diff options
| -rw-r--r-- | net/sunrpc/auth_gss/gss_krb5_crypto.c | 227 | ||||
| -rw-r--r-- | net/sunrpc/auth_gss/gss_krb5_internal.h | 6 | ||||
| -rw-r--r-- | net/sunrpc/auth_gss/gss_krb5_mech.c | 4 |
3 files changed, 237 insertions, 0 deletions
diff --git a/net/sunrpc/auth_gss/gss_krb5_crypto.c b/net/sunrpc/auth_gss/gss_krb5_crypto.c index 65c8b6982729..4f29216d414a 100644 --- a/net/sunrpc/auth_gss/gss_krb5_crypto.c +++ b/net/sunrpc/auth_gss/gss_krb5_crypto.c @@ -867,3 +867,230 @@ out_err: ret = GSS_S_FAILURE; return ret; } + +static u32 +krb5_etm_checksum(struct crypto_sync_skcipher *cipher, + struct crypto_ahash *tfm, const struct xdr_buf *body, + int body_offset, struct xdr_netobj *cksumout) +{ + unsigned int ivsize = crypto_sync_skcipher_ivsize(cipher); + struct ahash_request *req; + struct scatterlist sg[1]; + u8 *iv, *checksumdata; + int err = -ENOMEM; + + checksumdata = kmalloc(crypto_ahash_digestsize(tfm), GFP_KERNEL); + if (!checksumdata) + return GSS_S_FAILURE; + /* For RPCSEC, the "initial cipher state" is always all zeroes. */ + iv = kzalloc(ivsize, GFP_KERNEL); + if (!iv) + goto out_free_mem; + + req = ahash_request_alloc(tfm, GFP_KERNEL); + if (!req) + goto out_free_mem; + ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL); + err = crypto_ahash_init(req); + if (err) + goto out_free_ahash; + + sg_init_one(sg, iv, ivsize); + ahash_request_set_crypt(req, sg, NULL, ivsize); + err = crypto_ahash_update(req); + if (err) + goto out_free_ahash; + err = xdr_process_buf(body, body_offset, body->len - body_offset, + checksummer, req); + if (err) + goto out_free_ahash; + + ahash_request_set_crypt(req, NULL, checksumdata, 0); + err = crypto_ahash_final(req); + if (err) + goto out_free_ahash; + memcpy(cksumout->data, checksumdata, cksumout->len); + +out_free_ahash: + ahash_request_free(req); +out_free_mem: + kfree(iv); + kfree_sensitive(checksumdata); + return err ? GSS_S_FAILURE : GSS_S_COMPLETE; +} + +/** + * krb5_etm_encrypt - Encrypt using the RFC 8009 rules + * @kctx: Kerberos context + * @offset: starting offset of the payload, in bytes + * @buf: OUT: send buffer to contain the encrypted payload + * @pages: plaintext payload + * + * The main difference with aes_encrypt is that "The HMAC is + * calculated over the cipher state concatenated with the AES + * output, instead of being calculated over the confounder and + * plaintext. This allows the message receiver to verify the + * integrity of the message before decrypting the message." + * + * RFC 8009 Section 5: + * + * encryption function: as follows, where E() is AES encryption in + * CBC-CS3 mode, and h is the size of truncated HMAC (128 bits or + * 192 bits as described above). + * + * N = random value of length 128 bits (the AES block size) + * IV = cipher state + * C = E(Ke, N | plaintext, IV) + * H = HMAC(Ki, IV | C) + * ciphertext = C | H[1..h] + * + * This encryption formula provides AEAD EtM with key separation. + * + * Return values: + * %GSS_S_COMPLETE: Encryption successful + * %GSS_S_FAILURE: Encryption failed + */ +u32 +krb5_etm_encrypt(struct krb5_ctx *kctx, u32 offset, + struct xdr_buf *buf, struct page **pages) +{ + struct crypto_sync_skcipher *cipher, *aux_cipher; + struct crypto_ahash *ahash; + struct xdr_netobj hmac; + unsigned int conflen; + u8 *ecptr; + u32 err; + + if (kctx->initiate) { + cipher = kctx->initiator_enc; + aux_cipher = kctx->initiator_enc_aux; + ahash = kctx->initiator_integ; + } else { + cipher = kctx->acceptor_enc; + aux_cipher = kctx->acceptor_enc_aux; + ahash = kctx->acceptor_integ; + } + conflen = crypto_sync_skcipher_blocksize(cipher); + + offset += GSS_KRB5_TOK_HDR_LEN; + if (xdr_extend_head(buf, offset, conflen)) + return GSS_S_FAILURE; + krb5_make_confounder(buf->head[0].iov_base + offset, conflen); + offset -= GSS_KRB5_TOK_HDR_LEN; + + if (buf->tail[0].iov_base) { + ecptr = buf->tail[0].iov_base + buf->tail[0].iov_len; + } else { + buf->tail[0].iov_base = buf->head[0].iov_base + + buf->head[0].iov_len; + buf->tail[0].iov_len = 0; + ecptr = buf->tail[0].iov_base; + } + + memcpy(ecptr, buf->head[0].iov_base + offset, GSS_KRB5_TOK_HDR_LEN); + buf->tail[0].iov_len += GSS_KRB5_TOK_HDR_LEN; + buf->len += GSS_KRB5_TOK_HDR_LEN; + + err = krb5_cbc_cts_encrypt(cipher, aux_cipher, + offset + GSS_KRB5_TOK_HDR_LEN, + buf, pages); + if (err) + return GSS_S_FAILURE; + + hmac.data = buf->tail[0].iov_base + buf->tail[0].iov_len; + hmac.len = kctx->gk5e->cksumlength; + err = krb5_etm_checksum(cipher, ahash, + buf, offset + GSS_KRB5_TOK_HDR_LEN, &hmac); + if (err) + goto out_err; + buf->tail[0].iov_len += kctx->gk5e->cksumlength; + buf->len += kctx->gk5e->cksumlength; + + return GSS_S_COMPLETE; + +out_err: + return GSS_S_FAILURE; +} + +/** + * krb5_etm_decrypt - Decrypt using the RFC 8009 rules + * @kctx: Kerberos context + * @offset: starting offset of the ciphertext, in bytes + * @len: + * @buf: + * @headskip: OUT: the enctype's confounder length, in octets + * @tailskip: OUT: the enctype's HMAC length, in octets + * + * RFC 8009 Section 5: + * + * decryption function: as follows, where D() is AES decryption in + * CBC-CS3 mode, and h is the size of truncated HMAC. + * + * (C, H) = ciphertext + * (Note: H is the last h bits of the ciphertext.) + * IV = cipher state + * if H != HMAC(Ki, IV | C)[1..h] + * stop, report error + * (N, P) = D(Ke, C, IV) + * + * Return values: + * %GSS_S_COMPLETE: Decryption successful + * %GSS_S_BAD_SIG: computed HMAC != received HMAC + * %GSS_S_FAILURE: Decryption failed + */ +u32 +krb5_etm_decrypt(struct krb5_ctx *kctx, u32 offset, u32 len, + struct xdr_buf *buf, u32 *headskip, u32 *tailskip) +{ + struct crypto_sync_skcipher *cipher, *aux_cipher; + u8 