selinux: switch to private struct selinux_mnt_opts

none of the convolutions needed, just 4 strings, TYVM...
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

security/selinux/hooks.c

@@ -433,16 +433,17 @@ static void superblock_free_security(struct super_block *sb)
 	kfree(sbsec);
 }
 
+struct selinux_mnt_opts {
+	const char *fscontext, *context, *rootcontext, *defcontext;
+};
+
 static void selinux_free_mnt_opts(void *mnt_opts)
 {
-	struct security_mnt_opts *opts = mnt_opts;
-	int i;
-
-	if (opts->mnt_opts)
-		for (i = 0; i < opts->num_mnt_opts; i++)
-			kfree(opts->mnt_opts[i]);
-	kfree(opts->mnt_opts);
-	kfree(opts->mnt_opts_flags);
+	struct selinux_mnt_opts *opts = mnt_opts;
+	kfree(opts->fscontext);
+	kfree(opts->context);
+	kfree(opts->rootcontext);
+	kfree(opts->defcontext);
 	kfree(opts);
 }
 
@@ -624,6 +625,17 @@ static int bad_option(struct superblock_security_struct *sbsec, char flag,
 	return 0;
 }
 
+static int parse_sid(struct super_block *sb, const char *s, u32 *sid)
+{
+	int rc = security_context_str_to_sid(&selinux_state, s,
+					     sid, GFP_KERNEL);
+	if (rc)
+		pr_warn("SELinux: security_context_str_to_sid"
+		       "(%s) failed for (dev %s, type %s) errno=%d\n",
+		       s, sb->s_id, sb->s_type->name, rc);
+	return rc;
+}
+
 /*
  * Allow filesystems with binary mount data to explicitly set mount point
  * labeling information.
@@ -634,22 +646,18 @@ static int selinux_set_mnt_opts(struct super_block *sb,
 				unsigned long *set_kern_flags)
 {
 	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 dentry *root = sbsec->sb->s_root;
+	struct selinux_mnt_opts *opts = mnt_opts;
 	struct inode_security_struct *root_isec;
 	u32 fscontext_sid = 0, context_sid = 0, rootcontext_sid = 0;
 	u32 defcontext_sid = 0;
-	struct security_mnt_opts *opts = mnt_opts;
-	char **mount_options = opts ? opts->mnt_opts : NULL;
-	int *flags = opts ? opts->mnt_opts_flags : NULL;
-	int num_opts = opts ? opts->num_mnt_opts : 0;
+	int rc = 0;
 
 	mutex_lock(&sbsec->lock);
 
 	if (!selinux_state.initialized) {
-		if (!num_opts) {
+		if (!opts) {
 			/* Defer initialization until selinux_complete_init,
 			   after the initial policy is loaded and the security
 			   server is ready to handle calls. */
@@ -679,7 +687,7 @@ static int selinux_set_mnt_opts(struct super_block *sb,
 	 * will be used for both mounts)
 	 */
 	if ((sbsec->flags & SE_SBINITIALIZED) && (sb->s_type->fs_flags & FS_BINARY_MOUNTDATA)
-	    && (num_opts == 0))
+	    && !opts)
 		goto out;
 
 	root_isec = backing_inode_security_novalidate(root);
@@ -689,68 +697,48 @@ static int selinux_set_mnt_opts(struct super_block *sb,
 	 * also check if someone is trying to mount the same sb more
 	 * than once with different security options.
 	 */
-	for (i = 0; i < num_opts; i++) {
-		u32 sid;
-
-		if (flags[i] == SBLABEL_MNT)
-			continue;
-		rc = security_context_str_to_sid(&selinux_state,
-						 mount_options[i], &sid,
-						 GFP_KERNEL);
-		if (rc) {
-			pr_warn("SELinux: security_context_str_to_sid"
-			       "(%s) failed for (dev %s, type %s) errno=%d\n",
-			       mount_options[i], sb->s_id, name, rc);
-			goto out;
-		}
-		switch (flags[i]) {
-		case FSCONTEXT_MNT:
-			fscontext_sid = sid;
-
+	if (opts) {
+		if (opts->fscontext) {
+			rc = parse_sid(sb, opts->fscontext, &fscontext_sid);
+			if (rc)
+				goto out;
 			if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid,
 					fscontext_sid))
 				goto out_double_mount;
-
 			sbsec->flags |= FSCONTEXT_MNT;
-			break;
-		case CONTEXT_MNT:
-			context_sid = sid;
-
+		}
+		if (opts->context) {
+			rc = parse_sid(sb, opts->context, &context_sid);
+			if (rc)
+				goto out;
 			if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid,
 					context_sid))
 				goto out_double_mount;
-
 			sbsec->flags |= CONTEXT_MNT;
-			break;
-		case ROOTCONTEXT_MNT:
-			rootcontext_sid = sid;
-
+		}
+		if (opts->rootcontext) {
+			rc = parse_sid(sb, opts->rootcontext, &rootcontext_sid);
+			if (rc)
+				goto out;
 			if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid,
 					rootcontext_sid))
 				goto out_double_mount;
-
 			sbsec->flags |= ROOTCONTEXT_MNT;
-
-			break;
-		case DEFCONTEXT_MNT:
-			defcontext_sid = sid;
-
+		}
+		if (opts->defcontext) {
+			rc = parse_sid(sb, opts->defcontext, &defcontext_sid);
+			if (rc)
+				goto out;
 			if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid,
 					defcontext_sid))
 				goto out_double_mount;
-
 			sbsec->flags |= DEFCONTEXT_MNT;
-
-			break;
-		default:
-			rc = -EINVAL;
-			goto out;
 		}
 	}
 
