1 files changed, 22 insertions, 36 deletions

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 92f909a2e8f7..eaea837d89d1 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -358,7 +358,7 @@ static void inode_free_security(struct inode *inode)
 
 	if (!isec)
 		return;
-	sbsec = inode->i_sb->s_security;
+	sbsec = selinux_superblock(inode->i_sb);
 	/*
 	 * As not all inode security structures are in a list, we check for
 	 * empty list outside of the lock to make sure that we won't waste
@@ -376,13 +376,6 @@ static void inode_free_security(struct inode *inode)
 	}
 }
 
-static void superblock_free_security(struct super_block *sb)
-{
-	struct superblock_security_struct *sbsec = sb->s_security;
-	sb->s_security = NULL;
-	kfree(sbsec);
-}
-
 struct selinux_mnt_opts {
 	const char *fscontext, *context, *rootcontext, *defcontext;
 };
@@ -494,7 +487,7 @@ static int selinux_is_genfs_special_handling(struct super_block *sb)
 
 static int selinux_is_sblabel_mnt(struct super_block *sb)
 {
-	struct superblock_security_struct *sbsec = sb->s_security;
+	struct superblock_security_struct *sbsec = selinux_superblock(sb);
 
 	/*
 	 * IMPORTANT: Double-check logic in this function when adding a new
@@ -571,7 +564,7 @@ fallback:
 
 static int sb_finish_set_opts(struct super_block *sb)
 {
-	struct superblock_security_struct *sbsec = sb->s_security;
+	struct superblock_security_struct *sbsec = selinux_superblock(sb);
 	struct dentry *root = sb->s_root;
 	struct inode *root_inode = d_backing_inode(root);
 	int rc = 0;
@@ -662,7 +655,7 @@ static int selinux_set_mnt_opts(struct super_block *sb,
 				unsigned long *set_kern_flags)
 {
 	const struct cred *cred = current_cred();
-	struct superblock_security_struct *sbsec = sb->s_security;
+	struct superblock_security_struct *sbsec = selinux_superblock(sb);
 	struct dentry *root = sb->s_root;
 	struct selinux_mnt_opts *opts = mnt_opts;
 	struct inode_security_struct *root_isec;
@@ -900,8 +893,8 @@ out_double_mount:
 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;
+	struct superblock_security_struct *old = selinux_superblock(oldsb);
+	struct superblock_security_struct *new = selinux_superblock(newsb);
 	char oldflags = old->flags & SE_MNTMASK;
 	char newflags = new->flags & SE_MNTMASK;
 
@@ -933,8 +926,9 @@ static int selinux_sb_clone_mnt_opts(const struct super_block *oldsb,
 					unsigned long *set_kern_flags)
 {
 	int rc = 0;
-	const struct superblock_security_struct *oldsbsec = oldsb->s_security;
-	struct superblock_security_struct *newsbsec = newsb->s_security;
+	const struct superblock_security_struct *oldsbsec =
+						selinux_superblock(oldsb);
+	struct superblock_security_struct *newsbsec = selinux_superblock(newsb);
 
 	int set_fscontext =	(oldsbsec->flags & FSCONTEXT_MNT);
 	int set_context =	(oldsbsec->flags & CONTEXT_MNT);
@@ -1113,7 +1107,7 @@ static int show_sid(struct seq_file *m, u32 sid)
 
 static int selinux_sb_show_options(struct seq_file *m, struct super_block *sb)
 {
-	struct superblock_security_struct *sbsec = sb->s_security;
+	struct superblock_security_struct *sbsec = selinux_superblock(sb);
 	int rc;
 
 	if (!(sbsec->flags & SE_SBINITIALIZED))
@@ -1464,7 +1458,7 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
 	if (isec->sclass == SECCLASS_FILE)
 		isec->sclass = inode_mode_to_security_class(inode->i_mode);
 
-	sbsec = inode->i_sb->s_security;
+	sbsec = selinux_superblock(inode->i_sb);
 	if (!(sbsec->flags & SE_SBINITIALIZED)) {
 		/* Defer initialization until selinux_complete_init,
 		   after the initial policy is loaded and the security
@@ -1815,7 +1809,8 @@ selinux_determine_inode_label(const struct task_security_struct *tsec,
 				 const struct qstr *name, u16 tclass,
 				 u32 *_new_isid)
 {
-	const struct superblock_security_struct *sbsec = dir->i_sb->s_security;
+	const struct superblock_security_struct *sbsec =
+						selinux_superblock(dir->i_sb);
 
 	if ((sbsec->flags & SE_SBINITIALIZED) &&
 	    (sbsec->behavior == SECURITY_FS_USE_MNTPOINT)) {
@@ -1846,7 +1841,7 @@ static int may_create(struct inode *dir,
 	int rc;
 
 	dsec = inode_security(dir);
-	sbsec = dir->i_sb->s_security;
+	sbsec = selinux_superblock(dir->i_sb);
 
 	sid = tsec->sid;
 
