From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3E7213B0581; Thu, 30 Jul 2026 17:57:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785434226; cv=none; b=J9CpBUQM8gzJGyP3AHvE5RAEOPNit5nS+e/vyg6q+9MRQbBps6FGeCHXjo6RPrX1gJ+Uetoo4HjCcrEXTnWpXdbhwwMb9pFIsnAoUHBPljkb2VgocuWnp3A/RB8H5VzxQC0UC7V+nsx5Xd2rn3dMj/RFcHdgL0pfD4aq9GrFNxU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785434226; c=relaxed/simple; bh=r7O8QD+ivm+bvq9bs6znr99IcSljYbBNKpR59/rpEPU=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=QZKwdntr4ev9VLpLd2kEyeGUNr1zhkdW94ld19XOZKS7uRcD1LFK82T/W52U2gIPqRw1OFCVK7qxwuLYMz7tJvbRL6HQkGtfHhIlrRkH8oL/nKJjXTQpgNCgfLNvw4KOggenHt5R/+8ZgVXtF0vbbleAZDgR9y6sAYSYZ6nE+jQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Cy1H54IO; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Cy1H54IO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 67A4F1F00A3A; Thu, 30 Jul 2026 17:57:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785434224; bh=abhw088q6gYCQxNch23PgT1atsdpk0ME6d8Iyr32PiE=; h=From:To:Cc:Subject:Date; b=Cy1H54IOysiPRS76pS1Dp4whlY0kfSARu3n70I6mCwuid4tXNO/J2QUzQGw10enMm SbDBdkavAnVq00Jny93DwveIi5K9cRILVmqxAvPr7wYzFrtUjK/PV953TBeQtuoXAb LYFNmQKXQqrlbNGpf+xN/OyTPKp9xR3vBBxREo55Iej3GI6cmRSn9PEsMP87kc0Dqv tfG0tTEIFGBNTA77VhJ+CAHnyn0YCTV8eafhgSbBekvFM7QQK6cdNfeKcJ2ojvapVI bXd5pbFGLsZzZrgKkt0V2Vb0j3fBopS6evdnD9yI59mgu2237lcVLH3ksaLOS7ZNfI bVh7WIfmxo0vg== From: Eric Biggers To: linux-ext4@vger.kernel.org, Theodore Ts'o Cc: Andreas Dilger , Baokun Li , Jan Kara , Ojaswin Mujoo , Ritesh Harjani , Zhang Yi , Ira Weiny , linux-fscrypt@vger.kernel.org, linux-kernel@vger.kernel.org, Eric Biggers , Disha Goel , stable@vger.kernel.org Subject: [PATCH] ext4: don't enable DAX on new encrypted files Date: Thu, 30 Jul 2026 10:52:12 -0700 Message-ID: <20260730175212.36923-1-ebiggers@kernel.org> X-Mailer: git-send-email 2.55.0 Precedence: bulk X-Mailing-List: linux-ext4@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Currently, when a new encrypted regular file is created, the call to ext4_set_inode_flags(inode, init=true) in __ext4_new_inode() is made before EXT4_INODE_ENCRYPT is set. As a result, it can set S_DAX if the filesystem is mounted with "-o dax=always". EXT4_INODE_ENCRYPT then actually gets set a bit later in __ext4_new_inode(), when it calls fscrypt_set_context() which calls ext4_set_context(). ext4_set_context() sets EXT4_INODE_ENCRYPT and calls ext4_set_inode_flags(inode, init=false) to set S_ENCRYPTED too. This was intended to clear S_DAX as well. However, this was broken by commit 043546e46dc7 ("fs/ext4: Only change S_DAX on inode load"). This causes data written to the file to bypass encryption, also causing xfstests failures such as generic/548 (when "-o dax=always" is used). Fix this by simplifying the flow by making __ext4_new_inode() set EXT4_INODE_ENCRYPT earlier. This makes it take effect in ext4_set_inode_flags(inode, init=true), making S_DAX never be set. Similarly, make EXT4_STATE_MAY_INLINE_DATA never be set in the first place on new encrypted inodes. Then it doesn't need to be cleared. As a result of these simplifications, ext4_set_context() no longer needs to change inode flags or state when 'handle != NULL'. Remove that too. Reported-by: Disha Goel Reported-by: Ojaswin Mujoo Closes: https://lore.kernel.org/r/20260723085648.1500357-1-ojaswin@linux.ibm.com Fixes: 043546e46dc7 ("fs/ext4: Only change S_DAX on inode load") Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers --- fs/ext4/crypto.c | 40 ++++++++++++++++++++-------------------- fs/ext4/ialloc.c | 4 ++++ 2 files changed, 24 insertions(+), 20 deletions(-) diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c index f41f320f4437..3971986de028 100644 --- a/fs/ext4/crypto.c +++ b/fs/ext4/crypto.c @@ -144,7 +144,13 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len, if (inode->i_ino == EXT4_ROOT_INO) return -EPERM; - if (WARN_ON_ONCE(IS_DAX(inode) && i_size_read(inode))) + /* + * For new encrypted inodes, S_DAX is never set in the first place. + * + * For existing inodes, this is called only on empty directories. ext4 + * never sets S_DAX on directories. + */ + if (WARN_ON_ONCE(IS_DAX(inode))) return -EINVAL; if (ext4_test_inode_flag(inode, EXT4_INODE_DAX)) @@ -163,6 +169,14 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len, */ if (handle) { + /* + * __ext4_new_inode() should have already set the encrypt flag + * on the inode and avoided enabling inline data. + */ + if (WARN_ON_ONCE(!IS_ENCRYPTED(inode))) + return -EINVAL; + if (WARN_ON_ONCE(ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA))) + return -EINVAL; /* * Since the inode is new it is ok to pass the * XATTR_CREATE flag. This is necessary to match the @@ -170,21 +184,10 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len, * function with the credits allocated for the new * inode. */ - res = ext4_xattr_set_handle(handle, inode, - EXT4_XATTR_INDEX_ENCRYPTION, - EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, - ctx, len, XATTR_CREATE); - if (!res) { - ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT); - ext4_clear_inode_state(inode, - EXT4_STATE_MAY_INLINE_DATA); - /* - * Update inode->i_flags - S_ENCRYPTED will be enabled, - * S_DAX may be disabled - */ - ext4_set_inode_flags(inode, false); - } - return res; + return ext4_xattr_set_handle(handle, inode, + EXT4_XATTR_INDEX_ENCRYPTION, + EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, + ctx, len, XATTR_CREATE); } res = dquot_initialize(inode); @@ -205,10 +208,7 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len, ctx, len, 0); if (!res) { ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT); - /* - * Update inode->i_flags - S_ENCRYPTED will be enabled, - * S_DAX may be disabled - */ + /* Update inode->i_flags to set S_ENCRYPTED. */ ext4_set_inode_flags(inode, false); res = ext4_mark_inode_dirty(handle, inode); if (res) diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c index a40cb27f8116..a5831fc536db 100644 --- a/fs/ext4/ialloc.c +++ b/fs/ext4/ialloc.c @@ -997,6 +997,8 @@ struct inode *__ext4_new_inode(struct mnt_idmap *idmap, err = fscrypt_prepare_new_inode(dir, inode, &encrypt); if (err) goto out; + if (encrypt) + i_flags |= EXT4_ENCRYPT_FL; } err = dquot_initialize(inode); @@ -1306,6 +1308,8 @@ struct inode *__ext4_new_inode(struct mnt_idmap *idmap, ei->i_extra_isize = sbi->s_want_extra_isize; ei->i_inline_off = 0; if (ext4_has_feature_inline_data(sb) && + /* Encrypted inodes cannot have inline data */ + !(ei->i_flags & EXT4_ENCRYPT_FL) && (!(ei->i_flags & (EXT4_DAX_FL|EXT4_EA_INODE_FL)) || S_ISDIR(mode))) ext4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA); ret = inode; base-commit: f5098b6bae761e346ebcd9da7f95622c04733cff -- 2.55.0