TOMOYO: Use RCU primitives for list operation

Replace list operation with RCU primitives and replace
down_read()/up_read() with srcu_read_lock()/srcu_read_unlock().

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 77 insertions, 33 deletions

diff --git a/security/tomoyo/file.c b/security/tomoyo/file.c
index 482f0e7ed99..3c472867634 100644
--- a/security/tomoyo/file.c
+++ b/security/tomoyo/file.c
@@ -213,6 +213,8 @@ static DECLARE_RWSEM(tomoyo_globally_readable_list_lock);
  * @is_delete: True if it is a delete request.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_update_globally_readable_entry(const char *filename,
 						 const bool is_delete)
@@ -228,7 +230,7 @@ static int tomoyo_update_globally_readable_entry(const char *filename,
 	if (!saved_filename)
 		return -ENOMEM;
 	down_write(&tomoyo_globally_readable_list_lock);
-	list_for_each_entry(ptr, &tomoyo_globally_readable_list, list) {
+	list_for_each_entry_rcu(ptr, &tomoyo_globally_readable_list, list) {
 		if (ptr->filename != saved_filename)
 			continue;
 		ptr->is_deleted = is_delete;
@@ -243,7 +245,7 @@ static int tomoyo_update_globally_readable_entry(const char *filename,
 	if (!new_entry)
 		goto out;
 	new_entry->filename = saved_filename;
-	list_add_tail(&new_entry->list, &tomoyo_globally_readable_list);
+	list_add_tail_rcu(&new_entry->list, &tomoyo_globally_readable_list);
 	error = 0;
  out:
 	up_write(&tomoyo_globally_readable_list_lock);
@@ -256,21 +258,22 @@ static int tomoyo_update_globally_readable_entry(const char *filename,
  * @filename: The filename to check.
  *
  * Returns true if any domain can open @filename for reading, false otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static bool tomoyo_is_globally_readable_file(const struct tomoyo_path_info *
 					     filename)
 {
 	struct tomoyo_globally_readable_file_entry *ptr;
 	bool found = false;
-	down_read(&tomoyo_globally_readable_list_lock);
-	list_for_each_entry(ptr, &tomoyo_globally_readable_list, list) {
+
+	list_for_each_entry_rcu(ptr, &tomoyo_globally_readable_list, list) {
 		if (!ptr->is_deleted &&
 		    tomoyo_path_matches_pattern(filename, ptr->filename)) {
 			found = true;
 			break;
 		}
 	}
-	up_read(&tomoyo_globally_readable_list_lock);
 	return found;
 }
 
@@ -281,6 +284,8 @@ static bool tomoyo_is_globally_readable_file(const struct tomoyo_path_info *
  * @is_delete: True if it is a delete request.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 int tomoyo_write_globally_readable_policy(char *data, const bool is_delete)
 {
@@ -293,13 +298,14 @@ int tomoyo_write_globally_readable_policy(char *data, const bool is_delete)
  * @head: Pointer to "struct tomoyo_io_buffer".
  *
  * Returns true on success, false otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 bool tomoyo_read_globally_readable_policy(struct tomoyo_io_buffer *head)
 {
 	struct list_head *pos;
 	bool done = true;
 
-	down_read(&tomoyo_globally_readable_list_lock);
 	list_for_each_cookie(pos, head->read_var2,
 			     &tomoyo_globally_readable_list) {
 		struct tomoyo_globally_readable_file_entry *ptr;
@@ -313,7 +319,6 @@ bool tomoyo_read_globally_readable_policy(struct tomoyo_io_buffer *head)
 		if (!done)
 			break;
 	}
-	up_read(&tomoyo_globally_readable_list_lock);
 	return done;
 }
 
