chanserv/chanservcrypto.c

   1 #include <stdio.h>
   2 #include <strings.h>
   3
   4 #include "chanserv.h"
   5 #include "../core/error.h"
   6 #include "../lib/prng.h"
   7 #include "../lib/sha1.h"
   8 #include "../lib/sha2.h"
   9 #include "../lib/md5.h"
  10 #include "../lib/hmac.h"
  11
  12 prngctx rng;
  13
  14 void chanservcryptoinit(void) {
  15   int ret;
  16
  17   FILE *e = fopen(ENTROPYSOURCE, "rb");
  18   if(!e) {
  19     Error("chanserv",ERR_STOP,"Unable to open entropy source.");
  20     /* shouldn't be running now... */
  21   }
  22
  23   ret = fread(rng.randrsl, 1, sizeof(rng.randrsl), e);
  24   fclose(e);
  25
  26   if(ret != sizeof(rng.randrsl)) {
  27     Error("chanserv",ERR_STOP,"Unable to read entropy.");
  28     /* shouldn't be running now... */
  29   }
  30
  31   prnginit(&rng, 1);
  32 }
  33
  34 ub4 cs_getrandint(void) {
  35   return prng(&rng);
  36 }
  37
  38 void cs_getrandbytes(unsigned char *buf, size_t bytes) {
  39   for(;bytes>0;bytes-=4,buf+=4) {
  40     ub4 b = cs_getrandint();
  41     memcpy(buf, &b, 4);
  42   }
  43 }
  44
  45 const char *cs_cralgorithmlist(void) {
  46   return "HMAC-MD5 HMAC-SHA-1 HMAC-SHA-256";
  47 }
  48
  49 int crsha1(char *username, const char *password, const char *challenge, const char *response) {
  50   char buf[1024];
  51
  52   SHA1_CTX ctx;
  53   unsigned char digest[20];
  54   char hexbuf[sizeof(digest) * 2 + 1];
  55   hmacsha1 hmac;
  56
  57   /* not sure how this helps but the RFC says to do it... */
  58   SHA1Init(&ctx);
  59   SHA1Update(&ctx, (unsigned char *)password, strlen(password));
  60   SHA1Final(digest, &ctx);
  61
  62   snprintf(buf, sizeof(buf), "%s:%s", username, hmac_printhex(digest, hexbuf, sizeof(digest)));
  63
  64   SHA1Init(&ctx);
  65   SHA1Update(&ctx, (unsigned char *)buf, strlen(buf));
  66   SHA1Final(digest, &ctx);
  67
  68   hmacsha1_init(&hmac, (unsigned char *)hmac_printhex(digest, hexbuf, sizeof(digest)), sizeof(digest) * 2);
  69   hmacsha1_update(&hmac, (unsigned char *)challenge, strlen(challenge));
  70   hmacsha1_final(&hmac, digest);
  71
  72   hmac_printhex(digest, hexbuf, sizeof(digest));
  73
  74   if(!strcasecmp(hmac_printhex(digest, hexbuf, sizeof(digest)), response))
  75     return 1;
  76
  77   return 0;
  78 }
  79
  80 int crsha256(char *username, const char *password, const char *challenge, const char *response) {
  81   char buf[1024];
  82
  83   SHA256_CTX ctx;
  84   unsigned char digest[32];
  85   char hexbuf[sizeof(digest) * 2 + 1];
  86   hmacsha256 hmac;
  87
  88   /* not sure how this helps but the RFC says to do it... */
  89   SHA256_Init(&ctx);
  90   SHA256_Update(&ctx, (unsigned char *)password, strlen(password));
  91   SHA256_Final(digest, &ctx);
  92
  93   snprintf(buf, sizeof(buf), "%s:%s", username, hmac_printhex(digest, hexbuf, sizeof(digest)));
  94
  95   SHA256_Init(&ctx);
  96   SHA256_Update(&ctx, (unsigned char *)buf, strlen(buf));
  97   SHA256_Final(digest, &ctx);
  98
  99   hmacsha256_init(&hmac, (unsigned char *)hmac_printhex(digest, hexbuf, sizeof(digest)), sizeof(digest) * 2);
 100   hmacsha256_update(&hmac, (unsigned char *)challenge, strlen(challenge));
 101   hmacsha256_final(&hmac, digest);
 102
 103   if(!strcasecmp(hmac_printhex(digest, hexbuf, sizeof(digest)), response))
 104     return 1;
 105
 106   return 0;
 107 }
 108
 109 int crmd5(char *username, const char *password, const char *challenge, const char *response) {
 110   char buf[1024];
 111
 112   MD5Context ctx;
 113   unsigned char digest[16];
 114   char hexbuf[sizeof(digest) * 2 + 1];
 115   hmacmd5 hmac;
 116
 117   /* not sure how this helps but the RFC says to do it... */
 118   MD5Init(&ctx);
 119   MD5Update(&ctx, (unsigned char *)password, strlen(password));
 120   MD5Final(digest, &ctx);
 121
 122   snprintf(buf, sizeof(buf), "%s:%s", username, hmac_printhex(digest, hexbuf, sizeof(digest)));
 123
 124   MD5Init(&ctx);
 125   MD5Update(&ctx, (unsigned char *)buf, strlen(buf));
 126   MD5Final(digest, &ctx);
 127
 128   hmacmd5_init(&hmac, (unsigned char *)hmac_printhex(digest, hexbuf, sizeof(digest)), sizeof(digest) * 2);
 129   hmacmd5_update(&hmac, (unsigned char *)challenge, strlen(challenge));
 130   hmacmd5_final(&hmac, digest);
 131
 132   if(!strcasecmp(hmac_printhex(digest, hexbuf, sizeof(digest)), response))
 133     return 1;
 134
 135   return 0;
 136 }
 137
 138 CRAlgorithm cs_cralgorithm(const char *algorithm) {
 139   if(!strcasecmp(algorithm, "hmac-sha-1"))
 140     return crsha1;
 141
 142   if(!strcasecmp(algorithm, "hmac-sha-256"))
 143     return crsha256;
 144
 145   if(!strcasecmp(algorithm, "hmac-md5"))
 146     return crmd5;
 147
 148   return 0;
 149 }
 150
 151 char *cs_calcchallenge(const unsigned char *entropy) {
 152   unsigned char buf[20];
 153   static char hexbuf[sizeof(buf) * 2 + 1];
 154   SHA1_CTX ctx;
 155
 156   SHA1Init(&ctx);
 157   /* we can maybe add a salt here in the future */
 158   SHA1Update(&ctx, entropy, ENTROPYLEN);
 159   SHA1Final(buf, &ctx);
 160
 161   hmac_printhex(buf, hexbuf, sizeof(buf));
 162
 163   return hexbuf;
 164 }
 165
 166 int cs_checkhashpass(const char *username, const char *password, const char *junk, const char *hash) {
 167   MD5Context ctx;
 168   unsigned char digest[16];
 169   char hexbuf[sizeof(digest) * 2 + 1], buf[512];
 170
 171   snprintf(buf, sizeof(buf), "%s %s%s%s", username, password, junk?" ":"", junk?junk:"");
 172
 173   MD5Init(&ctx);
 174   MD5Update(&ctx, (unsigned char *)buf, strlen(buf));
 175   MD5Final(digest, &ctx);
 176
 177   if(strcasecmp(hash, hmac_printhex(digest, hexbuf, sizeof(digest))))
 178     return 0;
 179
 180   return 1;
 181 }