 	if (sbsec->flags & SE_SBINITIALIZED) {
 		/* previously mounted with options, but not on this attempt? */
-		if ((sbsec->flags & SE_MNTMASK) && !num_opts)
+		if ((sbsec->flags & SE_MNTMASK) && !opts)
 			goto out_double_mount;
 		rc = 0;
 		goto out;
@@ -883,7 +871,8 @@ static int selinux_set_mnt_opts(struct super_block *sb,
 out_double_mount:
 	rc = -EINVAL;
 	pr_warn("SELinux: mount invalid.  Same superblock, different "
-	       "security settings for (dev %s, type %s)\n", sb->s_id, name);
+	       "security settings for (dev %s, type %s)\n", sb->s_id,
+	       sb->s_type->name);
 	goto out;
 }
 
@@ -998,20 +987,9 @@ static int selinux_sb_clone_mnt_opts(const struct super_block *oldsb,
 static int selinux_parse_opts_str(char *options,
 				  void **mnt_opts)
 {
+	struct selinux_mnt_opts *opts = *mnt_opts;
 	char *p;
-	char *context = NULL, *defcontext = NULL;
-	char *fscontext = NULL, *rootcontext = NULL;
-	int rc, num_mnt_opts = 0;
-	struct security_mnt_opts *opts = *mnt_opts;
-
-	if (!opts) {
-		opts = kzalloc(sizeof(struct security_mnt_opts), GFP_KERNEL);
-		*mnt_opts = opts;
-		if (!opts)
-			return -ENOMEM;
-	}
-
-	opts->num_mnt_opts = 0;
+	int rc;
 
 	/* Standard string-based options. */
 	while ((p = strsep(&options, "|")) != NULL) {
@@ -1023,54 +1001,60 @@ static int selinux_parse_opts_str(char *options,
 
 		token = match_token(p, tokens, args);
 
+		if (!opts) {
+			opts = kzalloc(sizeof(struct selinux_mnt_opts), GFP_KERNEL);
+			if (!opts)
+				return -ENOMEM;
+		}
+
 		switch (token) {
 		case Opt_context:
-			if (context || defcontext) {
+			if (opts->context || opts->defcontext) {
 				rc = -EINVAL;
 				pr_warn(SEL_MOUNT_FAIL_MSG);
 				goto out_err;
 			}
-			context = match_strdup(&args[0]);
-			if (!context) {
+			opts->context = match_strdup(&args[0]);
+			if (!opts->context) {
 				rc = -ENOMEM;
 				goto out_err;
 			}
 			break;
 
 		case Opt_fscontext:
-			if (fscontext) {
+			if (opts->fscontext) {
 				rc = -EINVAL;
 				pr_warn(SEL_MOUNT_FAIL_MSG);
 				goto out_err;
 			}
-			fscontext = match_strdup(&args[0]);
-			if (!fscontext) {
+			opts->fscontext = match_strdup(&args[0]);
+			if (!opts->fscontext) {
 				rc = -ENOMEM;
 				goto out_err;
 			}
 			break;
 
 		case Opt_rootcontext:
-			if (rootcontext) {
+			if (opts->rootcontext) {
 				rc = -EINVAL;
 				pr_warn(SEL_MOUNT_FAIL_MSG);
 				goto out_err;
 			}
-			rootcontext = match_strdup(&args[0]);
-			if (!rootcontext) {
+			opts->rootcontext = match_strdup(&args[0]);
+			if (!opts->rootcontext) {
 				rc = -ENOMEM;
 				goto out_err;
 			}
 			break;
 
 		case Opt_defcontext:
-			if (context || defcontext) {
+			if (opts->context || opts->defcontext) {
 				rc = -EINVAL;
 				pr_warn(SEL_MOUNT_FAIL_MSG);
 				goto out_err;
 			}
-			defcontext = match_strdup(&args[0]);
-			if (!defcontext) {
+			opts->defcontext = match_strdup(&args[0]);
+			if (!opts->defcontext) {
 				rc = -ENOMEM;
 				goto out_err;
 			}
@@ -1084,43 +1068,12 @@ static int selinux_parse_opts_str(char *options,
 
