1/* SPDX-License-Identifier: GPL-2.0 or BSD-3-Clause */
2/*
3 * SunRPC GSS Kerberos 5 mechanism internal definitions
4 *
5 * Copyright (c) 2022 Oracle and/or its affiliates.
6 */
7
8#ifndef _NET_SUNRPC_AUTH_GSS_KRB5_INTERNAL_H
9#define _NET_SUNRPC_AUTH_GSS_KRB5_INTERNAL_H
10
11/*
12 * The RFCs often specify payload lengths in bits. This helper
13 * converts a specified bit-length to the number of octets/bytes.
14 */
15#define BITS2OCTETS(x)	((x) / 8)
16
17struct krb5_ctx;
18
19struct gss_krb5_enctype {
20	const u32		etype;		/* encryption (key) type */
21	const u32		ctype;		/* checksum type */
22	const char		*name;		/* "friendly" name */
23	const char		*encrypt_name;	/* crypto encrypt name */
24	const char		*aux_cipher;	/* aux encrypt cipher name */
25	const char		*cksum_name;	/* crypto checksum name */
26	const u16		signalg;	/* signing algorithm */
27	const u16		sealalg;	/* sealing algorithm */
28	const u32		cksumlength;	/* checksum length */
29	const u32		keyed_cksum;	/* is it a keyed cksum? */
30	const u32		keybytes;	/* raw key len, in bytes */
31	const u32		keylength;	/* protocol key length, in octets */
32	const u32		Kc_length;	/* checksum subkey length, in octets */
33	const u32		Ke_length;	/* encryption subkey length, in octets */
34	const u32		Ki_length;	/* integrity subkey length, in octets */
35
36	int (*derive_key)(const struct gss_krb5_enctype *gk5e,
37			  const struct xdr_netobj *in,
38			  struct xdr_netobj *out,
39			  const struct xdr_netobj *label,
40			  gfp_t gfp_mask);
41	u32 (*encrypt)(struct krb5_ctx *kctx, u32 offset,
42		       struct xdr_buf *buf, struct page **pages);
43	u32 (*decrypt)(struct krb5_ctx *kctx, u32 offset, u32 len,
44		       struct xdr_buf *buf, u32 *headskip, u32 *tailskip);
45	u32 (*get_mic)(struct krb5_ctx *kctx, struct xdr_buf *text,
46		       struct xdr_netobj *token);
47	u32 (*verify_mic)(struct krb5_ctx *kctx, struct xdr_buf *message_buffer,
48			  struct xdr_netobj *read_token);
49	u32 (*wrap)(struct krb5_ctx *kctx, int offset,
50		    struct xdr_buf *buf, struct page **pages);
51	u32 (*unwrap)(struct krb5_ctx *kctx, int offset, int len,
52		      struct xdr_buf *buf, unsigned int *slack,
53		      unsigned int *align);
54};
55
56/* krb5_ctx flags definitions */
57#define KRB5_CTX_FLAG_INITIATOR         0x00000001
58#define KRB5_CTX_FLAG_ACCEPTOR_SUBKEY   0x00000004
59
60struct krb5_ctx {
61	int			initiate; /* 1 = initiating, 0 = accepting */
62	u32			enctype;
63	u32			flags;
64	const struct gss_krb5_enctype *gk5e; /* enctype-specific info */
65	struct crypto_sync_skcipher *enc;
66	struct crypto_sync_skcipher *seq;
67	struct crypto_sync_skcipher *acceptor_enc;
68	struct crypto_sync_skcipher *initiator_enc;
69	struct crypto_sync_skcipher *acceptor_enc_aux;
70	struct crypto_sync_skcipher *initiator_enc_aux;
71	struct crypto_ahash	*acceptor_sign;
72	struct crypto_ahash	*initiator_sign;
73	struct crypto_ahash	*initiator_integ;
74	struct crypto_ahash	*acceptor_integ;
75	u8			Ksess[GSS_KRB5_MAX_KEYLEN]; /* session key */
76	u8			cksum[GSS_KRB5_MAX_KEYLEN];
77	atomic_t		seq_send;
78	atomic64_t		seq_send64;
79	time64_t		endtime;
80	struct xdr_netobj	mech_used;
81};
82
83/*
84 * GSS Kerberos 5 mechanism Per-Message calls.
