1 /* This bit implements a simple API for using the SRP library over sockets. */
8 #include <sys/socket.h>
17 #define MSG_WAITALL 0x100 /* somehow not defined on my box */
21 /* This is called by the client with a connected socket, username, and
22 passphrase. pass can be NULL in which case the user is queried. */
24 int tsrp_client_authenticate(int s
, char *user
, char *pass
, TSRP_SESSION
*tsrp
)
27 unsigned char username
[MAXUSERLEN
+ 1], sbuf
[MAXSALTLEN
];
28 unsigned char msgbuf
[MAXPARAMLEN
+ 1], bbuf
[MAXPARAMLEN
];
29 unsigned char passbuf
[128], *skey
;
31 struct t_preconf
*tcp
; /* @@@ should go away */
32 struct t_num salt
, *A
, B
;
34 /* Send the username. */
41 memcpy(msgbuf
+ 1, user
, i
);
42 if (send(s
, msgbuf
, i
+ 1, 0) < 0) {
45 memcpy(username
, user
, i
);
48 /* Get the prime index and salt. */
50 i
= recv(s
, msgbuf
, 2, MSG_WAITALL
);
55 if (index
<= 0 || index
> t_getprecount()) {
58 tcp
= t_getpreparam(index
- 1);
60 if (salt
.len
> MAXSALTLEN
) {
64 i
= recv(s
, sbuf
, salt
.len
, MSG_WAITALL
);
69 /* @@@ t_clientopen() needs a variant that takes the index */
71 tc
= t_clientopen(username
, &tcp
->modulus
, &tcp
->generator
, &salt
);
76 /* Calculate A and send it to the server. */
78 A
= t_clientgenexp(tc
);
79 msgbuf
[0] = A
->len
- 1; /* len is max 256 */
80 memcpy(msgbuf
+ 1, A
->data
, A
->len
);
81 if (send(s
, msgbuf
, A
->len
+ 1, 0) < 0) {
85 /* Ask the user for the passphrase. */
88 t_getpass(passbuf
, sizeof(passbuf
), "Enter password:");
91 t_clientpasswd(tc
, pass
);
93 /* Get B from the server. */
95 i
= recv(s
, msgbuf
, 1, 0);
99 B
.len
= msgbuf
[0] + 1;
101 i
= recv(s
, bbuf
, B
.len
, MSG_WAITALL
);
106 /* Compute the session key. */
108 skey
= t_clientgetkey(tc
, &B
);
113 /* Send the response. */
115 if (send(s
, t_clientresponse(tc
), RESPONSE_LEN
, 0) < 0) {
119 /* Get the server's response. */
121 i
= recv(s
, msgbuf
, RESPONSE_LEN
, MSG_WAITALL
);
125 if (t_clientverify(tc
, msgbuf
) != 0) {
129 /* All done. Now copy the key and clean up. */
132 memcpy(tsrp
->username
, username
, strlen(username
) + 1);
133 memcpy(tsrp
->key
, skey
, SESSION_KEY_LEN
);
140 /* This is called by the server with a connected socket. */
142 int tsrp_server_authenticate(int s
, TSRP_SESSION
*tsrp
)
145 unsigned char username
[MAXUSERLEN
], *skey
;
146 unsigned char msgbuf
[MAXPARAMLEN
+ 1], abuf
[MAXPARAMLEN
];
150 /* Get the username. */
152 i
= recv(s
, msgbuf
, 1, 0);
157 i
= recv(s
, username
, j
, MSG_WAITALL
);
163 ts
= t_serveropen(username
);
168 /* Send the prime index and the salt. */
170 msgbuf
[0] = ts
->index
; /* max 256 primes... */
173 memcpy(msgbuf
+ 2, ts
->s
.data
, i
);
174 if (send(s
, msgbuf
, i
+ 2, 0) < 0) {
178 /* Calculate B while we're waiting. */
180 B
= t_servergenexp(ts
);
182 /* Get A from the client. */
184 i
= recv(s
, msgbuf
, 1, 0);
188 A
.len
= msgbuf
[0] + 1;
190 i
= recv(s
, abuf
, A
.len
, MSG_WAITALL
);
197 msgbuf
[0] = B
->len
- 1;
198 memcpy(msgbuf
+ 1, B
->data
, B
->len
);
199 if (send(s
, msgbuf
, B
->len
+ 1, 0) < 0) {
203 /* Calculate the session key while we're waiting. */
205 skey
= t_servergetkey(ts
, &A
);
210 /* Get the response from the client. */
212 i
= recv(s
, msgbuf
, RESPONSE_LEN
, MSG_WAITALL
);
216 if (t_serververify(ts
, msgbuf
) != 0) {
220 /* Client authenticated. Now authenticate ourselves to the client. */
222 if (send(s
, t_serverresponse(ts
), RESPONSE_LEN
, 0) < 0) {
226 /* Copy the key and clean up. */
229 memcpy(tsrp
->username
, username
, strlen(username
) + 1);
230 memcpy(tsrp
->key
, skey
, SESSION_KEY_LEN
);
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