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 
17 struct krb5_ctx;
18 
19 struct 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 
60 struct 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 
87 u32 gss_krb5_get_mic_v2(struct krb5_ctx *ctx, struct xdr_buf *text,
88 			struct xdr_netobj *token);
89 
90 u32 gss_krb5_verify_mic_v2(struct krb5_ctx *ctx, struct xdr_buf *message_buffer,
91 			   struct xdr_netobj *read_token);
92 
93 u32 gss_krb5_wrap_v2(struct krb5_ctx *kctx, int offset,
94 		     struct xdr_buf *buf, struct page **pages);
95 
96 u32 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 
106 int 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 
112 int 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 
118 int 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  */
krb5_derive_key(struct krb5_ctx * kctx,const struct xdr_netobj * inkey,struct xdr_netobj * outkey,u32 usage,u8 seed,gfp_t gfp_mask)138 static 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 
156 void krb5_make_confounder(u8 *p, int conflen);
157 
158 u32 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 
162 u32 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 
166 u32 krb5_encrypt(struct crypto_sync_skcipher *key, void *iv, void *in,
167 		 void *out, int length);
168 
169 u32 krb5_decrypt(struct crypto_sync_skcipher *key, void *iv, void *in,
170 		 void *out, int length);
171 
172 int xdr_extend_head(struct xdr_buf *buf, unsigned int base,
173 		    unsigned int shiftlen);
174 
175 int gss_encrypt_xdr_buf(struct crypto_sync_skcipher *tfm,
176 			struct xdr_buf *outbuf, int offset,
177 			struct page **pages);
178 
179 int gss_decrypt_xdr_buf(struct crypto_sync_skcipher *tfm,
180 			struct xdr_buf *inbuf, int offset);
181 
182 u32 gss_krb5_aes_encrypt(struct krb5_ctx *kctx, u32 offset,
183 			 struct xdr_buf *buf, struct page **pages);
184 
185 u32 gss_krb5_aes_decrypt(struct krb5_ctx *kctx, u32 offset, u32 len,
186 			 struct xdr_buf *buf, u32 *plainoffset, u32 *plainlen);
187 
188 u32 krb5_etm_encrypt(struct krb5_ctx *kctx, u32 offset, struct xdr_buf *buf,
189 		     struct page **pages);
190 
191 u32 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)
195 void krb5_nfold(u32 inbits, const u8 *in, u32 outbits, u8 *out);
196 const struct gss_krb5_enctype *gss_krb5_lookup_enctype(u32 etype);
197 int 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);
201 int krb5_cbc_cts_decrypt(struct crypto_sync_skcipher *cts_tfm,
202 			 struct crypto_sync_skcipher *cbc_tfm,
203 			 u32 offset, struct xdr_buf *buf);
204 u32 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