From: Eric Paris <eparis@parisplace.org>
Date: Fri, 14 Jul 2006 07:24:33 +0000 (-0700)
Subject: [PATCH] Fix security check for joint context= and fscontext= mount options
X-Git-Tag: v2.6.18-rc2~26
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b04ea3cebf79d6808632808072f276dbc98aaf01;p=linux-2.6

[PATCH] Fix security check for joint context= and fscontext= mount options

After some discussion on the actual meaning of the filesystem class
security check in try context mount it was determined that the checks for
the context= mount options were not correct if fscontext mount option had
already been used.

When labeling the superblock we should be checking relabel_from and
relabel_to.  But if the superblock has already been labeled (with
fscontext) then context= is actually labeling the inodes, and so we should
be checking relabel_from and associate.  This patch fixes which checks are
called depending on the mount options.

Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: James Morris <jmorris@namei.org>
Cc: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 2e8b4dfcbc..a91c961ba3 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -523,12 +523,16 @@ static int try_context_mount(struct super_block *sb, void *data)
 			goto out_free;
 		}
 
-		rc = may_context_mount_sb_relabel(sid, sbsec, tsec);
-		if (rc)
-			goto out_free;
-
-		if (!fscontext)
+		if (!fscontext) {
+			rc = may_context_mount_sb_relabel(sid, sbsec, tsec);
+			if (rc)
+				goto out_free;
 			sbsec->sid = sid;
+		} else {
+			rc = may_context_mount_inode_relabel(sid, sbsec, tsec);
+			if (rc)
+				goto out_free;
+		}
 		sbsec->mntpoint_sid = sid;
 
 		sbsec->behavior = SECURITY_FS_USE_MNTPOINT;