 		}
 	}
-
-	rc = -ENOMEM;
-	opts->mnt_opts = kcalloc(NUM_SEL_MNT_OPTS, sizeof(char *), GFP_KERNEL);
-	if (!opts->mnt_opts)
-		goto out_err;
-
-	opts->mnt_opts_flags = kcalloc(NUM_SEL_MNT_OPTS, sizeof(int),
-				       GFP_KERNEL);
-	if (!opts->mnt_opts_flags)
-		goto out_err;
-
-	if (fscontext) {
-		opts->mnt_opts[num_mnt_opts] = fscontext;
-		opts->mnt_opts_flags[num_mnt_opts++] = FSCONTEXT_MNT;
-	}
-	if (context) {
-		opts->mnt_opts[num_mnt_opts] = context;
-		opts->mnt_opts_flags[num_mnt_opts++] = CONTEXT_MNT;
-	}
-	if (rootcontext) {
-		opts->mnt_opts[num_mnt_opts] = rootcontext;
-		opts->mnt_opts_flags[num_mnt_opts++] = ROOTCONTEXT_MNT;
-	}
-	if (defcontext) {
-		opts->mnt_opts[num_mnt_opts] = defcontext;
-		opts->mnt_opts_flags[num_mnt_opts++] = DEFCONTEXT_MNT;
-	}
-
-	opts->num_mnt_opts = num_mnt_opts;
+	*mnt_opts = opts;
 	return 0;
 
 out_err:
-	security_free_mnt_opts(mnt_opts);
-	kfree(context);
-	kfree(defcontext);
-	kfree(fscontext);
-	kfree(rootcontext);
+	if (opts)
+		selinux_free_mnt_opts(opts);
 	return rc;
 }
 
@@ -2752,10 +2705,10 @@ static int selinux_sb_eat_lsm_opts(char *options, void **mnt_opts)
 
 static int selinux_sb_remount(struct super_block *sb, void *mnt_opts)
 {
-	struct security_mnt_opts *opts = mnt_opts;
-	int i, *flags;
-	char **mount_options;
+	struct selinux_mnt_opts *opts = mnt_opts;
 	struct superblock_security_struct *sbsec = sb->s_security;
+	u32 sid;
+	int rc;
 
 	if (!(sbsec->flags & SE_SBINITIALIZED))
 		return 0;
@@ -2763,48 +2716,35 @@ static int selinux_sb_remount(struct super_block *sb, void *mnt_opts)
 	if (!opts)
 		return 0;
 
-	mount_options = opts->mnt_opts;
-	flags = opts->mnt_opts_flags;
-
-	for (i = 0; i < opts->num_mnt_opts; i++) {
-		u32 sid;
-		int rc;
-
-		if (flags[i] == SBLABEL_MNT)
-			continue;
-		rc = security_context_str_to_sid(&selinux_state,
-						 mount_options[i], &sid,
-						 GFP_KERNEL);
-		if (rc) {
-			pr_warn("SELinux: security_context_str_to_sid"
-			       "(%s) failed for (dev %s, type %s) errno=%d\n",
-			       mount_options[i], sb->s_id, sb->s_type->name, rc);
+	if (opts->fscontext) {
+		rc = parse_sid(sb, opts->fscontext, &sid);
+		if (rc)
 			return rc;
-		}
-		switch (flags[i]) {
-		case FSCONTEXT_MNT:
-			if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid, sid))
-				goto out_bad_option;
-			break;
-		case CONTEXT_MNT:
-			if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid, sid))
-				goto out_bad_option;
-			break;
-		case ROOTCONTEXT_MNT: {
-			struct inode_security_struct *root_isec;
-			root_isec = backing_inode_security(sb->s_root);
-
-			if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid, sid))
-				goto out_bad_option;
-			break;
-		}
-		case DEFCONTEXT_MNT:
-			if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid, sid))
-				goto out_bad_option;
-			break;
-		default:
-			return -EINVAL;
-		}
+		if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid, sid))
+			goto out_bad_option;
+	}
+	if (opts->context) {
+		rc = parse_sid(sb, opts->context, &sid);
+		if (rc)
+			return rc;
+		if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid, sid))
+			goto out_bad_option;
+	}
+	if (opts->rootcontext) {
+		struct inode_security_struct *root_isec;
+		root_isec = backing_inode_security(sb->s_root);
+		rc = parse_sid(sb, opts->rootcontext, &sid);
+		if (rc)
+			return rc;
+		if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid, sid))
+			goto out_bad_option;
+	}
+	if (opts->defcontext) {
+		rc = parse_sid(sb, opts->defcontext, &sid);
+		if (rc)
+			return rc;
+		if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid, sid))
+			goto out_bad_option;
 	}
 	return 0;