1 #include "os.h"
2 #include <libsec.h>
3
4 /* rfc2104 */
5 DigestState*
hmac_x(uchar * p,ulong len,uchar * key,ulong klen,uchar * digest,DigestState * s,DigestState * (* x)(uchar *,ulong,uchar *,DigestState *),int xlen)6 hmac_x(uchar *p, ulong len, uchar *key, ulong klen, uchar *digest, DigestState *s,
7 DigestState*(*x)(uchar*, ulong, uchar*, DigestState*), int xlen)
8 {
9 int i;
10 uchar pad[Hmacblksz+1], innerdigest[256];
11
12 if(xlen > sizeof(innerdigest))
13 return nil;
14 if(klen > Hmacblksz)
15 return nil;
16
17 /* first time through */
18 if(s == nil || s->seeded == 0){
19 memset(pad, 0x36, Hmacblksz);
20 pad[Hmacblksz] = 0;
21 for(i = 0; i < klen; i++)
22 pad[i] ^= key[i];
23 s = (*x)(pad, Hmacblksz, nil, s);
24 if(s == nil)
25 return nil;
26 }
27
28 s = (*x)(p, len, nil, s);
29 if(digest == nil)
30 return s;
31
32 /* last time through */
33 memset(pad, 0x5c, Hmacblksz);
34 pad[Hmacblksz] = 0;
35 for(i = 0; i < klen; i++)
36 pad[i] ^= key[i];
37 (*x)(nil, 0, innerdigest, s);
38 s = (*x)(pad, Hmacblksz, nil, nil);
39 (*x)(innerdigest, xlen, digest, s);
40 return nil;
41 }
42