X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=gcrypt.c;h=69c2c34f0b4e87fd57b0c22f2a6d7725eaaaa043;hp=58fa507b6e1f96303998e0f6ba0ae47f90beb493;hb=74f74cde7afdba9cfe316998aba9286764bb5d34;hpb=3699a583f3a7e9514c0f47b8b07f56b050430b67

diff --git a/gcrypt.c b/gcrypt.c
index 58fa507b..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
 
@@ -106,15 +107,23 @@ 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;
 	unsigned char *blob = NULL;
@@ -124,13 +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))
@@ -151,6 +169,9 @@ static int decode_key(const char *key_file, unsigned char **result,
 	key[j] = '\0';
 	ret = base64_decode(key, j, (char **)&blob, blob_size);
 	free(key);
+	if (ret < 0)
+		goto unmap;
+	ret = key_type;
 unmap:
 	ret2 = para_munmap(map, map_size);
 	if (ret >= 0 && ret2 < 0)
@@ -208,7 +229,7 @@ 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;
@@ -267,27 +288,27 @@ static int read_pem_rsa_params(unsigned char *start, unsigned char *end,
 	unsigned bits;
 	int ret;
 
-	ret = read_bignum(cp, end, &p->n, &bits);
+	ret = read_pem_bignum(cp, end, &p->n, &bits);
 	if (ret < 0)
 		return ret;
 	cp += ret;
-	ret = read_bignum(cp, end, &p->e, NULL);
+	ret = read_pem_bignum(cp, end, &p->e, NULL);
 	if (ret < 0)
 		goto release_n;
 	cp += ret;
-	ret = read_bignum(cp, end, &p->d, NULL);
+	ret = read_pem_bignum(cp, end, &p->d, NULL);
 	if (ret < 0)
 		goto release_e;
 	cp += ret;
-	ret = read_bignum(cp, end, &p->p, NULL);
+	ret = read_pem_bignum(cp, end, &p->p, NULL);
 	if (ret < 0)
 		goto release_d;
 	cp += ret;
-	ret = read_bignum(cp, end, &p->q, NULL);
+	ret = read_pem_bignum(cp, end, &p->q, NULL);
 	if (ret < 0)
 		goto release_p;
 	cp += ret;
-	ret = read_bignum(cp, end, &p->u, NULL);
+	ret = read_pem_bignum(cp, end, &p->u, NULL);
 	if (ret < 0)
 		goto release_q;
 	return bits;
@@ -304,7 +325,7 @@ release_n:
 	return ret;
 }
 
-static int find_privkey_bignum_offset(const unsigned char *data, int len)
+static int find_pem_bignum_offset(const unsigned char *data, int len)
 {
 	const unsigned char *p = data, *end = data + len;
 
@@ -336,27 +357,98 @@ 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 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)
+		return ret;
+	cp += ret;
+	ret = read_openssh_bignum(cp, end, &p->e, NULL);
+	if (ret < 0)
+		goto release_n;
+	cp += ret;
+	ret = read_openssh_bignum(cp, end, &p->d, NULL);
+	if (ret < 0)
+		goto release_e;
+	cp += ret;
+	ret = read_openssh_bignum(cp, end, &p->u, NULL);
+	if (ret < 0)
+		goto release_d;
+	cp += ret;
+	ret = read_openssh_bignum(cp, end, &p->p, NULL);
+	if (ret < 0)
+		goto release_u;
+	cp += ret;
+	ret = read_openssh_bignum(cp, end, &p->q, NULL);
+	if (ret < 0)
+		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;
-	int ret;
 	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_key(key_file, &blob, &blob_size);
+	ret = decode_private_key(key_file, &blob, &blob_size);
 	if (ret < 0)
 		return ret;
+	key_type = ret;
 	end = blob + blob_size;
-	ret = find_privkey_bignum_offset(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);
-	ret = read_pem_rsa_params(blob + ret, end, &params);
+	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;
@@ -400,34 +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,
@@ -435,12 +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: