diff options
Diffstat (limited to 'net/rxrpc/rxgk_common.h')
| -rw-r--r-- | net/rxrpc/rxgk_common.h | 139 |
1 files changed, 139 insertions, 0 deletions
diff --git a/net/rxrpc/rxgk_common.h b/net/rxrpc/rxgk_common.h new file mode 100644 index 000000000000..7370a5655985 --- /dev/null +++ b/net/rxrpc/rxgk_common.h @@ -0,0 +1,139 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* Common bits for GSSAPI-based RxRPC security. + * + * Copyright (C) 2025 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include <crypto/krb5.h> +#include <crypto/skcipher.h> +#include <crypto/hash.h> + +/* + * Per-key number context. This is replaced when the connection is rekeyed. + */ +struct rxgk_context { + refcount_t usage; + unsigned int key_number; /* Rekeying number (goes in the rx header) */ + unsigned long flags; +#define RXGK_TK_NEEDS_REKEY 0 /* Set if this needs rekeying */ + unsigned long expiry; /* Expiration time of this key */ + long long bytes_remaining; /* Remaining Tx lifetime of this key */ + const struct krb5_enctype *krb5; /* RxGK encryption type */ + const struct rxgk_key *key; + + /* We need up to 7 keys derived from the transport key, but we don't + * actually need the transport key. Each key is derived by + * DK(TK,constant). + */ + struct crypto_aead *tx_enc; /* Transmission key */ + struct crypto_aead *rx_enc; /* Reception key */ + struct crypto_shash *tx_Kc; /* Transmission checksum key */ + struct crypto_shash *rx_Kc; /* Reception checksum key */ + struct crypto_aead *resp_enc; /* Response packet enc key */ +}; + +#define xdr_round_up(x) (round_up((x), sizeof(__be32))) +#define xdr_object_len(x) (4 + xdr_round_up(x)) + +/* + * rxgk_app.c + */ +int rxgk_yfs_decode_ticket(struct rxrpc_connection *conn, struct sk_buff *skb, + unsigned int ticket_offset, unsigned int ticket_len, + struct key **_key); +int rxgk_extract_token(struct rxrpc_connection *conn, struct sk_buff *skb, + unsigned int token_offset, unsigned int token_len, + struct key **_key); + +/* + * rxgk_kdf.c + */ +void rxgk_put(struct rxgk_context *gk); +struct rxgk_context *rxgk_generate_transport_key(struct rxrpc_connection *conn, + const struct rxgk_key *key, + unsigned int key_number, + gfp_t gfp); +int rxgk_set_up_token_cipher(const struct krb5_buffer *server_key, + struct crypto_aead **token_key, + unsigned int enctype, + const struct krb5_enctype **_krb5, + gfp_t gfp); + +/* + * Apply decryption and checksumming functions to part of an skbuff. The + * offset and length are updated to reflect the actual content of the encrypted + * region. + */ +static inline +int rxgk_decrypt_skb(const struct krb5_enctype *krb5, + struct crypto_aead *aead, + struct sk_buff *skb, + unsigned int *_offset, unsigned int *_len, + int *_error_code) +{ + struct scatterlist sg[16]; + size_t offset = 0, len = *_len; + int nr_sg, ret; + + sg_init_table(sg, ARRAY_SIZE(sg)); + nr_sg = skb_to_sgvec(skb, sg, *_offset, len); + if (unlikely(nr_sg < 0)) + return nr_sg; + + ret = crypto_krb5_decrypt(krb5, aead, sg, nr_sg, + &offset, &len); + switch (ret) { + case 0: + *_offset += offset; + *_len = len; + break; + case -EPROTO: + case -EBADMSG: + *_error_code = RXGK_SEALEDINCON; + break; + default: + break; + } + + return ret; +} + +/* + * Check the MIC on a region of an skbuff. The offset and length are updated + * to reflect the actual content of the secure region. + */ +static inline +int rxgk_verify_mic_skb(const struct krb5_enctype *krb5, + struct crypto_shash *shash, + const struct krb5_buffer *metadata, + struct sk_buff *skb, + unsigned int *_offset, unsigned int *_len, + u32 *_error_code) +{ + struct scatterlist sg[16]; + size_t offset = 0, len = *_len; + int nr_sg, ret; + + sg_init_table(sg, ARRAY_SIZE(sg)); + nr_sg = skb_to_sgvec(skb, sg, *_offset, len); + if (unlikely(nr_sg < 0)) + return nr_sg; + + ret = crypto_krb5_verify_mic(krb5, shash, metadata, sg, nr_sg, + &offset, &len); + switch (ret) { + case 0: + *_offset += offset; + *_len = len; + break; + case -EPROTO: + case -EBADMSG: + *_error_code = RXGK_SEALEDINCON; + break; + default: + break; + } + + return ret; +} |