X-Git-Url: http://git.tuebingen.mpg.de/?a=blobdiff_plain;f=gcrypt.c;h=5d151a3cc9f7c42e6322f1748902b14281b49f1c;hb=3f6b7dd0ed39f7008ec09def9239f379b87cd7c1;hp=abc3272a6490ca541f1385c992c6ee99d5ef7986;hpb=71386e2530fa351d22f942ce3cf9d18eee99ce78;p=paraslash.git

diff --git a/gcrypt.c b/gcrypt.c
index abc3272a..5d151a3c 100644
--- a/gcrypt.c
+++ b/gcrypt.c
@@ -256,6 +256,54 @@ static int read_bignum(unsigned char *start, unsigned char *end, gcry_mpi_t *bn,
 	return cp - start;
 }
 
+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_bignum(cp, end, &p->n, &bits);
+	if (ret < 0)
+		return ret;
+	cp += ret;
+	ret = read_bignum(cp, end, &p->e, NULL);
+	if (ret < 0)
+		goto release_n;
+	cp += ret;
+	ret = read_bignum(cp, end, &p->d, NULL);
+	if (ret < 0)
+		goto release_e;
+	cp += ret;
+	ret = read_bignum(cp, end, &p->p, NULL);
+	if (ret < 0)
+		goto release_d;
+	cp += ret;
+	ret = read_bignum(cp, end, &p->q, NULL);
+	if (ret < 0)
+		goto release_p;
+	cp += ret;
+	ret = read_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_privkey_bignum_offset(const unsigned char *data, int len)
 {
 	const unsigned char *p = data, *end = data + len;
@@ -288,11 +336,30 @@ static int find_privkey_bignum_offset(const unsigned char *data, int len)
 	return p - data;
 }
 
+static int read_openssh_bignum(unsigned char *start, unsigned char *end,
+		gcry_mpi_t *bn, unsigned *bitsp)
+{
+	gcry_error_t gret;
+	size_t nscanned;
+	unsigned bits;
+
+	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;
+}
+
 static int get_private_key(const char *key_file, struct asymmetric_key **result)
 {
-	gcry_mpi_t n = NULL, e = NULL, d = NULL, p = NULL, q = NULL,
-		u = NULL;
-	unsigned char *blob, *cp, *end;
+	struct rsa_params params;
+	unsigned char *blob, *end;
 	int ret;
 	unsigned bits;
 	gcry_error_t gret;
@@ -309,69 +376,40 @@ static int get_private_key(const char *key_file, struct asymmetric_key **result)
 	if (ret < 0)
 		goto free_blob;
 	PARA_INFO_LOG("reading RSA params at offset %d\n", ret);
-	cp = blob + ret;
-
-	ret = read_bignum(cp, end, &n, &bits);
+	ret = read_pem_rsa_params(blob + ret, end, &params);
 	if (ret < 0)
 		goto free_blob;
-	cp += ret;
-
-	ret = read_bignum(cp, end, &e, NULL);
-	if (ret < 0)
-		goto release_n;
-	cp += ret;
-
-	ret = read_bignum(cp, end, &d, NULL);
-	if (ret < 0)
-		goto release_e;
-	cp += ret;
-
-	ret = read_bignum(cp, end, &p, NULL);
-	if (ret < 0)
-		goto release_d;
-	cp += ret;
-
-	ret = read_bignum(cp, end, &q, NULL);
-	if (ret < 0)
-		goto release_p;
-	cp += ret;
-	ret = read_bignum(cp, end, &u, NULL);
-	if (ret < 0)
-		goto release_q;
+	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(p, q) > 0) {
-		gcry_mpi_swap(p, q);
-		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;
@@ -382,10 +420,11 @@ 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);
 	if (ret < 0)
@@ -393,23 +432,13 @@ int apc_get_pubkey(const char *key_file, struct asymmetric_key **result)
 	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 +446,12 @@ 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: