openssl: Add support for RFC4716 keys
[paraslash.git] / gcrypt.c
index abc3272a6490ca541f1385c992c6ee99d5ef7986..dbe4900862fef83a552d9c60d9ac21d4c8253d5e 100644 (file)
--- a/gcrypt.c
+++ b/gcrypt.c
@@ -106,64 +106,6 @@ static const char *gcrypt_strerror(gcry_error_t gret)
        return gcry_strerror(gcry_err_code(gret));
 }
 
-/** Private keys start with this header. */
-#define PRIVATE_KEY_HEADER "-----BEGIN RSA PRIVATE KEY-----"
-/** Private keys end with this footer. */
-#define PRIVATE_KEY_FOOTER "-----END RSA PRIVATE KEY-----"
-
-static int decode_key(const char *key_file, unsigned char **result,
-               size_t *blob_size)
-{
-       int ret, ret2, i, j;
-       void *map;
-       size_t map_size, key_size;
-       unsigned char *blob = NULL;
-       char *begin, *footer, *key;
-
-       ret = mmap_full_file(key_file, O_RDONLY, &map, &map_size, NULL);
-       if (ret < 0)
-               goto out;
-       ret = -E_KEY_MARKER;
-       if (strncmp(map, PRIVATE_KEY_HEADER, strlen(PRIVATE_KEY_HEADER)))
-               goto unmap;
-       footer = strstr(map, PRIVATE_KEY_FOOTER);
-       ret = -E_KEY_MARKER;
-       if (!footer)
-               goto unmap;
-       begin = map + strlen(PRIVATE_KEY_HEADER);
-       /* skip whitespace at the beginning */
-       for (; begin < footer; begin++) {
-               if (para_isspace(*begin))
-                       continue;
-               break;
-       }
-       ret = -E_KEY_MARKER;
-       if (begin >= footer)
-               goto unmap;
-
-       key_size = footer - begin;
-       key = para_malloc(key_size + 1);
-       for (i = 0, j = 0; begin + i < footer; i++) {
-               if (para_isspace(begin[i]))
-                       continue;
-               key[j++] = begin[i];
-       }
-       key[j] = '\0';
-       ret = base64_decode(key, j, (char **)&blob, blob_size);
-       free(key);
-unmap:
-       ret2 = para_munmap(map, map_size);
-       if (ret >= 0 && ret2 < 0)
-               ret = ret2;
-       if (ret < 0) {
-               free(blob);
-               blob = NULL;
-       }
-out:
-       *result = blob;
-       return ret;
-}
-
 /** ASN Types and their code. */
 enum asn1_types {
        /** The next object is an integer. */
@@ -208,7 +150,7 @@ static inline int get_long_form_num_length_bytes(unsigned char c)
  * bitsp because the latter does not include the ASN.1 prefix and a leading
  * zero is not considered as an additional byte for the number of bits.
  */
-static int read_bignum(unsigned char *start, unsigned char *end, gcry_mpi_t *bn,
+static int read_pem_bignum(unsigned char *start, unsigned char *end, gcry_mpi_t *bn,
                unsigned *bitsp)
 {
        int i, bn_size;
@@ -256,7 +198,55 @@ static int read_bignum(unsigned char *start, unsigned char *end, gcry_mpi_t *bn,
        return cp - start;
 }
 
-static int find_privkey_bignum_offset(const unsigned char *data, int len)
+struct rsa_params {
+       gcry_mpi_t n, e, d, p, q, u;
+};
+
+static int read_pem_rsa_params(unsigned char *start, unsigned char *end,
+               struct rsa_params *p)
+{
+       unsigned char *cp = start;
+       unsigned bits;
+       int ret;
+
+       ret = read_pem_bignum(cp, end, &p->n, &bits);
+       if (ret < 0)
+               return ret;
+       cp += ret;
+       ret = read_pem_bignum(cp, end, &p->e, NULL);
+       if (ret < 0)
+               goto release_n;
+       cp += ret;
+       ret = read_pem_bignum(cp, end, &p->d, NULL);
+       if (ret < 0)
+               goto release_e;
+       cp += ret;
+       ret = read_pem_bignum(cp, end, &p->p, NULL);
+       if (ret < 0)
+               goto release_d;
+       cp += ret;
+       ret = read_pem_bignum(cp, end, &p->q, NULL);
+       if (ret < 0)
+               goto release_p;
+       cp += ret;
+       ret = read_pem_bignum(cp, end, &p->u, NULL);
+       if (ret < 0)
+               goto release_q;
+       return bits;
+release_q:
+       gcry_mpi_release(p->q);
+release_p:
+       gcry_mpi_release(p->p);
+release_d:
+       gcry_mpi_release(p->d);
+release_e:
+       gcry_mpi_release(p->e);
+release_n:
+       gcry_mpi_release(p->n);
+       return ret;
+}
+
+static int find_pem_bignum_offset(const unsigned char *data, int len)
 {
        const unsigned char *p = data, *end = data + len;
 