@@ -356,6 +361,8 @@ static DECLARE_RWSEM(tomoyo_pattern_list_lock);
  * @is_delete: True if it is a delete request.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_update_file_pattern_entry(const char *pattern,
 					    const bool is_delete)
@@ -371,7 +378,7 @@ static int tomoyo_update_file_pattern_entry(const char *pattern,
 	if (!saved_pattern)
 		return -ENOMEM;
 	down_write(&tomoyo_pattern_list_lock);
-	list_for_each_entry(ptr, &tomoyo_pattern_list, list) {
+	list_for_each_entry_rcu(ptr, &tomoyo_pattern_list, list) {
 		if (saved_pattern != ptr->pattern)
 			continue;
 		ptr->is_deleted = is_delete;
@@ -386,7 +393,7 @@ static int tomoyo_update_file_pattern_entry(const char *pattern,
 	if (!new_entry)
 		goto out;
 	new_entry->pattern = saved_pattern;
-	list_add_tail(&new_entry->list, &tomoyo_pattern_list);
+	list_add_tail_rcu(&new_entry->list, &tomoyo_pattern_list);
 	error = 0;
  out:
 	up_write(&tomoyo_pattern_list_lock);
@@ -399,6 +406,8 @@ static int tomoyo_update_file_pattern_entry(const char *pattern,
  * @filename: The filename to find patterned pathname.
  *
  * Returns pointer to pathname pattern if matched, @filename otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static const struct tomoyo_path_info *
 tomoyo_get_file_pattern(const struct tomoyo_path_info *filename)
@@ -406,8 +415,7 @@ tomoyo_get_file_pattern(const struct tomoyo_path_info *filename)
 	struct tomoyo_pattern_entry *ptr;
 	const struct tomoyo_path_info *pattern = NULL;
 
-	down_read(&tomoyo_pattern_list_lock);
-	list_for_each_entry(ptr, &tomoyo_pattern_list, list) {
+	list_for_each_entry_rcu(ptr, &tomoyo_pattern_list, list) {
 		if (ptr->is_deleted)
 			continue;
 		if (!tomoyo_path_matches_pattern(filename, ptr->pattern))
@@ -420,7 +428,6 @@ tomoyo_get_file_pattern(const struct tomoyo_path_info *filename)
 			break;
 		}
 	}
-	up_read(&tomoyo_pattern_list_lock);
 	if (pattern)
 		filename = pattern;
 	return filename;
@@ -433,6 +440,8 @@ tomoyo_get_file_pattern(const struct tomoyo_path_info *filename)
  * @is_delete: True if it is a delete request.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 int tomoyo_write_pattern_policy(char *data, const bool is_delete)
 {
@@ -445,13 +454,14 @@ int tomoyo_write_pattern_policy(char *data, const bool is_delete)
  * @head: Pointer to "struct tomoyo_io_buffer".
  *
  * Returns true on success, false otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 bool tomoyo_read_file_pattern(struct tomoyo_io_buffer *head)
 {
 	struct list_head *pos;
 	bool done = true;
 
-	down_read(&tomoyo_pattern_list_lock);
 	list_for_each_cookie(pos, head->read_var2, &tomoyo_pattern_list) {
 		struct tomoyo_pattern_entry *ptr;
 		ptr = list_entry(pos, struct tomoyo_pattern_entry, list);
@@ -462,7 +472,6 @@ bool tomoyo_read_file_pattern(struct tomoyo_io_buffer *head)
 		if (!done)
 			break;
 	}
-	up_read(&tomoyo_pattern_list_lock);
 	return done;
 }
 
@@ -505,6 +514,8 @@ static DECLARE_RWSEM(tomoyo_no_rewrite_list_lock);
  * @is_delete: True if it is a delete request.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_update_no_rewrite_entry(const char *pattern,
 					  const bool is_delete)
@@ -519,7 +530,7 @@ static int tomoyo_update_no_rewrite_entry(const char *pattern,
 	if (!saved_pattern)
 		return -ENOMEM;
 	down_write(&tomoyo_no_rewrite_list_lock);
-	list_for_each_entry(ptr, &tomoyo_no_rewrite_list, list) {
+	list_for_each_entry_rcu(ptr, &tomoyo_no_rewrite_list, list) {
 		if (ptr->pattern != saved_pattern)
 			continue;
 		ptr->is_deleted = is_delete;
@@ -534,7 +545,7 @@ static int tomoyo_update_no_rewrite_entry(const char *pattern,
 	if (!new_entry)
 		goto out;
 	new_entry->pattern = saved_pattern;
-	list_add_tail(&new_entry->list, &tomoyo_no_rewrite_list);
+	list_add_tail_rcu(&new_entry->list, &tomoyo_no_rewrite_list);
 	error = 0;
  out:
 	up_write(&tomoyo_no_rewrite_list_lock);
@@ -548,14 +559,15 @@ static int tomoyo_update_no_rewrite_entry(const char *pattern,
  *
  * Returns true if @filename is specified by "deny_rewrite" directive,
  * false otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static bool tomoyo_is_no_rewrite_file(const struct tomoyo_path_info *filename)
 {
 	struct tomoyo_no_rewrite_entry *ptr;
 	bool found = false;
 