@@ -1995,7 +1990,7 @@ static int superblock_has_perm(const struct cred *cred,
 	struct superblock_security_struct *sbsec;
 	u32 sid = cred_sid(cred);
 
-	sbsec = sb->s_security;
+	sbsec = selinux_superblock(sb);
 	return avc_has_perm(&selinux_state,
 			    sid, sbsec->sid, SECCLASS_FILESYSTEM, perms, ad);
 }
@@ -2617,11 +2612,7 @@ static void selinux_bprm_committed_creds(struct linux_binprm *bprm)
 
 static int selinux_sb_alloc_security(struct super_block *sb)
 {
-	struct superblock_security_struct *sbsec;
-
-	sbsec = kzalloc(sizeof(struct superblock_security_struct), GFP_KERNEL);
-	if (!sbsec)
-		return -ENOMEM;
+	struct superblock_security_struct *sbsec = selinux_superblock(sb);
 
 	mutex_init(&sbsec->lock);
 	INIT_LIST_HEAD(&sbsec->isec_head);
@@ -2629,16 +2620,10 @@ static int selinux_sb_alloc_security(struct super_block *sb)
 	sbsec->sid = SECINITSID_UNLABELED;
 	sbsec->def_sid = SECINITSID_FILE;
 	sbsec->mntpoint_sid = SECINITSID_UNLABELED;
-	sb->s_security = sbsec;
 
 	return 0;
 }
 
-static void selinux_sb_free_security(struct super_block *sb)
-{
-	superblock_free_security(sb);
-}
-
 static inline int opt_len(const char *s)
 {
 	bool open_quote = false;
@@ -2772,7 +2757,7 @@ static int selinux_sb_mnt_opts_compat(struct super_block *sb, void *mnt_opts)
 static int selinux_sb_remount(struct super_block *sb, void *mnt_opts)
 {
 	struct selinux_mnt_opts *opts = mnt_opts;
-	struct superblock_security_struct *sbsec = sb->s_security;
+	struct superblock_security_struct *sbsec = selinux_superblock(sb);
 	u32 sid;
 	int rc;
 
@@ -3010,7 +2995,7 @@ static int selinux_inode_init_security(struct inode *inode, struct inode *dir,
 	int rc;
 	char *context;
 
-	sbsec = dir->i_sb->s_security;
+	sbsec = selinux_superblock(dir->i_sb);
 
 	newsid = tsec->create_sid;
 
@@ -3312,7 +3297,7 @@ static int selinux_inode_setxattr(struct user_namespace *mnt_userns,
 	if (!selinux_initialized(&selinux_state))
 		return (inode_owner_or_capable(mnt_userns, inode) ? 0 : -EPERM);
 
-	sbsec = inode->i_sb->s_security;
+	sbsec = selinux_superblock(inode->i_sb);
 	if (!(sbsec->flags & SBLABEL_MNT))
 		return -EOPNOTSUPP;
 
@@ -3557,13 +3542,14 @@ static int selinux_inode_setsecurity(struct inode *inode, const char *name,
 				     const void *value, size_t size, int flags)
 {
 	struct inode_security_struct *isec = inode_security_novalidate(inode);
-	struct superblock_security_struct *sbsec = inode->i_sb->s_security;
+	struct superblock_security_struct *sbsec;
 	u32 newsid;
 	int rc;
 
 	if (strcmp(name, XATTR_SELINUX_SUFFIX))
 		return -EOPNOTSUPP;
 
+	sbsec = selinux_superblock(inode->i_sb);
 	if (!(sbsec->flags & SBLABEL_MNT))
 		return -EOPNOTSUPP;
 
@@ -7065,6 +7051,7 @@ struct lsm_blob_sizes selinux_blob_sizes __lsm_ro_after_init = {
 	.lbs_inode = sizeof(struct inode_security_struct),
 	.lbs_ipc = sizeof(struct ipc_security_struct),
 	.lbs_msg_msg = sizeof(struct msg_security_struct),
+	.lbs_superblock = sizeof(struct superblock_security_struct),
 };
 
 #ifdef CONFIG_PERF_EVENTS
@@ -7165,7 +7152,6 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(bprm_committing_creds, selinux_bprm_committing_creds),
 	LSM_HOOK_INIT(bprm_committed_creds, selinux_bprm_committed_creds),
 
-	LSM_HOOK_INIT(sb_free_security, selinux_sb_free_security),
 	LSM_HOOK_INIT(sb_free_mnt_opts, selinux_free_mnt_opts),
 	LSM_HOOK_INIT(sb_mnt_opts_compat, selinux_sb_mnt_opts_compat),
 	LSM_HOOK_INIT(sb_remount, selinux_sb_remount),