85 */
86
87u32 gss_krb5_get_mic_v2(struct krb5_ctx *ctx, struct xdr_buf *text,
88			struct xdr_netobj *token);
89
90u32 gss_krb5_verify_mic_v2(struct krb5_ctx *ctx, struct xdr_buf *message_buffer,
91			   struct xdr_netobj *read_token);
92
93u32 gss_krb5_wrap_v2(struct krb5_ctx *kctx, int offset,
94		     struct xdr_buf *buf, struct page **pages);
95
96u32 gss_krb5_unwrap_v2(struct krb5_ctx *kctx, int offset, int len,
97		       struct xdr_buf *buf, unsigned int *slack,
98		       unsigned int *align);
99
100/*
101 * Implementation internal functions
102 */
103
104/* Key Derivation Functions */
105
106int krb5_derive_key_v2(const struct gss_krb5_enctype *gk5e,
107		       const struct xdr_netobj *inkey,
108		       struct xdr_netobj *outkey,
109		       const struct xdr_netobj *label,
110		       gfp_t gfp_mask);
111
112int krb5_kdf_hmac_sha2(const struct gss_krb5_enctype *gk5e,
113		       const struct xdr_netobj *inkey,
114		       struct xdr_netobj *outkey,
115		       const struct xdr_netobj *in_constant,
116		       gfp_t gfp_mask);
117
118int krb5_kdf_feedback_cmac(const struct gss_krb5_enctype *gk5e,
119			   const struct xdr_netobj *inkey,
120			   struct xdr_netobj *outkey,
121			   const struct xdr_netobj *in_constant,
122			   gfp_t gfp_mask);
123
124/**
125 * krb5_derive_key - Derive a subkey from a protocol key
126 * @kctx: Kerberos 5 context
127 * @inkey: base protocol key
128 * @outkey: OUT: derived key
129 * @usage: key usage value
130 * @seed: key usage seed (one octet)
131 * @gfp_mask: memory allocation control flags
132 *
133 * Caller sets @outkey->len to the desired length of the derived key.
134 *
135 * On success, returns 0 and fills in @outkey. A negative errno value
136 * is returned on failure.
137 */
138static inline int krb5_derive_key(struct krb5_ctx *kctx,
139				  const struct xdr_netobj *inkey,
140				  struct xdr_netobj *outkey,
141				  u32 usage, u8 seed, gfp_t gfp_mask)
142{
143	const struct gss_krb5_enctype *gk5e = kctx->gk5e;
144	u8 label_data[GSS_KRB5_K5CLENGTH];
145	struct xdr_netobj label = {
146		.len	= sizeof(label_data),
147		.data	= label_data,
148	};
149	__be32 *p = (__be32 *)label_data;
150
151	*p = cpu_to_be32(usage);
152	label_data[4] = seed;
153	return gk5e->derive_key(gk5e, inkey, outkey, &label, gfp_mask);
154}
155
156void krb5_make_confounder(u8 *p, int conflen);
157
158u32 make_checksum(struct krb5_ctx *kctx, char *header, int hdrlen,
159		  struct xdr_buf *body, int body_offset, u8 *cksumkey,
160		  unsigned int usage, struct xdr_netobj *cksumout);
161
162u32 gss_krb5_checksum(struct crypto_ahash *tfm, char *header, int hdrlen,
163		      const struct xdr_buf *body, int body_offset,
164		      struct xdr_netobj *cksumout);
165
166u32 krb5_encrypt(struct crypto_sync_skcipher *key, void *iv, void *in,
167		 void *out, int length);
168
169u32 krb5_decrypt(struct crypto_sync_skcipher *key, void *iv, void *in,
170		 void *out, int length);
171
172int xdr_extend_head(struct xdr_buf *buf, unsigned int base,
173		    unsigned int shiftlen);
174
175int gss_encrypt_xdr_buf(struct crypto_sync_skcipher *tfm,
176			struct xdr_buf *outbuf, int offset,
177			struct page **pages);
178
179int gss_decrypt_xdr_buf(struct crypto_sync_skcipher *tfm,
180			struct xdr_buf *inbuf, int offset);
181
182u32 gss_krb5_aes_encrypt(struct krb5_ctx *kctx, u32 offset,
183			 struct xdr_buf *buf, struct page **pages);
184
185u32 gss_krb5_aes_decrypt(struct krb5_ctx *kctx, u32 offset, u32 len,
186			 struct xdr_buf *buf, u32 *plainoffset, u32 *plainlen);
187
188u32 krb5_etm_encrypt(struct krb5_ctx *kctx, u32 offset, struct xdr_buf *buf,
189		     struct page **pages);
190
191u32 krb5_etm_decrypt(struct krb5_ctx *kctx, u32 offset, u32 len,
192		     struct xdr_buf *buf, u32 *headskip, u32 *tailskip);
193
194#if IS_ENABLED(CONFIG_KUNIT)
195void krb5_nfold(u32 inbits, const u8 *in, u32 outbits, u8 *out);
196const struct gss_krb5_enctype *gss_krb5_lookup_enctype(u32 etype);
197int krb5_cbc_cts_encrypt(struct crypto_sync_skcipher *cts_tfm,
198			 struct crypto_sync_skcipher *cbc_tfm, u32 offset,
199			 struct xdr_buf *buf, struct page **pages,
200			 u8 *iv, unsigned int ivsize);
201int krb5_cbc_cts_decrypt(struct crypto_sync_skcipher *cts_tfm,
202			 struct crypto_sync_skcipher *cbc_tfm,
203			 u32 offset, struct xdr_buf *buf);
204u32 krb5_etm_checksum(struct crypto_sync_skcipher *cipher,
205		      struct crypto_ahash *tfm, const struct xdr_buf *body,
206		      int body_offset, struct xdr_netobj *cksumout);
207#endif
208
209#endif /* _NET_SUNRPC_AUTH_GSS_KRB5_INTERNAL_H */
210