Hi Frederick, On Tue, Oct 04, 2022 at 04:29:27PM -0500, Frederick Lawler wrote: > We want to leverage keyring to store sensitive keys, and then use those > keys for symmetric encryption via the crypto API. Among the key types we > wish to support are: user, logon, encrypted, and trusted. > > User key types are already able to have their data copied to user space, > but logon does not support this. Further, trusted and encrypted keys will > return their encrypted data back to user space on read, which make them not > ideal for symmetric encryption. > > To support symmetric encryption for these key types, add a new > ALG_SET_KEY_BY_KEY_SERIAL setsockopt() option to the crypto API. This > allows users to pass a key_serial_t to the crypto API to perform > symmetric encryption. The behavior is the same as ALG_SET_KEY, but > the crypto key data is copied in kernel space from a keyring key, > which allows for the support of logon, encrypted, and trusted key types. > > Keyring keys must have the KEY_(POS|USR|GRP|OTH)_SEARCH permission set > to leverage this feature. This follows the asymmetric_key type where key > lookup calls eventually lead to keyring_search_rcu() without the > KEYRING_SEARCH_NO_CHECK_PERM flag set. > > Signed-off-by: Frederick Lawler <fred@xxxxxxxxxxxxxx> There was a similar patch several years ago by Ondrej Mosnacek: https://lore.kernel.org/linux-crypto/20190521100034.9651-1-omosnace@xxxxxxxxxx/T/#u Have you addressed all the feedback that was raised on that one? Two random nits below: > + *dest_len = key->datalen; > + *dest = kmalloc(*dest_len, GFP_KERNEL); > + if (!*dest) > + return -ENOMEM; > + > + memcpy(*dest, ukp->data, *dest_len); This should use kmemdup(). > + } else if (IS_ENABLED(CONFIG_ENCRYPTED_KEYS) && > + !strcmp(key->type->name, "encrypted")) { > + read_key = &read_key_type_encrypted; > + } else if (IS_ENABLED(CONFIG_TRUSTED_KEYS) && > + !strcmp(key->type->name, "trusted")) { > + read_key = &read_key_type_trusted; These need to use IS_REACHABLE(), not IS_ENABLED(). - Eric