Previoulsy, fi->i_crypt_info was not covered by any lock, resulting in
memory leak.

This patch adds a rwsem to avoid leaking objects on i_crypt_info.

Signed-off-by: Jaegeuk Kim <jaeg...@kernel.org>
---
 fs/f2fs/crypto_key.c | 29 ++++++++++++++++++++++-------
 fs/f2fs/f2fs.h       |  1 +
 fs/f2fs/super.c      |  1 +
 3 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/fs/f2fs/crypto_key.c b/fs/f2fs/crypto_key.c
index 8a10569..a25b164 100644
--- a/fs/f2fs/crypto_key.c
+++ b/fs/f2fs/crypto_key.c
@@ -87,7 +87,7 @@ out:
        return res;
 }
 
-void f2fs_free_encryption_info(struct inode *inode)
+static void _f2fs_free_encryption_info(struct inode *inode)
 {
        struct f2fs_inode_info *fi = F2FS_I(inode);
        struct f2fs_crypt_info *ci = fi->i_crypt_info;
@@ -103,6 +103,13 @@ void f2fs_free_encryption_info(struct inode *inode)
        fi->i_crypt_info = NULL;
 }
 
+void f2fs_free_encryption_info(struct inode *inode)
+{
+       down_write(&F2FS_I(inode)->crypto_rwsem);
+       _f2fs_free_encryption_info(inode);
+       up_write(&F2FS_I(inode)->crypto_rwsem);
+}
+
 int _f2fs_get_encryption_info(struct inode *inode)
 {
        struct f2fs_inode_info *fi = F2FS_I(inode);
@@ -119,12 +126,13 @@ int _f2fs_get_encryption_info(struct inode *inode)
        if (res)
                return res;
 
-       if (fi->i_crypt_info) {
-               if (!fi->i_crypt_info->ci_keyring_key ||
-                       key_validate(fi->i_crypt_info->ci_keyring_key) == 0)
-                       return 0;
-               f2fs_free_encryption_info(inode);
+       down_read(&fi->crypto_rwsem);
+       if (fi->i_crypt_info && (!fi->i_crypt_info->ci_keyring_key ||
+                       key_validate(fi->i_crypt_info->ci_keyring_key) == 0)) {
+               up_read(&fi->crypto_rwsem);
+               return 0;
        }
+       up_read(&fi->crypto_rwsem);
 
        res = f2fs_getxattr(inode, F2FS_XATTR_INDEX_ENCRYPTION,
                                F2FS_XATTR_NAME_ENCRYPTION_CONTEXT,
@@ -187,8 +195,11 @@ out:
                        res = 0;
                kmem_cache_free(f2fs_crypt_info_cachep, crypt_info);
        } else {
+               down_write(&fi->crypto_rwsem);
+               _f2fs_free_encryption_info(inode);
                fi->i_crypt_info = crypt_info;
                crypt_info->ci_keyring_key = keyring_key;
+               up_write(&fi->crypto_rwsem);
                keyring_key = NULL;
        }
        if (keyring_key)
@@ -199,6 +210,10 @@ out:
 int f2fs_has_encryption_key(struct inode *inode)
 {
        struct f2fs_inode_info *fi = F2FS_I(inode);
+       int ret;
 
-       return (fi->i_crypt_info != NULL);
+       down_read(&fi->crypto_rwsem);
+       ret = (fi->i_crypt_info != NULL);
+       up_read(&fi->crypto_rwsem);
+       return ret;
 }
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 5119167..c44d7bf 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -431,6 +431,7 @@ struct f2fs_inode_info {
 #ifdef CONFIG_F2FS_FS_ENCRYPTION
        /* Encryption params */
        struct f2fs_crypt_info *i_crypt_info;
+       struct rw_semaphore crypto_rwsem;       /* lock for crypt_info */
 #endif
 };
 
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index bbeb6d7..137d1b7 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -418,6 +418,7 @@ static struct inode *f2fs_alloc_inode(struct super_block 
*sb)
 
 #ifdef CONFIG_F2FS_FS_ENCRYPTION
        fi->i_crypt_info = NULL;
+       init_rwsem(&fi->crypto_rwsem);
 #endif
        return &fi->vfs_inode;
 }
-- 
2.1.1


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