Hi Eric, On Mon, Apr 23, 2018 at 09:50:15PM -0700, Eric Biggers wrote: > Hi Tycho, > > On Mon, Apr 23, 2018 at 07:03:19PM -0600, Tycho Andersen wrote: > > We're interested in getting rid of all of the stack allocated arrays in the > > kernel [1]. This patch simply hardcodes the iv length to match that of the > > hardcoded cipher. > > > > [1]: https://lkml.org/lkml/2018/3/7/621 > > > > v2: hardcode the length of the nonce to be the GCM AES IV length, and do a > > sanity check in init(), Eric Biggers > > > > Signed-off-by: Tycho Andersen <[email protected]> > > CC: David Howells <[email protected]> > > CC: James Morris <[email protected]> > > CC: "Serge E. Hallyn" <[email protected]> > > CC: Jason A. Donenfeld <[email protected]> > > CC: Eric Biggers <[email protected]> > > --- > > security/keys/big_key.c | 9 ++++++++- > > 1 file changed, 8 insertions(+), 1 deletion(-) > > > > diff --git a/security/keys/big_key.c b/security/keys/big_key.c > > index 933623784ccd..75c46786a166 100644 > > --- a/security/keys/big_key.c > > +++ b/security/keys/big_key.c > > @@ -22,6 +22,7 @@ > > #include <keys/user-type.h> > > #include <keys/big_key-type.h> > > #include <crypto/aead.h> > > +#include <crypto/gcm.h> > > > > struct big_key_buf { > > unsigned int nr_pages; > > @@ -109,7 +110,7 @@ static int big_key_crypt(enum big_key_op op, struct > > big_key_buf *buf, size_t dat > > * an .update function, so there's no chance we'll wind up reusing the > > * key to encrypt updated data. Simply put: one key, one encryption. > > */ > > - u8 zero_nonce[crypto_aead_ivsize(big_key_aead)]; > > + u8 zero_nonce[GCM_AES_IV_SIZE]; > > > > aead_req = aead_request_alloc(big_key_aead, GFP_KERNEL); > > if (!aead_req) > > @@ -425,6 +426,12 @@ static int __init big_key_init(void) > > pr_err("Can't alloc crypto: %d\n", ret); > > return ret; > > } > > + > > + if (unlikely(crypto_aead_ivsize(big_key_aead) != GCM_AES_IV_SIZE)) { > > + WARN(1, "big key algorithm changed?"); > > + return -EINVAL; > > + } > > + > > 'big_key_aead' needs to be freed on error. > > err = -EINVAL; > goto free_aead;
oof, yes, thanks. > Also how about defining the IV size next to the algorithm name? > Then all the algorithm details would be on adjacent lines: > > static const char big_key_alg_name[] = "gcm(aes)"; > #define BIG_KEY_IV_SIZE GCM_AES_IV_SIZE Sounds good, I'll fix both of these for v3. Cheers, Tycho
