pki: Add ssh_pki_export_pubkey_rsa1().

1 files changed, 45 insertions, 0 deletions

diff --git a/src/pki_gcrypt.c b/src/pki_gcrypt.c
index cf770611..6f3cd957 100644
--- a/src/pki_gcrypt.c
+++ b/src/pki_gcrypt.c
@@ -1145,6 +1145,51 @@ fail:
     return NULL;
 }
 
+int pki_export_pubkey_rsa1(const ssh_key key,
+                           const char *host,
+                           char *rsa1,
+                           size_t rsa1_len)
+{
+    gcry_sexp_t sexp;
+    int rsa_size;
+    bignum b;
+    char *e, *n;
+
+    sexp = gcry_sexp_find_token(key->rsa, "e", 0);
+    if (sexp == NULL) {
+        return SSH_ERROR;
+    }
+    b = gcry_sexp_nth_mpi(sexp, 1, GCRYMPI_FMT_USG);
+    gcry_sexp_release(sexp);
+    if (b == NULL) {
+        return SSH_ERROR;
+    }
+    e = bignum_bn2dec(b);
+
+    sexp = gcry_sexp_find_token(key->rsa, "n", 0);
+    if (sexp == NULL) {
+        SAFE_FREE(e);
+        return SSH_ERROR;
+    }
+    b = gcry_sexp_nth_mpi(sexp, 1, GCRYMPI_FMT_USG);
+    gcry_sexp_release(sexp);
+    if (b == NULL) {
+        SAFE_FREE(e);
+        return SSH_ERROR;
+    }
+    n = bignum_bn2dec(b);
+
+    rsa_size = (gcry_pk_get_nbits(key->rsa) + 7) / 8;
+
+    snprintf(rsa1, rsa1_len,
+             "%s %d %s %s\n",
+             host, rsa_size << 3, e, n);
+    SAFE_FREE(e);
+    SAFE_FREE(n);
+
+    return SSH_OK;
+}
+
 ssh_string pki_signature_to_blob(const ssh_signature sig)
 {
     char buffer[40] = {0};