| Date | Tue, 15 Feb 2011 16:14:45 -0800 | From | Greg KH <> | Subject | [228/272] SELinux: do not compute transition labels on mountpoint labeled filesystems |
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2.6.37-stable review patch. If anyone has any objections, please let us know.
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From: Eric Paris <eparis@redhat.com>
commit 415103f9932d45f7927f4b17e3a9a13834cdb9a1 upstream.
selinux_inode_init_security computes transitions sids even for filesystems that use mount point labeling. It shouldn't do that. It should just use the mount point label always and no matter what.
This causes 2 problems. 1) it makes file creation slower than it needs to be since we calculate the transition sid and 2) it allows files to be created with a different label than the mount point!
# id -Z staff_u:sysadm_r:sysadm_t:s0-s0:c0.c1023 # sesearch --type --class file --source sysadm_t --target tmp_t Found 1 semantic te rules: type_transition sysadm_t tmp_t : file user_tmp_t;
# mount -o loop,context="system_u:object_r:tmp_t:s0" /tmp/fs /mnt/tmp
# ls -lZ /mnt/tmp drwx------. root root system_u:object_r:tmp_t:s0 lost+found # touch /mnt/tmp/file1 # ls -lZ /mnt/tmp -rw-r--r--. root root staff_u:object_r:user_tmp_t:s0 file1 drwx------. root root system_u:object_r:tmp_t:s0 lost+found
Whoops, we have a mount point labeled filesystem tmp_t with a user_tmp_t labeled file!
Signed-off-by: Eric Paris <eparis@redhat.com> Reviewed-by: Reviewed-by: James Morris <jmorris@namei.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- security/selinux/hooks.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
--- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -2525,7 +2525,10 @@ static int selinux_inode_init_security(s sid = tsec->sid; newsid = tsec->create_sid; - if (!newsid || !(sbsec->flags & SE_SBLABELSUPP)) { + if ((sbsec->flags & SE_SBINITIALIZED) && + (sbsec->behavior == SECURITY_FS_USE_MNTPOINT)) + newsid = sbsec->mntpoint_sid; + else if (!newsid || !(sbsec->flags & SE_SBLABELSUPP)) { rc = security_transition_sid(sid, dsec->sid, inode_mode_to_security_class(inode->i_mode), &newsid);
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