2020-11-11 01:53:42

by Eric Biggers

Subject: [PATCH] fscrypt: fix inline encryption not used on new files

From: Eric Biggers <[email protected]>

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 <[email protected]>
---
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

2020-11-12 05:39:56

by Satya Tangirala

Subject: Re: [PATCH] fscrypt: fix inline encryption not used on new files

On Tue, Nov 10, 2020 at 05:52:24PM -0800, Eric Biggers wrote:
> From: Eric Biggers <[email protected]>
>
> 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 <[email protected]>
> ---
> 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
>
Looks good to me. Please feel free to add
Reviewed-by: Satya Tangirala <[email protected]>

2020-11-12 20:31:07

by Eric Biggers

Subject: Re: [PATCH] fscrypt: fix inline encryption not used on new files

On Tue, Nov 10, 2020 at 05:52:24PM -0800, Eric Biggers wrote:
> From: Eric Biggers <[email protected]>
>
> 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 <[email protected]>
> ---
> 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

Applied to fscrypt.git#for-stable for 5.10.

- Eric