linux-ext4 - [PATCH] fscrypt: fix inline encryption not used on new files

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Date:   Tue, 10 Nov 2020 17:52:24 -0800
From:   Eric Biggers <ebiggers@...nel.org>
To:     linux-fscrypt@...r.kernel.org
Cc:     linux-ext4@...r.kernel.org, linux-f2fs-devel@...ts.sourceforge.net,
        Satya Tangirala <satyat@...gle.com>,
        Jaegeuk Kim <jaegeuk@...nel.org>
Subject: [PATCH] fscrypt: fix inline encryption not used on new files

From: Eric Biggers <ebiggers@...gle.com>

The new helper function fscrypt_prepare_new_inode() runs before
S_ENCRYPTED has been set on the new inode.  This accidentally made
fscrypt_select_encryption_impl() never enable inline encryption on newly
created files, due to its use of fscrypt_needs_contents_encryption()
which only returns true when S_ENCRYPTED is set.

Fix this by using S_ISREG() directly instead of
fscrypt_needs_contents_encryption(), analogous to what
select_encryption_mode() does.

I didn't notice this earlier because by design, the user-visible
behavior is the same (other than performance, potentially) regardless of
whether inline encryption is used or not.

Fixes: a992b20cd4ee ("fscrypt: add fscrypt_prepare_new_inode() and fscrypt_set_context()")
Signed-off-by: Eric Biggers <ebiggers@...gle.com>
---
 fs/crypto/inline_crypt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/crypto/inline_crypt.c b/fs/crypto/inline_crypt.c
index 89bffa82ed74a..c57bebfa48fea 100644
--- a/fs/crypto/inline_crypt.c
+++ b/fs/crypto/inline_crypt.c
@@ -74,7 +74,7 @@ int fscrypt_select_encryption_impl(struct fscrypt_info *ci)
 	int i;

 	/* The file must need contents encryption, not filenames encryption */
-	if (!fscrypt_needs_contents_encryption(inode))
+	if (!S_ISREG(inode->i_mode))
 		return 0;

 	/* The crypto mode must have a blk-crypto counterpart */

base-commit: 92cfcd030e4b1de11a6b1edb0840e55c26332d31
-- 
2.29.2