.
2. OpenSolaris distributions may include additional bug fixes above and
beyond the build from which it was derived. The base build can be
derived as follows:
$ uname -v
snv_86
3. This issue only affects systems with ZFS file systems where local users
have been granted the {PRIV_FILE_CHOWN_SELF} (see chown(2)) privilege
which allows them to modify ownership of files where the ownership
matches the user's current effective user ID. If the default operating
system configuration option '{_POSIX_CHOWN_RESTRICTED}' has been
disabled then the 'file_chown_self' privilege is asserted in the
inheritable set of all processes unless overridden by policy.conf(4) or
user_attr(4).
To determine if a system is using ZFS, the following command can be run:
$ zfs list
If there are any pools listed, then ZFS is being used.
To determine if a user has been given the privilege to give away ownership of a file, the following command can be run:
$ ppriv <pid> | grep "file_chown_self" || echo "User not authorized give away ownership of files"
E: basic,dtrace_kernel,dtrace_proc,dtrace_user,file_chown_self,proc_owner
I: basic,dtrace_kernel,dtrace_proc,dtrace_user,file_chown_self,proc_owner
P: basic,dtrace_kernel,dtrace_proc,dtrace_user,file_chown_self,proc_owner
and then check if the output lists 'file_chown_self'.
To determine if all users system wide have been given the privilege to
give away ownership of a file, the following command can be run:
$ grep "set rstchown=0" /etc/system && echo "All users have privilege to give away ownership of a file"
All users have privilege to give away ownership of a file
3. Symptoms
There are no predictable symptoms that would indicate the described
vulnerability has been exploited.
4. Workaround
There is no workaround for this issue. Please see the Resolution
section below.
5. Resolution
This issue is addressed in the following releases:
SPARC Platform
- Solaris 10 with patch 141444-09 or later
- OpenSolaris based upon builds snv_118 or later
x86 Platform
- Solaris 10 with patch 141445-09 or later
- OpenSolaris based upon builds snv_118 or later
For
more information on
Security Sun Alerts, see 1009886.1.
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notification is being provided to you on
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Copyright 2000-2009 Sun
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Inc., 4150 Network Circle, Santa
Clara, CA 95054 U.S.A. All rights reserved.References
141444-09
141445-09
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