X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=gcrypt.c;h=69c2c34f0b4e87fd57b0c22f2a6d7725eaaaa043;hp=50ddff46df79820c9af24c7a4f96c02ef05f9675;hb=0b8b2469b5d2b81ff928bddd10d4ac3b819b75f8;hpb=eb833d819057adb3916aa2f2704ca2df7fd6a48f

diff --git a/gcrypt.c b/gcrypt.c
index 50ddff46..69c2c34f 100644
--- a/gcrypt.c
+++ b/gcrypt.c
@@ -12,6 +12,7 @@
 #include "crypt_backend.h"
 #include "fd.h"
 #include "base64.h"
+#include "portable_io.h"
 
 //#define GCRYPT_DEBUG 1
 
@@ -106,16 +107,25 @@ 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)
+/** Private PEM keys (legacy format) start with this header. */
+#define PRIVATE_PEM_KEY_HEADER "-----BEGIN RSA PRIVATE KEY-----"
+/** Private OPENSSH keys (RFC4716) start with this header. */
+#define PRIVATE_OPENSSH_KEY_HEADER "-----BEGIN OPENSSH PRIVATE KEY-----"
+/** Private PEM keys (legacy format) end with this footer. */
+#define PRIVATE_PEM_KEY_FOOTER "-----END RSA PRIVATE KEY-----"
+/** Private OPENSSH keys (RFC4716) end with this footer. */
+#define PRIVATE_OPENSSH_KEY_FOOTER "-----END OPENSSH PRIVATE KEY-----"
+/** Legacy PEM keys (openssh-7.7 and earlier, paraslash.0.6.2 and earlier) */
+#define PKT_PEM (0)
+/** OPENSSH keys (since openssh-7.8, paraslash.0.6.3) */
+#define PKT_OPENSSH (1)
+
+static int decode_private_key(const char *key_file, unsigned char **result,
+		size_t *blob_size)
 {
-	int ret, ret2, i, j;
+	int ret, ret2, i, j, key_type;
 	void *map;
-	size_t map_size, key_size, blob_size;
+	size_t map_size, key_size;
 	unsigned char *blob = NULL;
 	char *begin, *footer, *key;
 
@@ -123,13 +133,22 @@ static int decode_key(const char *key_file, unsigned char **result)
 	if (ret < 0)
 		goto out;
 	ret = -E_KEY_MARKER;
-	if (strncmp(map, PRIVATE_KEY_HEADER, strlen(PRIVATE_KEY_HEADER)))
+	if (strncmp(map, PRIVATE_PEM_KEY_HEADER,
+			strlen(PRIVATE_PEM_KEY_HEADER)) == 0) {
+		key_type = PKT_PEM;
+		begin = map + strlen(PRIVATE_PEM_KEY_HEADER);
+		footer = strstr(map, PRIVATE_PEM_KEY_FOOTER);
+		PARA_INFO_LOG("detected legacy PEM key %s\n", key_file);
+	} else if (strncmp(map, PRIVATE_OPENSSH_KEY_HEADER,
+			strlen(PRIVATE_OPENSSH_KEY_HEADER)) == 0) {
+		key_type = PKT_OPENSSH;
+		begin = map + strlen(PRIVATE_OPENSSH_KEY_HEADER);
+		footer = strstr(map, PRIVATE_OPENSSH_KEY_FOOTER);
+		PARA_INFO_LOG("detected openssh key %s\n", key_file);
+	} else
 		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))
@@ -148,15 +167,11 @@ static int decode_key(const char *key_file, unsigned char **result)
 		key[j++] = begin[i];
 	}
 	key[j] = '\0';
-	ret = base64_decode(key, j, (char **)&blob, &blob_size);
+	ret = base64_decode(key, j, (char **)&blob, blob_size);
 	free(key);
 	if (ret < 0)
-		goto free_unmap;
-	ret = blob_size;
-	goto unmap;
-free_unmap:
-	free(blob);
-	blob = NULL;
+		goto unmap;
+	ret = key_type;
 unmap:
 	ret2 = para_munmap(map, map_size);
 	if (ret >= 0 && ret2 < 0)
@@ -211,11 +226,11 @@ static inline int get_long_form_num_length_bytes(unsigned char c)
 
 /*
  * Returns: Number of bytes scanned. This may differ from the value returned via
- * bn_bytes because the latter does not include the ASN.1 prefix and a leading
- * zero is not considered as an additional byte for bn_bytes.
+ * 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,
-		int *bn_bytes)
+static int read_pem_bignum(unsigned char *start, unsigned char *end, gcry_mpi_t *bn,
+		unsigned *bitsp)
 {
 	int i, bn_size;
 	gcry_error_t gret;
@@ -253,8 +268,8 @@ static int read_bignum(unsigned char *start, unsigned char *end, gcry_mpi_t *bn,
 		cp++;
 		bn_size--;
 	}
-	if (bn_bytes)
-		*bn_bytes = bn_size;
+	if (bitsp)
+		*bitsp = bn_size * 8;
 	cp += bn_size;
 //	unsigned char *buf;
 //	gcry_mpi_aprint(GCRYMPI_FMT_HEX, &buf, NULL, *bn);
@@ -262,7 +277,55 @@ 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;
 
@@ -294,90 +357,131 @@ 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 blob_size, ret, n_size;
 	gcry_error_t gret;
-	size_t erroff;
-	gcry_sexp_t sexp;
-	struct asymmetric_key *key;
+	size_t nscanned;
+	unsigned bits;
 
-	*result = NULL;
-	ret = decode_key(key_file, &blob);
-	if (ret < 0)
-		return ret;
-	blob_size = 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;
+}
+
+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_bignum(cp, end, &n, &n_size);
+	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(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 = n_size * 8;
+	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;
@@ -388,34 +492,25 @@ 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,
@@ -423,12 +518,12 @@ 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: