TOMOYO: Use stack memory for pending entry.

Use stack memory for pending entry to reduce kmalloc() which will be kfree()d.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 83 insertions, 98 deletions

diff --git a/security/tomoyo/file.c b/security/tomoyo/file.c
index 060bbf3870ce..6651cac87625 100644
--- a/security/tomoyo/file.c
+++ b/security/tomoyo/file.c
@@ -164,38 +164,36 @@ LIST_HEAD(tomoyo_globally_readable_list);
 static int tomoyo_update_globally_readable_entry(const char *filename,
                                                  const bool is_delete)
 {
-        struct tomoyo_globally_readable_file_entry *entry = NULL;
         struct tomoyo_globally_readable_file_entry *ptr;
-        const struct tomoyo_path_info *saved_filename;
+        struct tomoyo_globally_readable_file_entry e = { };
         int error = is_delete ? -ENOENT : -ENOMEM;
 
         if (!tomoyo_is_correct_path(filename, 1, 0, -1))
                 return -EINVAL;
-        saved_filename = tomoyo_get_name(filename);
-        if (!saved_filename)
+        e.filename = tomoyo_get_name(filename);
+        if (!e.filename)
                 return -ENOMEM;
-        if (!is_delete)
-                entry = kmalloc(sizeof(*entry), GFP_NOFS);
         if (mutex_lock_interruptible(&tomoyo_policy_lock))
                 goto out;
         list_for_each_entry_rcu(ptr, &tomoyo_globally_readable_list, list) {
-                if (ptr->filename != saved_filename)
+                if (ptr->filename != e.filename)
                         continue;
                 ptr->is_deleted = is_delete;
                 error = 0;
                 break;
         }
-        if (!is_delete && error && tomoyo_memory_ok(entry)) {
-                entry->filename = saved_filename;
-                saved_filename = NULL;
-                list_add_tail_rcu(&entry->list, &tomoyo_globally_readable_list);
-                entry = NULL;
-                error = 0;
+        if (!is_delete && error) {
+                struct tomoyo_globally_readable_file_entry *entry =
+                        tomoyo_commit_ok(&e, sizeof(e));
+                if (entry) {
+                        list_add_tail_rcu(&entry->list,
+                                          &tomoyo_globally_readable_list);
+                        error = 0;
+                }
         }
         mutex_unlock(&tomoyo_policy_lock);
  out:
-        tomoyo_put_name(saved_filename);
-        kfree(entry);
+        tomoyo_put_name(e.filename);
         return error;
 }
 
@@ -313,38 +311,34 @@ LIST_HEAD(tomoyo_pattern_list);
 static int tomoyo_update_file_pattern_entry(const char *pattern,
                                             const bool is_delete)
 {
-        struct tomoyo_pattern_entry *entry = NULL;
         struct tomoyo_pattern_entry *ptr;
-        const struct tomoyo_path_info *saved_pattern;
+        struct tomoyo_pattern_entry e = { .pattern = tomoyo_get_name(pattern) };
         int error = is_delete ? -ENOENT : -ENOMEM;
 
-        saved_pattern = tomoyo_get_name(pattern);
-        if (!saved_pattern)
+        if (!e.pattern)
                 return error;
-        if (!saved_pattern->is_patterned)
+        if (!e.pattern->is_patterned)
                 goto out;
-        if (!is_delete)
-                entry = kmalloc(sizeof(*entry), GFP_NOFS);
         if (mutex_lock_interruptible(&tomoyo_policy_lock))
                 goto out;
         list_for_each_entry_rcu(ptr, &tomoyo_pattern_list, list) {
-                if (saved_pattern != ptr->pattern)
+                if (e.pattern != ptr->pattern)
                         continue;
                 ptr->is_deleted = is_delete;
                 error = 0;
                 break;
         }
-        if (!is_delete && error && tomoyo_memory_ok(entry)) {
-                entry->pattern = saved_pattern;
-                saved_pattern = NULL;
-                list_add_tail_rcu(&entry->list, &tomoyo_pattern_list);
-                entry = NULL;
-                error = 0;
+        if (!is_delete && error) {
+                struct tomoyo_pattern_entry *entry =
+                        tomoyo_commit_ok(&e, sizeof(e));
+                if (entry) {
+                        list_add_tail_rcu(&entry->list, &tomoyo_pattern_list);
+                        error = 0;
+                }
         }
         mutex_unlock(&tomoyo_policy_lock);
  out:
-        kfree(entry);
-        tomoyo_put_name(saved_pattern);
+        tomoyo_put_name(e.pattern);
         return error;
 }
 
