Re: [PATCH v6 2/8] fscrypt: split and rename setup_file_encryption_key()

[Josef Bacik <josef@toxicpanda.com>]

On Tue, Aug 08, 2023 at 01:08:02PM -0400, Sweet Tea Dorminy wrote:
> At present, setup_file_encryption_key() does several things: it finds
> and locks the master key, and then calls into the appropriate functions
> to setup the prepared key for the fscrypt_info. The code is clearer to
> follow if these functions are divided.
> 
> Thus, move calling the appropriate file key setup function into a new
> fscrypt_setup_file_key() function. After the file key setup functions
> are moved, the remaining function can take a const fscrypt_info, and is
> renamed find_and_lock_master_key() to precisely describe its action.
> 
> Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
> ---
>  fs/crypto/keysetup.c | 77 ++++++++++++++++++++++++++++++--------------
>  1 file changed, 52 insertions(+), 25 deletions(-)
> 
> diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c
> index b89c32ad19fb..727d473b6b03 100644
> --- a/fs/crypto/keysetup.c
> +++ b/fs/crypto/keysetup.c
> @@ -386,6 +386,43 @@ static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci,
>  	return 0;
>  }
>  
> +/*
> + * Find or create the appropriate prepared key for an info.
> + */
> +static int fscrypt_setup_file_key(struct fscrypt_info *ci,
> +				  struct fscrypt_master_key *mk,
> +				  bool need_dirhash_key)
> +{
> +	int err;
> +
> +	if (!mk) {
> +		if (ci->ci_policy.version != FSCRYPT_POLICY_V1)
> +			return -ENOKEY;
> +
> +		/*
> +		 * As a legacy fallback for v1 policies, search for the key in
> +		 * the current task's subscribed keyrings too.  Don't move this
> +		 * to before the search of ->s_master_keys, since users
> +		 * shouldn't be able to override filesystem-level keys.
> +		 */
> +		return fscrypt_setup_v1_file_key_via_subscribed_keyrings(ci);
> +	}
> +
> +	switch (ci->ci_policy.version) {
> +	case FSCRYPT_POLICY_V1:
> +		err = fscrypt_setup_v1_file_key(ci, mk->mk_secret.raw);
> +		break;
> +	case FSCRYPT_POLICY_V2:
> +		err = fscrypt_setup_v2_file_key(ci, mk, need_dirhash_key);
> +		break;
> +	default:
> +		WARN_ON_ONCE(1);
> +		err = -EINVAL;
> +		break;
> +	}
> +	return err;
> +}
> +
>  /*
>   * Check whether the size of the given master key (@mk) is appropriate for the
>   * encryption settings which a particular file will use (@ci).
> @@ -426,7 +463,7 @@ static bool fscrypt_valid_master_key_size(const struct fscrypt_master_key *mk,
>  }
>  
>  /*
> - * Find the master key, then set up the inode's actual encryption key.
> + * Find and lock the master key.
>   *
>   * If the master key is found in the filesystem-level keyring, then it is
>   * returned in *mk_ret with its semaphore read-locked.  This is needed to ensure
> @@ -434,9 +471,8 @@ static bool fscrypt_valid_master_key_size(const struct fscrypt_master_key *mk,
>   * multiple tasks may race to create an fscrypt_info for the same inode), and to
>   * synchronize the master key being removed with a new inode starting to use it.
>   */
> -static int setup_file_encryption_key(struct fscrypt_info *ci,
> -				     bool need_dirhash_key,
> -				     struct fscrypt_master_key **mk_ret)
> +static int find_and_lock_master_key(const struct fscrypt_info *ci,
> +				    struct fscrypt_master_key **mk_ret)
>  {
>  	struct super_block *sb = ci->ci_inode->i_sb;
>  	struct fscrypt_key_specifier mk_spec;
> @@ -466,17 +502,19 @@ static int setup_file_encryption_key(struct fscrypt_info *ci,
>  			mk = fscrypt_find_master_key(sb, &mk_spec);
>  		}
>  	}
> +

Random newline, you can add

Reviewed-by: Josef Bacik <josef@toxicpanda.com>

once you fix it up.  Thanks,

Josef