[dm-devel] [PATCH 1/3] dm crypt: wipe keys string immediately after key is set
Mike Snitzer
snitzer at redhat.com
Thu Feb 3 15:52:45 UTC 2011
On Wed, Feb 02 2011 at 7:08pm -0500,
Milan Broz <mbroz at redhat.com> wrote:
> If the tfm key was set up correctly, do not keep another
> copy of key and immediately replace it with zero string.
>
> Signed-off-by: Milan Broz <mbroz at redhat.com>
> ---
> drivers/md/dm-crypt.c | 16 +++++++++++-----
> 1 files changed, 11 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
> index 4e054bd..d748433 100644
> --- a/drivers/md/dm-crypt.c
> +++ b/drivers/md/dm-crypt.c
> @@ -1331,20 +1331,26 @@ static int crypt_setkey_allcpus(struct crypt_config *cc)
>
> static int crypt_set_key(struct crypt_config *cc, char *key)
> {
> + int r = -EINVAL, key_string_len = strlen(key);
> +
> /* The key size may not be changed. */
> - if (cc->key_size != (strlen(key) >> 1))
> - return -EINVAL;
> + if (cc->key_size != (key_string_len >> 1))
> + goto out;
>
> /* Hyphen (which gives a key_size of zero) means there is no key. */
> if (!cc->key_size && strcmp(key, "-"))
> - return -EINVAL;
> + goto out;
>
> if (cc->key_size && crypt_decode_key(cc->key, key, cc->key_size) < 0)
> - return -EINVAL;
> + goto out;
>
> set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
>
> - return crypt_setkey_allcpus(cc);
> + r = crypt_setkey_allcpus(cc);
> +out:
> + /* Wipe hexa key string as soon as possible */
s/hexa/hex/ ?
> + memset(key, '0', key_string_len);
> + return r;
> }
>
> static int crypt_wipe_key(struct crypt_config *cc)
Acked-by: Mike Snitzer <snitzer at redhat.com>
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