@@ -467,38 +461,36 @@ LIST_HEAD(tomoyo_no_rewrite_list);
 static int tomoyo_update_no_rewrite_entry(const char *pattern,
                                           const bool is_delete)
 {
-        struct tomoyo_no_rewrite_entry *entry = NULL;
         struct tomoyo_no_rewrite_entry *ptr;
-        const struct tomoyo_path_info *saved_pattern;
+        struct tomoyo_no_rewrite_entry e = { };
         int error = is_delete ? -ENOENT : -ENOMEM;
 
         if (!tomoyo_is_correct_path(pattern, 0, 0, 0))
                 return -EINVAL;
-        saved_pattern = tomoyo_get_name(pattern);
-        if (!saved_pattern)
+        e.pattern = tomoyo_get_name(pattern);
+        if (!e.pattern)
                 return error;
-        if (!is_delete)
-                entry = kmalloc(sizeof(*entry), GFP_NOFS);
         if (mutex_lock_interruptible(&tomoyo_policy_lock))
                 goto out;
         list_for_each_entry_rcu(ptr, &tomoyo_no_rewrite_list, list) {
-                if (ptr->pattern != saved_pattern)
+                if (ptr->pattern != e.pattern)
                         continue;
                 ptr->is_deleted = is_delete;
                 error = 0;
                 break;
         }
-        if (!is_delete && error && tomoyo_memory_ok(entry)) {
-                entry->pattern = saved_pattern;
-                saved_pattern = NULL;
-                list_add_tail_rcu(&entry->list, &tomoyo_no_rewrite_list);
-                entry = NULL;
-                error = 0;
+        if (!is_delete && error) {
+                struct tomoyo_no_rewrite_entry *entry =
+                        tomoyo_commit_ok(&e, sizeof(e));
+                if (entry) {
+                        list_add_tail_rcu(&entry->list,
+                                          &tomoyo_no_rewrite_list);
+                        error = 0;
+                }
         }
         mutex_unlock(&tomoyo_policy_lock);
  out:
-        tomoyo_put_name(saved_pattern);
-        kfree(entry);
+        tomoyo_put_name(e.pattern);
         return error;
 }
 
@@ -810,23 +802,26 @@ static int tomoyo_update_path_acl(const u8 type, const char *filename,
                                   struct tomoyo_domain_info *const domain,
                                   const bool is_delete)
 {
-        static const u32 rw_mask =
+        static const u32 tomoyo_rw_mask =
                 (1 << TOMOYO_TYPE_READ) | (1 << TOMOYO_TYPE_WRITE);
-        const struct tomoyo_path_info *saved_filename;
+        const u32 perm = 1 << type;
         struct tomoyo_acl_info *ptr;
-        struct tomoyo_path_acl *entry = NULL;
+        struct tomoyo_path_acl e = {
+                .head.type = TOMOYO_TYPE_PATH_ACL,
+                .perm_high = perm >> 16,
+                .perm = perm
+        };
         int error = is_delete ? -ENOENT : -ENOMEM;
-        const u32 perm = 1 << type;
 
+        if (type == TOMOYO_TYPE_READ_WRITE)
+                e.perm |= tomoyo_rw_mask;
         if (!domain)
                 return -EINVAL;
         if (!tomoyo_is_correct_path(filename, 0, 0, 0))
                 return -EINVAL;
-        saved_filename = tomoyo_get_name(filename);
-        if (!saved_filename)
+        e.filename = tomoyo_get_name(filename);
+        if (!e.filename)
                 return -ENOMEM;
-        if (!is_delete)
-                entry = kmalloc(sizeof(*entry), GFP_NOFS);
         if (mutex_lock_interruptible(&tomoyo_policy_lock))
                 goto out;
         list_for_each_entry_rcu(ptr, &domain->acl_info_list, list) {
@@ -834,48 +829,42 @@ static int tomoyo_update_path_acl(const u8 type, const char *filename,
                         container_of(ptr, struct tomoyo_path_acl, head);
                 if (ptr->type != TOMOYO_TYPE_PATH_ACL)
                         continue;
-                if (acl->filename != saved_filename)
+                if (acl->filename != e.filename)
                         continue;
                 if (is_delete) {
                         if (perm <= 0xFFFF)
                                 acl->perm &= ~perm;
                         else
                                 acl->perm_high &= ~(perm >> 16);
-                        if ((acl->perm & rw_mask) != rw_mask)
+                        if ((acl->perm & tomoyo_rw_mask) != tomoyo_rw_mask)
                                 acl->perm &= ~(1 << TOMOYO_TYPE_READ_WRITE);
                         else if (!(acl->perm & (1 << TOMOYO_TYPE_READ_WRITE)))
-                                acl->perm &= ~rw_mask;
+                                acl->perm &= ~tomoyo_rw_mask;
                 } else {
                         if (perm <= 0xFFFF)
                                 acl->perm |= perm;
                         else
                                 acl->perm_high |= (perm >> 16);
-                        if ((acl->perm & rw_mask) == rw_mask)
+                        if ((acl->perm & tomoyo_rw_mask) == tomoyo_rw_mask)
                                 acl->perm |= 1 << TOMOYO_TYPE_READ_WRITE;
                         else if (acl->perm & (1 << TOMOYO_TYPE_READ_WRITE))
-                                acl->perm |= rw_mask;
+                                acl->perm |= tomoyo_rw_mask;
                 }
                 error = 0;
                 break;
         }
-        if (!is_delete && error && tomoyo_memory_ok(entry)) {
-                entry->head.type = TOMOYO_TYPE_PATH_ACL;
-                if (perm <= 0xFFFF)
-                        entry->perm = perm;
-                else
-                        entry->perm_high = (perm >> 16);
-                if (perm == (1 << TOMOYO_TYPE_READ_WRITE))
-                        entry->perm |= rw_mask;
-                entry->filename = saved_filename;
-                saved_filename = NULL;
-                list_add_tail_rcu(&entry->head.list, &domain->acl_info_list);
-                entry = NULL;
-                error = 0;
+        if (!is_delete && error) {
+                struct tomoyo_path_acl *entry =
+                        tomoyo_commit_ok(&e, sizeof(e));
+                if (entry) {
+                        list_add_tail_rcu(&entry->head.list,
+                                          &domain->acl_info_list);
+                        error = 0;
+                }
         }
         mutex_unlock(&tomoyo_policy_lock);
  out:
-        kfree(entry);
-        tomoyo_put_name(saved_filename);
+        tomoyo_put_name(e.filename);
         return error;
 }
 
