Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security

Pull security subsystem update from James Morris:
 "Just some minor updates across the subsystem"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  ima: eliminate passing d_name.name to process_measurement()
  TPM: Retry SaveState command in suspend path
  tpm/tpm_i2c_infineon: Add small comment about return value of __i2c_transfer
  tpm/tpm_i2c_infineon.c: Add OF attributes type and name to the of_device_id table entries
  tpm_i2c_stm_st33: Remove duplicate inclusion of header files
  tpm: Add support for new Infineon I2C TPM (SLB 9645 TT 1.2 I2C)
  char/tpm: Convert struct i2c_msg initialization to C99 format
  drivers/char/tpm/tpm_ppi: use strlcpy instead of strncpy
  tpm/tpm_i2c_stm_st33: formatting and white space changes
  Smack: include magic.h in smackfs.c
  selinux: make security_sb_clone_mnt_opts return an error on context mismatch
  seccomp: allow BPF_XOR based ALU instructions.
  Fix NULL pointer dereference in smack_inode_unlink() and smack_inode_rmdir()
  Smack: add support for modification of existing rules
  smack: SMACK_MAGIC to include/uapi/linux/magic.h
  Smack: add missing support for transmute bit in smack_str_from_perm()
  Smack: prevent revoke-subject from failing when unseen label is written to it
  tomoyo: use DEFINE_SRCU() to define tomoyo_ss
  tomoyo: use DEFINE_SRCU() to define tomoyo_ss

1 files changed, 35 insertions, 4 deletions

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 7171a957b933..feb2f42c5a07 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -751,7 +751,37 @@ out_double_mount:
         goto out;
 }
 
-static void selinux_sb_clone_mnt_opts(const struct super_block *oldsb,
+static int selinux_cmp_sb_context(const struct super_block *oldsb,
+                                    const struct super_block *newsb)
+{
+        struct superblock_security_struct *old = oldsb->s_security;
+        struct superblock_security_struct *new = newsb->s_security;
+        char oldflags = old->flags & SE_MNTMASK;
+        char newflags = new->flags & SE_MNTMASK;
+
+        if (oldflags != newflags)
+                goto mismatch;
+        if ((oldflags & FSCONTEXT_MNT) && old->sid != new->sid)
+                goto mismatch;
+        if ((oldflags & CONTEXT_MNT) && old->mntpoint_sid != new->mntpoint_sid)
+                goto mismatch;
+        if ((oldflags & DEFCONTEXT_MNT) && old->def_sid != new->def_sid)
+                goto mismatch;
+        if (oldflags & ROOTCONTEXT_MNT) {
+                struct inode_security_struct *oldroot = oldsb->s_root->d_inode->i_security;
+                struct inode_security_struct *newroot = newsb->s_root->d_inode->i_security;
+                if (oldroot->sid != newroot->sid)
+                        goto mismatch;
+        }
+        return 0;
+mismatch:
+        printk(KERN_WARNING "SELinux: mount invalid.  Same superblock, "
+                            "different security settings for (dev %s, "
+                            "type %s)\n", newsb->s_id, newsb->s_type->name);
+        return -EBUSY;
+}
+
+static int selinux_sb_clone_mnt_opts(const struct super_block *oldsb,
                                         struct super_block *newsb)
 {
         const struct superblock_security_struct *oldsbsec = oldsb->s_security;
@@ -766,14 +796,14 @@ static void selinux_sb_clone_mnt_opts(const struct super_block *oldsb,
          * mount options.  thus we can safely deal with this superblock later
          */
         if (!ss_initialized)
-                return;
+                return 0;
 
         /* how can we clone if the old one wasn't set up?? */
         BUG_ON(!(oldsbsec->flags & SE_SBINITIALIZED));
 
-        /* if fs is reusing a sb, just let its options stand... */
+        /* if fs is reusing a sb, make sure that the contexts match */
         if (newsbsec->flags & SE_SBINITIALIZED)
-                return;
+                return selinux_cmp_sb_context(oldsb, newsb);
 
         mutex_lock(&newsbsec->lock);
 
@@ -806,6 +836,7 @@ static void selinux_sb_clone_mnt_opts(const struct super_block *oldsb,
 
         sb_finish_set_opts(newsb);
         mutex_unlock(&newsbsec->lock);
+        return 0;
 }
 
 static int selinux_parse_opts_str(char *options,