@@ -288,90 +278,131 @@ static int find_privkey_bignum_offset(const unsigned char *data, int len)
        return p - data;
 }
 
-static int get_private_key(const char *key_file, struct asymmetric_key **result)
+static int read_openssh_bignum(unsigned char *start, unsigned char *end,
+               gcry_mpi_t *bn, unsigned *bitsp)
 {
-       gcry_mpi_t n = NULL, e = NULL, d = NULL, p = NULL, q = NULL,
-               u = NULL;
-       unsigned char *blob, *cp, *end;
-       int ret;
-       unsigned bits;
        gcry_error_t gret;
-       size_t erroff, blob_size;
-       gcry_sexp_t sexp;
-       struct asymmetric_key *key;
+       size_t nscanned;
+       unsigned bits;
 
-       *result = NULL;
-       ret = decode_key(key_file, &blob, &blob_size);
-       if (ret < 0)
-               return ret;
-       end = blob + blob_size;
-       ret = find_privkey_bignum_offset(blob, blob_size);
-       if (ret < 0)
-               goto free_blob;
-       PARA_INFO_LOG("reading RSA params at offset %d\n", ret);
-       cp = blob + ret;
+       gret = gcry_mpi_scan(bn, GCRYMPI_FMT_SSH, start, end - start, &nscanned);
+       if (gret) {
+               PARA_ERROR_LOG("gcry_mpi_scan: %s\n",
+                       gcry_strerror(gcry_err_code(gret)));
+               return -E_MPI_SCAN;
+       }
+       bits = (nscanned - 4 - (start[4] == '\0')) * 8;
+       if (bitsp)
+               *bitsp = bits;
+       PARA_DEBUG_LOG("scanned %u-bit bignum\n", bits);
+       return nscanned;
+}
 
-       ret = read_bignum(cp, end, &n, &bits);
+static int read_openssh_rsa_params(unsigned char *start, unsigned char *end,
+               struct rsa_params *p)
+{
+       unsigned char *cp = start;
+       unsigned bits;
+       int ret;
+
+       ret = read_openssh_bignum(cp, end, &p->n, &bits);
        if (ret < 0)
-               goto free_blob;
+               return ret;
        cp += ret;
-
-       ret = read_bignum(cp, end, &e, NULL);
+       ret = read_openssh_bignum(cp, end, &p->e, NULL);
        if (ret < 0)
                goto release_n;
        cp += ret;
-
-       ret = read_bignum(cp, end, &d, NULL);
+       ret = read_openssh_bignum(cp, end, &p->d, NULL);
        if (ret < 0)
                goto release_e;
        cp += ret;
-
-       ret = read_bignum(cp, end, &p, NULL);
+       ret = read_openssh_bignum(cp, end, &p->u, NULL);
        if (ret < 0)
                goto release_d;
        cp += ret;
-
-       ret = read_bignum(cp, end, &q, NULL);
+       ret = read_openssh_bignum(cp, end, &p->p, NULL);
        if (ret < 0)
-               goto release_p;
+               goto release_u;
        cp += ret;
-       ret = read_bignum(cp, end, &u, NULL);
+       ret = read_openssh_bignum(cp, end, &p->q, NULL);
        if (ret < 0)
-               goto release_q;
+               goto release_p;
+       return bits;
+release_p:
+       gcry_mpi_release(p->p);
+release_u:
+       gcry_mpi_release(p->u);
+release_d:
+       gcry_mpi_release(p->d);
+release_e:
+       gcry_mpi_release(p->e);
+release_n:
+       gcry_mpi_release(p->n);
+       return ret;
+}
+
+static int get_private_key(const char *key_file, struct asymmetric_key **result)
+{
+       struct rsa_params params;
+       unsigned char *blob, *end;
+       unsigned bits;
+       int ret, key_type;
+       gcry_error_t gret;
+       size_t erroff, blob_size;
+       gcry_sexp_t sexp;
+       struct asymmetric_key *key;
+
+       *result = NULL;
+       ret = decode_private_key(key_file, &blob, &blob_size);
+       if (ret < 0)
+               return ret;
+       key_type = ret;
+       end = blob + blob_size;
+       if (key_type == PKT_PEM)
+               ret = find_pem_bignum_offset(blob, blob_size);
+       else
+               ret = find_openssh_bignum_offset(blob, blob_size);
+       if (ret < 0)
+               goto free_blob;
+       PARA_INFO_LOG("reading RSA params at offset %d\n", ret);
+       if (key_type == PKT_PEM)
+               ret = read_pem_rsa_params(blob + ret, end, &params);
+       else
+               ret = read_openssh_rsa_params(blob + ret, end, &params);
+       if (ret < 0)
+               goto free_blob;
+       bits = ret;
        /*
         * OpenSSL uses slightly different parameters than gcrypt. To use these
         * parameters we need to swap the values of p and q and recompute u.
         */
-       if (gcry_mpi_cmp(pq) > 0) {
-               gcry_mpi_swap(pq);
-               gcry_mpi_invm(u, p, q);
+       if (gcry_mpi_cmp(params.p, params.q) > 0) {
+               gcry_mpi_swap(params.p, params.q);
+               gcry_mpi_invm(params.u, params.p, params.q);
        }
-       gret = gcry_sexp_build(&sexp, &erroff, RSA_PRIVKEY_SEXP,
-               n, e, d, p, q, u);
+       gret = gcry_sexp_build(&sexp, &erroff, RSA_PRIVKEY_SEXP, params.n,
+               params.e, params.d, params.p, params.q, params.u);
 
