Revert "selinux: consider filesystem subtype in policies"

This reverts commit 102aefdda4d8275ce7d7100bc16c88c74272b260.

Tom London reports that it causes sync() to hang on Fedora rawhide:

  https://bugzilla.redhat.com/show_bug.cgi?id=1033965

and Josh Boyer bisected it down to this commit.  Reverting the commit in
the rawhide kernel fixes the problem.

Eric Paris root-caused it to incorrect subtype matching in that commit
breaking fuse, and has a tentative patch, but by now we're better off
retrying this in 3.14 rather than playing with it any more.

Reported-by: Tom London <selinux@gmail.com>
Bisected-by: Josh Boyer <jwboyer@fedoraproject.org>
Acked-by: Eric Paris <eparis@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: Anand Avati <avati@redhat.com>
Cc: Paul Moore <paul@paul-moore.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 22 insertions, 60 deletions

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 794c3ca49eac..98b1caa1c1d3 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -95,10 +95,6 @@
 #include "audit.h"
 #include "avc_ss.h"
 
-#define SB_TYPE_FMT "%s%s%s"
-#define SB_SUBTYPE(sb) (sb->s_subtype && sb->s_subtype[0])
-#define SB_TYPE_ARGS(sb) sb->s_type->name, SB_SUBTYPE(sb) ? "." : "", SB_SUBTYPE(sb) ? sb->s_subtype : ""
-
 extern struct security_operations *security_ops;
 
 /* SECMARK reference count */
@@ -413,8 +409,8 @@ static int sb_finish_set_opts(struct super_block *sb)
                    the first boot of the SELinux kernel before we have
                    assigned xattr values to the filesystem. */
                 if (!root_inode->i_op->getxattr) {
-                        printk(KERN_WARNING "SELinux: (dev %s, type "SB_TYPE_FMT") has no "
-                               "xattr support\n", sb->s_id, SB_TYPE_ARGS(sb));
+                        printk(KERN_WARNING "SELinux: (dev %s, type %s) has no "
+                               "xattr support\n", sb->s_id, sb->s_type->name);
                         rc = -EOPNOTSUPP;
                         goto out;
                 }
@@ -422,22 +418,22 @@ static int sb_finish_set_opts(struct super_block *sb)
                 if (rc < 0 && rc != -ENODATA) {
                         if (rc == -EOPNOTSUPP)
                                 printk(KERN_WARNING "SELinux: (dev %s, type "
-                                       SB_TYPE_FMT") has no security xattr handler\n",
-                                       sb->s_id, SB_TYPE_ARGS(sb));
+                                       "%s) has no security xattr handler\n",
+                                       sb->s_id, sb->s_type->name);
                         else
                                 printk(KERN_WARNING "SELinux: (dev %s, type "
-                                       SB_TYPE_FMT") getxattr errno %d\n", sb->s_id,
-                                       SB_TYPE_ARGS(sb), -rc);
+                                       "%s) getxattr errno %d\n", sb->s_id,
+                                       sb->s_type->name, -rc);
                         goto out;
                 }
         }
 
         if (sbsec->behavior > ARRAY_SIZE(labeling_behaviors))
-                printk(KERN_ERR "SELinux: initialized (dev %s, type "SB_TYPE_FMT"), unknown behavior\n",
-                       sb->s_id, SB_TYPE_ARGS(sb));
+                printk(KERN_ERR "SELinux: initialized (dev %s, type %s), unknown behavior\n",
+                       sb->s_id, sb->s_type->name);
         else
-                printk(KERN_DEBUG "SELinux: initialized (dev %s, type "SB_TYPE_FMT"), %s\n",
-                       sb->s_id, SB_TYPE_ARGS(sb),
+                printk(KERN_DEBUG "SELinux: initialized (dev %s, type %s), %s\n",
+                       sb->s_id, sb->s_type->name,
                        labeling_behaviors[sbsec->behavior-1]);
 
