From: Dmitry Monakhov Subject: [PATCH] ext4 crypto: handle ENOKEY correctly Date: Fri, 29 May 2015 20:39:03 +0400 Message-ID: <1432917543-26495-1-git-send-email-dmonakhov@openvz.org> Cc: tytso@mit.edu, Dmitry Monakhov To: linux-ext4@vger.kernel.org Return-path: Received: from mailhub.sw.ru ([195.214.232.25]:13463 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756432AbbE2QjS (ORCPT ); Fri, 29 May 2015 12:39:18 -0400 Sender: linux-ext4-owner@vger.kernel.org List-ID: Currently we try to hide ENOKEY inside ext4_get_encryption_info(), but it is not always correct. There are two class of callers ext4_get_encryption_info() 1) The one where we can ignore ENOKEY - ext4_setup_fname_crypto() - ext4_is_child_context_consistent_with_parent() 2) The one do care about any error because expect that ei->i_crypt_info will be initalized after ext4_get_encryption_info() succeed - ext4_file_mmap - ext4_file_open - ext4_inherit_context (key may becomes obsoleted, revoked, dead any time) So let's return ENOKEY from ext4_get_encryption_info() if necessery and let caller handle it correctly. #Test case (try to read encrypted file w/o key) keyctl clear @s mount $DEV /mnt cat > /mnt/enc_dir/enc_file #Result kernel BUG at fs/ext4/crypto.c:109 Call Trace: [] ext4_mpage_readpages+0x3ce/0x55d [] ? sched_clock_cpu+0x8c/0xa8 [] ext4_readpages+0x3c/0x3e [] __do_page_cache_readahead+0x164/0x1e6 [] ondemand_readahead+0x1ef/0x204 [] page_cache_sync_readahead+0x40/0x42 [] generic_file_read_iter+0x1b3/0x50d [] __vfs_read+0xb3/0xd2 [] vfs_read+0x8f/0xcf [] ? fdget_pos+0xd/0x18 [] SyS_read+0x5c/0x8c [] system_call_fastpath+0x12/0x76 Signed-off-by: Dmitry Monakhov --- fs/ext4/crypto_fname.c | 2 +- fs/ext4/crypto_key.c | 2 -- fs/ext4/crypto_policy.c | 4 ++-- 3 files changed, 3 insertions(+), 5 deletions(-) diff --git a/fs/ext4/crypto_fname.c b/fs/ext4/crypto_fname.c index e63dd29..9f450d3 100644 --- a/fs/ext4/crypto_fname.c +++ b/fs/ext4/crypto_fname.c @@ -265,7 +265,7 @@ int ext4_setup_fname_crypto(struct inode *inode) return 0; res = ext4_get_encryption_info(inode); - if (res < 0) + if (res < 0 && res != -ENOKEY) return res; ci = ei->i_crypt_info; diff --git a/fs/ext4/crypto_key.c b/fs/ext4/crypto_key.c index 858d7d6..db31972 100644 --- a/fs/ext4/crypto_key.c +++ b/fs/ext4/crypto_key.c @@ -191,8 +191,6 @@ int _ext4_get_encryption_info(struct inode *inode) crypt_info->ci_raw); out: if (res < 0) { - if (res == -ENOKEY) - res = 0; kmem_cache_free(ext4_crypt_info_cachep, crypt_info); } else { ei->i_crypt_info = crypt_info; diff --git a/fs/ext4/crypto_policy.c b/fs/ext4/crypto_policy.c index 683391f..db6e9f8 100644 --- a/fs/ext4/crypto_policy.c +++ b/fs/ext4/crypto_policy.c @@ -144,10 +144,10 @@ int ext4_is_child_context_consistent_with_parent(struct inode *parent, if (!ext4_encrypted_inode(child)) return 0; res = ext4_get_encryption_info(parent); - if (res) + if (res && res != -ENOKEY) return 0; res = ext4_get_encryption_info(child); - if (res) + if (res && res != -ENOKEY) return 0; parent_ci = EXT4_I(parent)->i_crypt_info; child_ci = EXT4_I(child)->i_crypt_info; -- 1.7.1