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authorNicolai Stange <nstange@suse.de>2022-02-21 13:10:57 +0100
committerHerbert Xu <herbert@gondor.apana.org.au>2022-03-03 10:47:51 +1200
commitc8e8236cf71f1e808120804339d2c23dc304f9cd (patch)
treeba6fe743095564f7754416c9f38a500d7af75964 /crypto
parent209b7fc9c9249c400610cec1cbfba848f293f2e9 (diff)
crypto: dh - allow for passing NULL to the ffdheXYZ(dh)s' ->set_secret()
Ephemeral key generation can be requested from any of the ffdheXYZ(dh) variants' common ->set_secret() by passing it an (encoded) struct dh with the key parameter being unset, i.e. with ->key_size == 0. As the whole purpose of the ffdheXYZ(dh) templates is to fill in the group parameters as appropriate, they expect ->p and ->g to be unset in any input struct dh as well. This means that a user would have to encode an all-zeroes struct dh instance via crypto_dh_encode_key() when requesting ephemeral key generation from a ffdheXYZ(dh) instance, which is kind of pointless. Make dh_safe_prime_set_secret() to decode a struct dh from the supplied buffer only if the latter is non-NULL and initialize it with all zeroes otherwise. That is, it is now possible to call crypto_kpp_set_secret(tfm, NULL, 0); on any ffdheXYZ(dh) tfm for requesting ephemeral key generation. Signed-off-by: Nicolai Stange <nstange@suse.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto')
-rw-r--r--crypto/dh.c15
1 files changed, 8 insertions, 7 deletions
diff --git a/crypto/dh.c b/crypto/dh.c
index 869a0476e5e2..d0d24f615b2d 100644
--- a/crypto/dh.c
+++ b/crypto/dh.c
@@ -444,17 +444,18 @@ static int dh_safe_prime_set_secret(struct crypto_kpp *tfm, const void *buffer,
struct dh_safe_prime_instance_ctx *inst_ctx =
dh_safe_prime_instance_ctx(tfm);
struct dh_safe_prime_tfm_ctx *tfm_ctx = kpp_tfm_ctx(tfm);
- struct dh params;
+ struct dh params = {};
void *buf = NULL, *key = NULL;
unsigned int buf_size;
int err;
- err = __crypto_dh_decode_key(buffer, len, &params);
- if (err)
- return err;
-
- if (params.p_size || params.g_size)
- return -EINVAL;
+ if (buffer) {
+ err = __crypto_dh_decode_key(buffer, len, &params);
+ if (err)
+ return err;
+ if (params.p_size || params.g_size)
+ return -EINVAL;
+ }
params.p = inst_ctx->safe_prime->p;
params.p_size = inst_ctx->safe_prime->p_size;