         sbsec->flags |= SE_SBINITIALIZED;
@@ -600,6 +596,7 @@ static int selinux_set_mnt_opts(struct super_block *sb,
         const struct cred *cred = current_cred();
         int rc = 0, i;
         struct superblock_security_struct *sbsec = sb->s_security;
+        const char *name = sb->s_type->name;
         struct inode *inode = sbsec->sb->s_root->d_inode;
         struct inode_security_struct *root_isec = inode->i_security;
         u32 fscontext_sid = 0, context_sid = 0, rootcontext_sid = 0;
@@ -658,8 +655,8 @@ static int selinux_set_mnt_opts(struct super_block *sb,
                                              strlen(mount_options[i]), &sid);
                 if (rc) {
                         printk(KERN_WARNING "SELinux: security_context_to_sid"
-                               "(%s) failed for (dev %s, type "SB_TYPE_FMT") errno=%d\n",
-                               mount_options[i], sb->s_id, SB_TYPE_ARGS(sb), rc);
+                               "(%s) failed for (dev %s, type %s) errno=%d\n",
+                               mount_options[i], sb->s_id, name, rc);
                         goto out;
                 }
                 switch (flags[i]) {
@@ -806,8 +803,7 @@ out:
 out_double_mount:
         rc = -EINVAL;
         printk(KERN_WARNING "SELinux: mount invalid.  Same superblock, different "
-               "security settings for (dev %s, type "SB_TYPE_FMT")\n", sb->s_id,
-               SB_TYPE_ARGS(sb));
+               "security settings for (dev %s, type %s)\n", sb->s_id, name);
         goto out;
 }
 
@@ -2480,8 +2476,8 @@ static int selinux_sb_remount(struct super_block *sb, void *data)
                 rc = security_context_to_sid(mount_options[i], len, &sid);
                 if (rc) {
                         printk(KERN_WARNING "SELinux: security_context_to_sid"
-                               "(%s) failed for (dev %s, type "SB_TYPE_FMT") errno=%d\n",
-                               mount_options[i], sb->s_id, SB_TYPE_ARGS(sb), rc);
+                               "(%s) failed for (dev %s, type %s) errno=%d\n",
+                               mount_options[i], sb->s_id, sb->s_type->name, rc);
                         goto out_free_opts;
                 }
                 rc = -EINVAL;
@@ -2519,8 +2515,8 @@ out_free_secdata:
         return rc;
 out_bad_option:
         printk(KERN_WARNING "SELinux: unable to change security options "
-               "during remount (dev %s, type "SB_TYPE_FMT")\n", sb->s_id,
-               SB_TYPE_ARGS(sb));
+               "during remount (dev %s, type=%s)\n", sb->s_id,
+               sb->s_type->name);
         goto out_free_opts;
 }
 
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index ee470a0b5c27..d106733ad987 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -2334,50 +2334,16 @@ int security_fs_use(struct super_block *sb)
         struct ocontext *c;
         struct superblock_security_struct *sbsec = sb->s_security;
         const char *fstype = sb->s_type->name;
-        const char *subtype = (sb->s_subtype && sb->s_subtype[0]) ? sb->s_subtype : NULL;
-        struct ocontext *base = NULL;
 
         read_lock(&policy_rwlock);
 
-        for (c = policydb.ocontexts[OCON_FSUSE]; c; c = c->next) {
-                char *sub;
-                int baselen;
-
-                baselen = strlen(fstype);
-
-                /* if base does not match, this is not the one */
-                if (strncmp(fstype, c->u.name, baselen))
-                        continue;
-
-                /* if there is no subtype, this is the one! */
-                if (!subtype)
-                        break;
-
-                /* skip past the base in this entry */
-                sub = c->u.name + baselen;
-
-                /* entry is only a base. save it. keep looking for subtype */
-                if (sub[0] == '\0') {
-                        base = c;
-                        continue;
-                }
-
-                /* entry is not followed by a subtype, so it is not a match */
-                if (sub[0] != '.')
-                        continue;
-
-                /* whew, we found a subtype of this fstype */
-                sub++; /* move past '.' */
-
-                /* exact match of fstype AND subtype */
-                if (!strcmp(subtype, sub))
+        c = policydb.ocontexts[OCON_FSUSE];
+        while (c) {
+                if (strcmp(fstype, c->u.name) == 0)
                         break;
+                c = c->next;
         }
 
-        /* in case we had found an fstype match but no subtype match */
-        if (!c)
-                c = base;
-
         if (c) {
                 sbsec->behavior = c->v.behavior;
                 if (!c->sid[0]) {