-	down_read(&tomoyo_no_rewrite_list_lock);
-	list_for_each_entry(ptr, &tomoyo_no_rewrite_list, list) {
+	list_for_each_entry_rcu(ptr, &tomoyo_no_rewrite_list, list) {
 		if (ptr->is_deleted)
 			continue;
 		if (!tomoyo_path_matches_pattern(filename, ptr->pattern))
@@ -563,7 +575,6 @@ static bool tomoyo_is_no_rewrite_file(const struct tomoyo_path_info *filename)
 		found = true;
 		break;
 	}
-	up_read(&tomoyo_no_rewrite_list_lock);
 	return found;
 }
 
@@ -574,6 +585,8 @@ static bool tomoyo_is_no_rewrite_file(const struct tomoyo_path_info *filename)
  * @is_delete: True if it is a delete request.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 int tomoyo_write_no_rewrite_policy(char *data, const bool is_delete)
 {
@@ -586,13 +599,14 @@ int tomoyo_write_no_rewrite_policy(char *data, const bool is_delete)
  * @head: Pointer to "struct tomoyo_io_buffer".
  *
  * Returns true on success, false otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 bool tomoyo_read_no_rewrite_policy(struct tomoyo_io_buffer *head)
 {
 	struct list_head *pos;
 	bool done = true;
 
-	down_read(&tomoyo_no_rewrite_list_lock);
 	list_for_each_cookie(pos, head->read_var2, &tomoyo_no_rewrite_list) {
 		struct tomoyo_no_rewrite_entry *ptr;
 		ptr = list_entry(pos, struct tomoyo_no_rewrite_entry, list);
@@ -603,7 +617,6 @@ bool tomoyo_read_no_rewrite_policy(struct tomoyo_io_buffer *head)
 		if (!done)
 			break;
 	}
-	up_read(&tomoyo_no_rewrite_list_lock);
 	return done;
 }
 
@@ -621,6 +634,8 @@ bool tomoyo_read_no_rewrite_policy(struct tomoyo_io_buffer *head)
  * Current policy syntax uses "allow_read/write" instead of "6",
  * "allow_read" instead of "4", "allow_write" instead of "2",
  * "allow_execute" instead of "1".
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_update_file_acl(const char *filename, u8 perm,
 				  struct tomoyo_domain_info * const domain,
@@ -658,6 +673,8 @@ static int tomoyo_update_file_acl(const char *filename, u8 perm,
  * @may_use_pattern: True if patterned ACL is permitted.
  *
  * Returns 0 on success, -EPERM otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_check_single_path_acl2(const struct tomoyo_domain_info *
 					 domain,
@@ -669,8 +686,7 @@ static int tomoyo_check_single_path_acl2(const struct tomoyo_domain_info *
 	struct tomoyo_acl_info *ptr;
 	int error = -EPERM;
 
-	down_read(&tomoyo_domain_acl_info_list_lock);
-	list_for_each_entry(ptr, &domain->acl_info_list, list) {
+	list_for_each_entry_rcu(ptr, &domain->acl_info_list, list) {
 		struct tomoyo_single_path_acl_record *acl;
 		if (tomoyo_acl_type2(ptr) != TOMOYO_TYPE_SINGLE_PATH_ACL)
 			continue;
@@ -693,7 +709,6 @@ static int tomoyo_check_single_path_acl2(const struct tomoyo_domain_info *
 		error = 0;
 		break;
 	}
-	up_read(&tomoyo_domain_acl_info_list_lock);
 	return error;
 }
 