        if (gret) {
                PARA_ERROR_LOG("offset %zu: %s\n", erroff,
                        gcry_strerror(gcry_err_code(gret)));
                ret = -E_SEXP_BUILD;
-               goto release_u;
+               goto free_params;
        }
        key = para_malloc(sizeof(*key));
        key->sexp = sexp;
        *result = key;
        ret = bits;
        PARA_INFO_LOG("succesfully read %d bit private key\n", ret);
-release_u:
-       gcry_mpi_release(u);
-release_q:
-       gcry_mpi_release(q);
-release_p:
-       gcry_mpi_release(p);
-release_d:
-       gcry_mpi_release(d);
-release_e:
-       gcry_mpi_release(e);
-release_n:
-       gcry_mpi_release(n);
+free_params:
+       gcry_mpi_release(params.n);
+       gcry_mpi_release(params.e);
+       gcry_mpi_release(params.d);
+       gcry_mpi_release(params.u);
+       gcry_mpi_release(params.p);
+       gcry_mpi_release(params.q);
+
 free_blob:
        free(blob);
        return ret;
@@ -382,34 +413,25 @@ int apc_get_pubkey(const char *key_file, struct asymmetric_key **result)
        unsigned char *blob, *p, *end;
        int ret;
        gcry_error_t gret;
-       size_t nr_scanned, erroff, decoded_size;
+       size_t erroff, decoded_size;
        gcry_mpi_t e, n;
        gcry_sexp_t sexp;
        struct asymmetric_key *key;
+       unsigned bits;
 
-       ret = decode_ssh_key(key_file, &blob, &decoded_size);
+       ret = decode_public_key(key_file, &blob, &decoded_size);
        if (ret < 0)
                return ret;
        p = blob + ret;
        end = blob + decoded_size;
        PARA_DEBUG_LOG("scanning modulus and public exponent\n");
-       gret = gcry_mpi_scan(&e, GCRYMPI_FMT_SSH, p, end - p, &nr_scanned);
-       if (gret) {
-               ret = -E_MPI_SCAN;
-               PARA_CRIT_LOG("%s\n", gcry_strerror(gcry_err_code(gret)));
+       ret = read_openssh_bignum(p, end, &e, NULL);
+       if (ret < 0)
                goto free_blob;
-       }
-       PARA_DEBUG_LOG("scanned e (%zu bytes)\n", nr_scanned);
-       p += nr_scanned;
-       if (p >= end)
-               goto release_e;
-       gret = gcry_mpi_scan(&n, GCRYMPI_FMT_SSH, p, end - p, &nr_scanned);
-       if (gret) {
-               ret = -E_MPI_SCAN;
-               PARA_ERROR_LOG("%s\n", gcry_strerror(gcry_err_code(gret)));
+       p += ret;
+       ret = read_openssh_bignum(p, end, &n, &bits);
+       if (ret < 0)
                goto release_e;
-       }
-       PARA_DEBUG_LOG("scanned n (%zu bytes)\n", nr_scanned);
        gret = gcry_sexp_build(&sexp, &erroff, RSA_PUBKEY_SEXP, n, e);
        if (gret) {
                PARA_ERROR_LOG("offset %zu: %s\n", erroff,
@@ -417,12 +439,12 @@ int apc_get_pubkey(const char *key_file, struct asymmetric_key **result)
                ret = -E_SEXP_BUILD;
                goto release_n;
        }
-       ret = ROUND_DOWN(nr_scanned, 32);
-       PARA_INFO_LOG("successfully read %d bit ssh public key\n", ret * 8);
+       PARA_INFO_LOG("successfully read %u bit ssh public key\n", bits);
        key = para_malloc(sizeof(*key));
        key->num_bytes = ret;
        key->sexp = sexp;
        *result = key;
+       ret = bits;
 release_n:
        gcry_mpi_release(n);
 release_e: