UBUNTU: SAUCE: apparmor4.0.0 [35/90]: LSM stacking v39: LSM: allocate mnt_opts blobs instead of module specific data

BugLink: http://bugs.launchpad.net/bugs/2028253

Replace allocations of LSM specific mount data with the
shared mnt_opts blob.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
(cherry picked from commit 82587147aafee1cd0d3ef871cb9bf842235c281d
https://git.launchpad.net/~apparmor-dev/ubuntu-kernel-next)
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>

include/linux/lsm_hooks.h

@@ -156,5 +156,6 @@ extern struct lsm_info __start_early_lsm_info[], __end_early_lsm_info[];
 		__aligned(sizeof(unsigned long))
 
 extern int lsm_inode_alloc(struct inode *inode);
+extern void *lsm_mnt_opts_alloc(gfp_t priority);
 
 #endif /* ! __LINUX_LSM_HOOKS_H */

security/security.c

@@ -1390,6 +1390,18 @@ void security_sb_free(struct super_block *sb)
 	sb->s_security = NULL;
 }
 
+/**
+ * lsm_mnt_opts_alloc - allocate a mnt_opts blob
+ * @priority: memory allocation priority
+ *
+ * Returns a newly allocated mnt_opts blob or NULL if
+ * memory isn't available.
+ */
+void *lsm_mnt_opts_alloc(gfp_t priority)
+{
+	return kzalloc(blob_sizes.lbs_mnt_opts, priority);
+}
+
 /**
  * security_free_mnt_opts() - Free memory associated with mount options
  * @mnt_opts: LSM processed mount options

security/selinux/hooks.c

@@ -2799,7 +2799,7 @@ static int selinux_fs_context_submount(struct fs_context *fc,
 	if (!(sbsec->flags & (FSCONTEXT_MNT|CONTEXT_MNT|DEFCONTEXT_MNT)))
 		return 0;
 
-	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
+	opts = lsm_mnt_opts_alloc(GFP_KERNEL);
 	if (!opts)
 		return -ENOMEM;
 
@@ -2821,8 +2821,12 @@ static int selinux_fs_context_dup(struct fs_context *fc,
 	if (!src)
 		return 0;
 
-	fc->security = kmemdup(src, sizeof(*src), GFP_KERNEL);
-	return fc->security ? 0 : -ENOMEM;
+	fc->security = lsm_mnt_opts_alloc(GFP_KERNEL);
+	if (!fc->security)
+		return -ENOMEM;
+
+	memcpy(fc->security, src, sizeof(*src));
+	return 0;
 }
 
 static const struct fs_parameter_spec selinux_fs_parameters[] = {

security/smack/smack_lsm.c

@@ -639,7 +639,7 @@ static int smack_fs_context_submount(struct fs_context *fc,
 	struct smack_mnt_opts *ctx;
 	struct inode_smack *isp;
 
-	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+	ctx = lsm_mnt_opts_alloc(GFP_KERNEL);
 	if (!ctx)
 		return -ENOMEM;
 	fc->security = ctx;
@@ -690,7 +690,7 @@ static int smack_fs_context_dup(struct fs_context *fc,
 	if (!src)
 		return 0;
 
-	fc->security = kzalloc(sizeof(struct smack_mnt_opts), GFP_KERNEL);
+	fc->security = lsm_mnt_opts_alloc(GFP_KERNEL);
 	if (!fc->security)
 		return -ENOMEM;