@@ -705,6 +720,8 @@ static int tomoyo_check_single_path_acl2(const struct tomoyo_domain_info *
  * @operation: Mode ("read" or "write" or "read/write" or "execute").
  *
  * Returns 0 on success, -EPERM otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_check_file_acl(const struct tomoyo_domain_info *domain,
 				 const struct tomoyo_path_info *filename,
@@ -738,6 +755,8 @@ static int tomoyo_check_file_acl(const struct tomoyo_domain_info *domain,
  * @mode:      Access control mode.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_check_file_perm2(struct tomoyo_domain_info * const domain,
 				   const struct tomoyo_path_info *filename,
@@ -791,6 +810,8 @@ static int tomoyo_check_file_perm2(struct tomoyo_domain_info * const domain,
  * @is_delete: True if it is a delete request.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 int tomoyo_write_file_policy(char *data, struct tomoyo_domain_info *domain,
 			     const bool is_delete)
@@ -838,6 +859,8 @@ int tomoyo_write_file_policy(char *data, struct tomoyo_domain_info *domain,
  * @is_delete: True if it is a delete request.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_update_single_path_acl(const u8 type, const char *filename,
 					 struct tomoyo_domain_info *
@@ -861,7 +884,7 @@ static int tomoyo_update_single_path_acl(const u8 type, const char *filename,
 	down_write(&tomoyo_domain_acl_info_list_lock);
 	if (is_delete)
 		goto delete;
-	list_for_each_entry(ptr, &domain->acl_info_list, list) {
+	list_for_each_entry_rcu(ptr, &domain->acl_info_list, list) {
 		if (tomoyo_acl_type1(ptr) != TOMOYO_TYPE_SINGLE_PATH_ACL)
 			continue;
 		acl = container_of(ptr, struct tomoyo_single_path_acl_record,
@@ -894,12 +917,12 @@ static int tomoyo_update_single_path_acl(const u8 type, const char *filename,
 	if (perm == (1 << TOMOYO_TYPE_READ_WRITE_ACL))
 		acl->perm |= rw_mask;
 	acl->filename = saved_filename;
-	list_add_tail(&acl->head.list, &domain->acl_info_list);
+	list_add_tail_rcu(&acl->head.list, &domain->acl_info_list);
 	error = 0;
 	goto out;
  delete:
 	error = -ENOENT;
-	list_for_each_entry(ptr, &domain->acl_info_list, list) {
+	list_for_each_entry_rcu(ptr, &domain->acl_info_list, list) {
 		if (tomoyo_acl_type2(ptr) != TOMOYO_TYPE_SINGLE_PATH_ACL)
 			continue;
 		acl = container_of(ptr, struct tomoyo_single_path_acl_record,
@@ -934,6 +957,8 @@ static int tomoyo_update_single_path_acl(const u8 type, const char *filename,
  * @is_delete: True if it is a delete request.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_update_double_path_acl(const u8 type, const char *filename1,
 					 const char *filename2,
@@ -959,7 +984,7 @@ static int tomoyo_update_double_path_acl(const u8 type, const char *filename1,
 	down_write(&tomoyo_domain_acl_info_list_lock);
 	if (is_delete)
 		goto delete;
-	list_for_each_entry(ptr, &domain->acl_info_list, list) {
+	list_for_each_entry_rcu(ptr, &domain->acl_info_list, list) {
 		if (tomoyo_acl_type1(ptr) != TOMOYO_TYPE_DOUBLE_PATH_ACL)
 			continue;
 		acl = container_of(ptr, struct tomoyo_double_path_acl_record,
@@ -982,12 +1007,12 @@ static int tomoyo_update_double_path_acl(const u8 type, const char *filename1,
 	acl->perm = perm;
 	acl->filename1 = saved_filename1;
 	acl->filename2 = saved_filename2;
-	list_add_tail(&acl->head.list, &domain->acl_info_list);
+	list_add_tail_rcu(&acl->head.list, &domain->acl_info_list);
 	error = 0;
 	goto out;
  delete:
 	error = -ENOENT;
-	list_for_each_entry(ptr, &domain->acl_info_list, list) {
+	list_for_each_entry_rcu(ptr, &domain->acl_info_list, list) {
 		if (tomoyo_acl_type2(ptr) != TOMOYO_TYPE_DOUBLE_PATH_ACL)
 			continue;
 		acl = container_of(ptr, struct tomoyo_double_path_acl_record,
@@ -1014,6 +1039,8 @@ static int tomoyo_update_double_path_acl(const u8 type, const char *filename1,
  * @filename: Filename to check.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_check_single_path_acl(struct tomoyo_domain_info *domain,
 					const u8 type,
@@ -1033,6 +1060,8 @@ static int tomoyo_check_single_path_acl(struct tomoyo_domain_info *domain,
  * @filename2: Second filename to check.
  *
  * Returns 0 on success, -EPERM otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_check_double_path_acl(const struct tomoyo_domain_info *domain,
 					const u8 type,
@@ -1047,8 +1076,7 @@ static int tomoyo_check_double_path_acl(const struct tomoyo_domain_info *domain,
 
 	if (!tomoyo_check_flags(domain, TOMOYO_MAC_FOR_FILE))
 		return 0;
-	down_read(&tomoyo_domain_acl_info_list_lock);
-	list_for_each_entry(ptr, &domain->acl_info_list, list) {
+	list_for_each_entry_rcu(ptr, &domain->acl_info_list, list) {
 		struct tomoyo_double_path_acl_record *acl;
 		if (tomoyo_acl_type2(ptr) != TOMOYO_TYPE_DOUBLE_PATH_ACL)
 			continue;
@@ -1063,7 +1091,6 @@ static int tomoyo_check_double_path_acl(const struct tomoyo_domain_info *domain,
 		error = 0;
 		break;
 	}
-	up_read(&tomoyo_domain_acl_info_list_lock);
 	return error;
 }
 