our_hmac[GSS_KRB5_MAX_CKSUM_LEN]; + u8 pkt_hmac[GSS_KRB5_MAX_CKSUM_LEN]; + struct xdr_netobj our_hmac_obj; + struct crypto_ahash *ahash; + struct xdr_buf subbuf; + u32 ret = 0; + + if (kctx->initiate) { + cipher = kctx->acceptor_enc; + aux_cipher = kctx->acceptor_enc_aux; + ahash = kctx->acceptor_integ; + } else { + cipher = kctx->initiator_enc; + aux_cipher = kctx->initiator_enc_aux; + ahash = kctx->initiator_integ; + } + + /* Extract the ciphertext into @subbuf. */ + xdr_buf_subsegment(buf, &subbuf, offset + GSS_KRB5_TOK_HDR_LEN, + (len - offset - GSS_KRB5_TOK_HDR_LEN - + kctx->gk5e->cksumlength)); + + our_hmac_obj.data = our_hmac; + our_hmac_obj.len = kctx->gk5e->cksumlength; + ret = krb5_etm_checksum(cipher, ahash, &subbuf, 0, &our_hmac_obj); + if (ret) + goto out_err; + ret = read_bytes_from_xdr_buf(buf, len - kctx->gk5e->cksumlength, + pkt_hmac, kctx->gk5e->cksumlength); + if (ret) + goto out_err; + if (crypto_memneq(pkt_hmac, our_hmac, kctx->gk5e->cksumlength) != 0) { + ret = GSS_S_BAD_SIG; + goto out_err; + } + + ret = krb5_cbc_cts_decrypt(cipher, aux_cipher, 0, &subbuf); + if (ret) { + ret = GSS_S_FAILURE; + goto out_err; + } + + *headskip = crypto_sync_skcipher_blocksize(cipher); + *tailskip = kctx->gk5e->cksumlength; + return GSS_S_COMPLETE; + +out_err: + if (ret != GSS_S_BAD_SIG) + ret = GSS_S_FAILURE; + return ret; +} diff --git a/net/sunrpc/auth_gss/gss_krb5_internal.h b/net/sunrpc/auth_gss/gss_krb5_internal.h index 33abf9ee9508..fd2ae11c5067 100644 --- a/net/sunrpc/auth_gss/gss_krb5_internal.h +++ b/net/sunrpc/auth_gss/gss_krb5_internal.h @@ -108,4 +108,10 @@ u32 gss_krb5_aes_encrypt(struct krb5_ctx *kctx, u32 offset, u32 gss_krb5_aes_decrypt(struct krb5_ctx *kctx, u32 offset, u32 len, struct xdr_buf *buf, u32 *plainoffset, u32 *plainlen); +u32 krb5_etm_encrypt(struct krb5_ctx *kctx, u32 offset, struct xdr_buf *buf, + struct page **pages); + +u32 krb5_etm_decrypt(struct krb5_ctx *kctx, u32 offset, u32 len, + struct xdr_buf *buf, u32 *headskip, u32 *tailskip); + #endif /* _NET_SUNRPC_AUTH_GSS_KRB5_INTERNAL_H */ diff --git a/net/sunrpc/auth_gss/gss_krb5_mech.c b/net/sunrpc/auth_gss/gss_krb5_mech.c index b55897cac459..7fe39e47c84f 100644 --- a/net/sunrpc/auth_gss/gss_krb5_mech.c +++ b/net/sunrpc/auth_gss/gss_krb5_mech.c @@ -167,6 +167,8 @@ static const struct gss_krb5_enctype supported_gss_krb5_enctypes[] = { .import_ctx = gss_krb5_import_ctx_v2, .derive_key = krb5_kdf_hmac_sha2, + .encrypt = krb5_etm_encrypt, + .decrypt = krb5_etm_decrypt, .get_mic = gss_krb5_get_mic_v2, .verify_mic = gss_krb5_verify_mic_v2, @@ -192,6 +194,8 @@ static const struct gss_krb5_enctype supported_gss_krb5_enctypes[] = { .import_ctx = gss_krb5_import_ctx_v2, .derive_key = krb5_kdf_hmac_sha2, + .encrypt = krb5_etm_encrypt, + .decrypt = krb5_etm_decrypt, .get_mic = gss_krb5_get_mic_v2, .verify_mic = gss_krb5_verify_mic_v2, |