On Thu, Apr 18, 2019 at 02:43:02PM -0700, Eric Biggers wrote: > From: Eric Biggers <[email protected]> > > GCM instances can be created by either the "gcm" template, which only > allows choosing the block cipher, e.g. "gcm(aes)"; or by "gcm_base", > which allows choosing the ctr and ghash implementations, e.g. > "gcm_base(ctr(aes-generic),ghash-generic)". > > However, a "gcm_base" instance prevents a "gcm" instance from being > registered using the same implementations. Nor will the instance be > found by lookups of "gcm". This can be used as a denial of service. > Moreover, "gcm_base" instances are never tested by the crypto > self-tests, even if there are compatible "gcm" tests. > > The root cause of these problems is that instances of the two templates > use different cra_names. Therefore, fix these problems by making > "gcm_base" instances set the same cra_name as "gcm" instances, e.g. > "gcm(aes)" instead of "gcm_base(ctr(aes-generic),ghash-generic)". > > This requires extracting the block cipher name from the name of the ctr > algorithm. It also requires starting to verify that the algorithms are > really ctr and ghash, not something else entirely. But it would be > bizarre if anyone were actually using non-gcm-compatible algorithms with > gcm_base, so this shouldn't break anyone in practice. > > Fixes: d00aa19b507b ("[CRYPTO] gcm: Allow block cipher parameter") > Cc: [email protected] > Signed-off-by: Eric Biggers <[email protected]> > --- > > Changed since v2: > - Leave checks for ctr cra_blocksize == 1 and ghash digestsize == 16. > > Changed since v1: > - Verify that ghash is really ghash (based on name). > - Improved commit message. > > crypto/gcm.c | 34 +++++++++++----------------------- > 1 file changed, 11 insertions(+), 23 deletions(-)
Patch applied. Thanks. -- Email: Herbert Xu <[email protected]> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