@@ -1076,6 +1103,8 @@ static int tomoyo_check_double_path_acl(const struct tomoyo_domain_info *domain,
  * @mode:      Access control mode.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_check_single_path_permission2(struct tomoyo_domain_info *
 						const domain, u8 operation,
@@ -1124,6 +1153,8 @@ static int tomoyo_check_single_path_permission2(struct tomoyo_domain_info *
  * @filename: Check permission for "execute".
  *
  * Returns 0 on success, negativevalue otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 int tomoyo_check_exec_perm(struct tomoyo_domain_info *domain,
 			   const struct tomoyo_path_info *filename)
@@ -1152,6 +1183,7 @@ int tomoyo_check_open_permission(struct tomoyo_domain_info *domain,
 	struct tomoyo_path_info *buf;
 	const u8 mode = tomoyo_check_flags(domain, TOMOYO_MAC_FOR_FILE);
 	const bool is_enforce = (mode == 3);
+	int idx;
 
 	if (!mode || !path->mnt)
 		return 0;
@@ -1163,6 +1195,7 @@ int tomoyo_check_open_permission(struct tomoyo_domain_info *domain,
 		 * don't call me.
 		 */
 		return 0;
+	idx = tomoyo_read_lock();
 	buf = tomoyo_get_path(path);
 	if (!buf)
 		goto out;
@@ -1188,6 +1221,7 @@ int tomoyo_check_open_permission(struct tomoyo_domain_info *domain,
 							     buf, mode);
  out:
 	tomoyo_free(buf);
+	tomoyo_read_unlock(idx);
 	if (!is_enforce)
 		error = 0;
 	return error;
@@ -1209,9 +1243,11 @@ int tomoyo_check_1path_perm(struct tomoyo_domain_info *domain,
 	struct tomoyo_path_info *buf;
 	const u8 mode = tomoyo_check_flags(domain, TOMOYO_MAC_FOR_FILE);
 	const bool is_enforce = (mode == 3);
+	int idx;
 
 	if (!mode || !path->mnt)
 		return 0;
+	idx = tomoyo_read_lock();
 	buf = tomoyo_get_path(path);
 	if (!buf)
 		goto out;
@@ -1231,6 +1267,7 @@ int tomoyo_check_1path_perm(struct tomoyo_domain_info *domain,
 						     mode);
  out:
 	tomoyo_free(buf);
+	tomoyo_read_unlock(idx);
 	if (!is_enforce)
 		error = 0;
 	return error;
@@ -1251,9 +1288,12 @@ int tomoyo_check_rewrite_permission(struct tomoyo_domain_info *domain,
 	const u8 mode = tomoyo_check_flags(domain, TOMOYO_MAC_FOR_FILE);
 	const bool is_enforce = (mode == 3);
 	struct tomoyo_path_info *buf;
+	int idx;
 
 	if (!mode || !filp->f_path.mnt)
 		return 0;
+
+	idx = tomoyo_read_lock();
 	buf = tomoyo_get_path(&filp->f_path);
 	if (!buf)
 		goto out;
@@ -1266,6 +1306,7 @@ int tomoyo_check_rewrite_permission(struct tomoyo_domain_info *domain,
 						     buf, mode);
  out:
 	tomoyo_free(buf);
+	tomoyo_read_unlock(idx);
 	if (!is_enforce)
 		error = 0;
 	return error;
@@ -1290,9 +1331,11 @@ int tomoyo_check_2path_perm(struct tomoyo_domain_info * const domain,
 	const u8 mode = tomoyo_check_flags(domain, TOMOYO_MAC_FOR_FILE);
 	const bool is_enforce = (mode == 3);
 	const char *msg;
+	int idx;
 
 	if (!mode || !path1->mnt || !path2->mnt)
 		return 0;
+	idx = tomoyo_read_lock();
 	buf1 = tomoyo_get_path(path1);
 	buf2 = tomoyo_get_path(path2);
 	if (!buf1 || !buf2)
@@ -1331,6 +1374,7 @@ int tomoyo_check_2path_perm(struct tomoyo_domain_info * const domain,
  out:
 	tomoyo_free(buf1);
 	tomoyo_free(buf2);
+	tomoyo_read_unlock(idx);
 	if (!is_enforce)
 		error = 0;
 	return error;