From fffdaef2eb4a7333952e55cf97f1fc0fcc35f981 Mon Sep 17 00:00:00 2001 From: Kevin Coffman Date: Wed, 17 Mar 2010 13:03:06 -0400 Subject: gss_krb5: Add support for rc4-hmac encryption Add necessary changes to add kernel support for the rc4-hmac Kerberos encryption type used by Microsoft and described in rfc4757. Signed-off-by: Kevin Coffman Signed-off-by: Steve Dickson Signed-off-by: Trond Myklebust --- net/sunrpc/auth_gss/gss_krb5_mech.c | 96 +++++++++++++++++++++++++++++++++++++ 1 file changed, 96 insertions(+) (limited to 'net/sunrpc/auth_gss/gss_krb5_mech.c') diff --git a/net/sunrpc/auth_gss/gss_krb5_mech.c b/net/sunrpc/auth_gss/gss_krb5_mech.c index ef6b31349046..54eda5f0c58b 100644 --- a/net/sunrpc/auth_gss/gss_krb5_mech.c +++ b/net/sunrpc/auth_gss/gss_krb5_mech.c @@ -72,6 +72,27 @@ static const struct gss_krb5_enctype supported_gss_krb5_enctypes[] = { .cksumlength = 8, .keyed_cksum = 0, }, + /* + * RC4-HMAC + */ + { + .etype = ENCTYPE_ARCFOUR_HMAC, + .ctype = CKSUMTYPE_HMAC_MD5_ARCFOUR, + .name = "rc4-hmac", + .encrypt_name = "ecb(arc4)", + .cksum_name = "hmac(md5)", + .encrypt = krb5_encrypt, + .decrypt = krb5_decrypt, + .mk_key = NULL, + .signalg = SGN_ALG_HMAC_MD5, + .sealalg = SEAL_ALG_MICROSOFT_RC4, + .keybytes = 16, + .keylength = 16, + .blocksize = 1, + .conflen = 8, + .cksumlength = 8, + .keyed_cksum = 1, + }, /* * 3DES */ @@ -392,6 +413,79 @@ out_err: return -EINVAL; } +/* + * Note that RC4 depends on deriving keys using the sequence + * number or the checksum of a token. Therefore, the final keys + * cannot be calculated until the token is being constructed! + */ +static int +context_derive_keys_rc4(struct krb5_ctx *ctx) +{ + struct crypto_hash *hmac; + char sigkeyconstant[] = "signaturekey"; + int slen = strlen(sigkeyconstant) + 1; /* include null terminator */ + struct hash_desc desc; + struct scatterlist sg[1]; + int err; + + dprintk("RPC: %s: entered\n", __func__); + /* + * derive cksum (aka Ksign) key + */ + hmac = crypto_alloc_hash(ctx->gk5e->cksum_name, 0, CRYPTO_ALG_ASYNC); + if (IS_ERR(hmac)) { + dprintk("%s: error %ld allocating hash '%s'\n", + __func__, PTR_ERR(hmac), ctx->gk5e->cksum_name); + err = PTR_ERR(hmac); + goto out_err; + } + + err = crypto_hash_setkey(hmac, ctx->Ksess, ctx->gk5e->keylength); + if (err) + goto out_err_free_hmac; + + sg_init_table(sg, 1); + sg_set_buf(sg, sigkeyconstant, slen); + + desc.tfm = hmac; + desc.flags = 0; + + err = crypto_hash_init(&desc); + if (err) + goto out_err_free_hmac; + + err = crypto_hash_digest(&desc, sg, slen, ctx->cksum); + if (err) + goto out_err_free_hmac; + /* + * allocate hash, and blkciphers for data and seqnum encryption + */ + ctx->enc = crypto_alloc_blkcipher(ctx->gk5e->encrypt_name, 0, + CRYPTO_ALG_ASYNC); + if (IS_ERR(ctx->enc)) { + err = PTR_ERR(ctx->enc); + goto out_err_free_hmac; + } + + ctx->seq = crypto_alloc_blkcipher(ctx->gk5e->encrypt_name, 0, + CRYPTO_ALG_ASYNC); + if (IS_ERR(ctx->seq)) { + crypto_free_blkcipher(ctx->enc); + err = PTR_ERR(ctx->seq); + goto out_err_free_hmac; + } + + dprintk("RPC: %s: returning success\n", __func__); + + err = 0; + +out_err_free_hmac: + crypto_free_hash(hmac); +out_err: + dprintk("RPC: %s: returning %d\n", __func__, err); + return err; +} + static int context_derive_keys_new(struct krb5_ctx *ctx) { @@ -561,6 +655,8 @@ gss_import_v2_context(const void *p, const void *end, struct krb5_ctx *ctx) switch (ctx->enctype) { case ENCTYPE_DES3_CBC_RAW: return context_derive_keys_des3(ctx); + case ENCTYPE_ARCFOUR_HMAC: + return context_derive_keys_rc4(ctx); case ENCTYPE_AES128_CTS_HMAC_SHA1_96: case ENCTYPE_AES256_CTS_HMAC_SHA1_96: return context_derive_keys_new(ctx); -- cgit v1.2.3-59-g8ed1b