@@ -897,24 +886,23 @@ static int tomoyo_update_path2_acl(const u8 type, const char *filename1,
                                    struct tomoyo_domain_info *const domain,
                                    const bool is_delete)
 {
-        const struct tomoyo_path_info *saved_filename1;
-        const struct tomoyo_path_info *saved_filename2;
+        const u8 perm = 1 << type;
+        struct tomoyo_path2_acl e = {
+                .head.type = TOMOYO_TYPE_PATH2_ACL,
+                .perm = perm
+        };
         struct tomoyo_acl_info *ptr;
-        struct tomoyo_path2_acl *entry = NULL;
         int error = is_delete ? -ENOENT : -ENOMEM;
-        const u8 perm = 1 << type;
 
         if (!domain)
                 return -EINVAL;
         if (!tomoyo_is_correct_path(filename1, 0, 0, 0) ||
             !tomoyo_is_correct_path(filename2, 0, 0, 0))
                 return -EINVAL;
-        saved_filename1 = tomoyo_get_name(filename1);
-        saved_filename2 = tomoyo_get_name(filename2);
-        if (!saved_filename1 || !saved_filename2)
+        e.filename1 = tomoyo_get_name(filename1);
+        e.filename2 = tomoyo_get_name(filename2);
+        if (!e.filename1 || !e.filename2)
                 goto out;
-        if (!is_delete)
-                entry = kmalloc(sizeof(*entry), GFP_NOFS);
         if (mutex_lock_interruptible(&tomoyo_policy_lock))
                 goto out;
         list_for_each_entry_rcu(ptr, &domain->acl_info_list, list) {
@@ -922,8 +910,8 @@ static int tomoyo_update_path2_acl(const u8 type, const char *filename1,
                         container_of(ptr, struct tomoyo_path2_acl, head);
                 if (ptr->type != TOMOYO_TYPE_PATH2_ACL)
                         continue;
-                if (acl->filename1 != saved_filename1 ||
-                    acl->filename2 != saved_filename2)
+                if (acl->filename1 != e.filename1 ||
+                    acl->filename2 != e.filename2)
                         continue;
                 if (is_delete)
                         acl->perm &= ~perm;
@@ -932,22 +920,19 @@ static int tomoyo_update_path2_acl(const u8 type, const char *filename1,
                 error = 0;
                 break;
         }
-        if (!is_delete && error && tomoyo_memory_ok(entry)) {
-                entry->head.type = TOMOYO_TYPE_PATH2_ACL;
-                entry->perm = perm;
-                entry->filename1 = saved_filename1;
-                saved_filename1 = NULL;
-                entry->filename2 = saved_filename2;
-                saved_filename2 = NULL;
-                list_add_tail_rcu(&entry->head.list, &domain->acl_info_list);
-                entry = NULL;
-                error = 0;
+        if (!is_delete && error) {
+                struct tomoyo_path2_acl *entry =
+                        tomoyo_commit_ok(&e, sizeof(e));
+                if (entry) {
+                        list_add_tail_rcu(&entry->head.list,
+                                          &domain->acl_info_list);
+                        error = 0;
+                }
         }
         mutex_unlock(&tomoyo_policy_lock);
  out:
-        tomoyo_put_name(saved_filename1);
-        tomoyo_put_name(saved_filename2);
-        kfree(entry);
+        tomoyo_put_name(e.filename1);
+        tomoyo_put_name(e.filename2);
         return error;
 }