From 8e6c96935fcc1ed3dbebc96fddfef3f2f2395afc Mon Sep 17 00:00:00 2001 From: Lucian Adrian Grijincu Date: Tue, 1 Feb 2011 18:42:22 +0200 Subject: security/selinux: fix /proc/sys/ labeling This fixes an old (2007) selinux regression: filesystem labeling for /proc/sys returned -r--r--r-- unknown /proc/sys/fs/file-nr instead of -r--r--r-- system_u:object_r:sysctl_fs_t:s0 /proc/sys/fs/file-nr Events that lead to breaking of /proc/sys/ selinux labeling: 1) sysctl was reimplemented to route all calls through /proc/sys/ commit 77b14db502cb85a031fe8fde6c85d52f3e0acb63 [PATCH] sysctl: reimplement the sysctl proc support 2) proc_dir_entry was removed from ctl_table: commit 3fbfa98112fc3962c416452a0baf2214381030e6 [PATCH] sysctl: remove the proc_dir_entry member for the sysctl tables 3) selinux still walked the proc_dir_entry tree to apply labeling. Because ctl_tables don't have a proc_dir_entry, we did not label /proc/sys/ inodes any more. To achieve this the /proc/sys/ inodes were marked private and private inodes were ignored by selinux. commit bbaca6c2e7ef0f663bc31be4dad7cf530f6c4962 [PATCH] selinux: enhance selinux to always ignore private inodes commit 86a71dbd3e81e8870d0f0e56b87875f57e58222b [PATCH] sysctl: hide the sysctl proc inodes from selinux Access control checks have been done by means of a special sysctl hook that was called for read/write accesses to any /proc/sys/ entry. We don't have to do this because, instead of walking the proc_dir_entry tree we can walk the dentry tree (as done in this patch). With this patch: * we don't mark /proc/sys/ inodes as private * we don't need the sysclt security hook * we walk the dentry tree to find the path to the inode. We have to strip the PID in /proc/PID/ entries that have a proc_dir_entry because selinux does not know how to label paths like '/1/net/rpc/nfsd.fh' (and defaults to 'proc_t' labeling). Selinux does know of '/net/rpc/nfsd.fh' (and applies the 'sysctl_rpc_t' label). PID stripping from the path was done implicitly in the previous code because the proc_dir_entry tree had the root in '/net' in the example from above. The dentry tree has the root in '/1'. Signed-off-by: Eric W. Biederman Signed-off-by: Lucian Adrian Grijincu Signed-off-by: Eric Paris --- fs/proc/proc_sysctl.c | 1 - 1 file changed, 1 deletion(-) (limited to 'fs/proc') diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index 09a1f92a34ef..fb707e018a81 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -32,7 +32,6 @@ static struct inode *proc_sys_make_inode(struct super_block *sb, ei->sysctl_entry = table; inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; - inode->i_flags |= S_PRIVATE; /* tell selinux to ignore this inode */ inode->i_mode = table->mode; if (!table->child) { inode->i_mode |= S_IFREG; -- cgit v1.2.1