From: Eric Paris Date: Thu, 2 Dec 2010 21:13:40 +0000 (-0500) Subject: SELinux: do not compute transition labels on mountpoint labeled filesystems X-Git-Tag: v2.6.36.4~24 X-Git-Url: https://git.kernelconcepts.de/?p=karo-tx-linux.git;a=commitdiff_plain;h=1d91afd8b1854d363d88cf95dafeaffff6f8bb08 SELinux: do not compute transition labels on mountpoint labeled filesystems 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 Reviewed-by: Reviewed-by: James Morris Signed-off-by: Greg Kroah-Hartman --- diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 4796ddd4e721..a6238281186a 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -2529,7 +2529,10 @@ static int selinux_inode_init_security(struct inode *inode, struct inode *dir, 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);