On Thu, Jun 15, 2017 at 01:41:29PM -0700, Michael Halcrow wrote:
> > static int validate_user_key(struct fscrypt_info *crypt_info,
> > struct fscrypt_context *ctx, u8 *raw_key,
> > - const char *prefix)
> > + const char *prefix, int min_keysize)
> > {
> > char *description;
> > struct key *keyring_key;
> > @@ -111,50 +116,60 @@ static int validate_user_key(struct fscrypt_info *crypt_info,
> > master_key = (struct fscrypt_key *)ukp->data;
> > BUILD_BUG_ON(FS_AES_128_ECB_KEY_SIZE != FS_KEY_DERIVATION_NONCE_SIZE);
> >
> > - if (master_key->size != FS_AES_256_XTS_KEY_SIZE) {
> > + if (master_key->size < min_keysize || master_key->size > FS_MAX_KEY_SIZE
> > + || master_key->size % AES_BLOCK_SIZE != 0) {
>
> I suggest validating the provided key size directly against the mode.
> Else, it looks to me that this code will accept a 128-bit key for
> AES-256.
>
It's doing that already; min_keysize depends on the mode.
Eric
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