From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jaegeuk Kim Subject: [PATCH] f2fs crypto: add rwsem to avoid data races Date: Mon, 18 May 2015 22:36:41 -0700 Message-ID: <1432013801-39069-1-git-send-email-jaegeuk@kernel.org> Cc: Jaegeuk Kim To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Return-path: Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org 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 --- 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