release/src/router/dropbear/gensignkey.c

   1 #include "includes.h"
   2 #include "dbutil.h"
   3 #include "buffer.h"
   4 #include "ecdsa.h"
   5 #include "genrsa.h"
   6 #include "gendss.h"
   7 #include "signkey.h"
   8 #include "dbrandom.h"
   9
  10 #define RSA_DEFAULT_SIZE 2048
  11 #define DSS_DEFAULT_SIZE 1024
  12
  13 /* Returns DROPBEAR_SUCCESS or DROPBEAR_FAILURE */
  14 static int buf_writefile(buffer * buf, const char * filename) {
  15         int ret = DROPBEAR_FAILURE;
  16         int fd = -1;
  17
  18         fd = open(filename, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
  19         if (fd < 0) {
  20                 dropbear_log(LOG_ERR, "Couldn't create new file %s: %s",
  21                         filename, strerror(errno));
  22                 goto out;
  23         }
  24
  25         /* write the file now */
  26         while (buf->pos != buf->len) {
  27                 int len = write(fd, buf_getptr(buf, buf->len - buf->pos),
  28                                 buf->len - buf->pos);
  29                 if (errno == EINTR) {
  30                         continue;
  31                 }
  32                 if (len <= 0) {
  33                         dropbear_log(LOG_ERR, "Failed writing file %s: %s",
  34                                 filename, strerror(errno));
  35                         goto out;
  36                 }
  37                 buf_incrpos(buf, len);
  38         }
  39
  40         ret = DROPBEAR_SUCCESS;
  41
  42 out:
  43         if (fd >= 0) {
  44                 m_close(fd);
  45         }
  46         return ret;
  47 }
  48
  49 /* returns 0 on failure */
  50 static int get_default_bits(enum signkey_type keytype)
  51 {
  52         switch (keytype) {
  53 #ifdef DROPBEAR_RSA
  54             case DROPBEAR_SIGNKEY_RSA:
  55                                 return RSA_DEFAULT_SIZE;
  56 #endif
  57 #ifdef DROPBEAR_DSS
  58             case DROPBEAR_SIGNKEY_DSS:
  59                 return DSS_DEFAULT_SIZE;
  60 #endif
  61 #ifdef DROPBEAR_ECDSA
  62             case DROPBEAR_SIGNKEY_ECDSA_KEYGEN:
  63                 return ECDSA_DEFAULT_SIZE;
  64             case DROPBEAR_SIGNKEY_ECDSA_NISTP521:
  65                 return 521;
  66             case DROPBEAR_SIGNKEY_ECDSA_NISTP384:
  67                 return 384;
  68             case DROPBEAR_SIGNKEY_ECDSA_NISTP256:
  69                 return 256;
  70 #endif
  71             default:
  72                 return 0;
  73                 }
  74 }
  75
  76 int signkey_generate(enum signkey_type keytype, int bits, const char* filename)
  77 {
  78         sign_key * key = NULL;
  79         buffer *buf = NULL;
  80         int ret = DROPBEAR_FAILURE;
  81         if (bits == 0)
  82         {
  83                 bits = get_default_bits(keytype);
  84         }
  85
  86         /* now we can generate the key */
  87         key = new_sign_key();
  88
  89         seedrandom();
  90
  91         switch(keytype) {
  92 #ifdef DROPBEAR_RSA
  93                 case DROPBEAR_SIGNKEY_RSA:
  94                         key->rsakey = gen_rsa_priv_key(bits);
  95                         break;
  96 #endif
  97 #ifdef DROPBEAR_DSS
  98                 case DROPBEAR_SIGNKEY_DSS:
  99                         key->dsskey = gen_dss_priv_key(bits);
 100                         break;
 101 #endif
 102 #ifdef DROPBEAR_ECDSA
 103                 case DROPBEAR_SIGNKEY_ECDSA_KEYGEN:
 104                 case DROPBEAR_SIGNKEY_ECDSA_NISTP521:
 105                 case DROPBEAR_SIGNKEY_ECDSA_NISTP384:
 106                 case DROPBEAR_SIGNKEY_ECDSA_NISTP256:
 107                         {
 108                                 ecc_key *ecckey = gen_ecdsa_priv_key(bits);
 109                                 keytype = ecdsa_signkey_type(ecckey);
 110                                 *signkey_key_ptr(key, keytype) = ecckey;
 111                         }
 112                         break;
 113 #endif
 114                 default:
 115                         dropbear_exit("Internal error");
 116         }
 117
 118         seedrandom();
 119
 120         buf = buf_new(MAX_PRIVKEY_SIZE);
 121
 122         buf_put_priv_key(buf, key, keytype);
 123         sign_key_free(key);
 124         key = NULL;
 125         buf_setpos(buf, 0);
 126         ret = buf_writefile(buf, filename);
 127
 128         buf_burn(buf);
 129         buf_free(buf);
 130         buf = NULL;
 131         return ret;
 132 }