X-Git-Url: https://tinc-vpn.org/git/browse?a=blobdiff_plain;f=src%2Fgcrypt%2Frsa.c;h=292c7739dec556d8e90c9081b9c020371ccf3711;hb=bc4df95a48857aa4ab65fb47eabd48c48d650ca0;hp=1162ddf63aab450ddbbc25f7d7478141d9fc3e43;hpb=efca41606d4083eade90047d57cb963eb3b7e731;p=tinc

diff --git a/src/gcrypt/rsa.c b/src/gcrypt/rsa.c
index 1162ddf6..292c7739 100644
--- a/src/gcrypt/rsa.c
+++ b/src/gcrypt/rsa.c
@@ -23,6 +23,7 @@
 
 #include "pem.h"
 
+#include "asn1.h"
 #include "rsa.h"
 #include "../logger.h"
 #include "../rsa.h"
@@ -84,20 +85,11 @@ static size_t ber_read_len(unsigned char **p, size_t *buflen) {
 	}
 }
 
-
-static bool ber_read_sequence(unsigned char **p, size_t *buflen, size_t *result) {
+static bool ber_skip_sequence(unsigned char **p, size_t *buflen) {
 	int tag = ber_read_id(p, buflen);
-	size_t len = ber_read_len(p, buflen);
 
-	if(tag == 0x10) {
-		if(result) {
-			*result = len;
-		}
-
-		return true;
-	} else {
-		return false;
-	}
+	return tag == TAG_SEQUENCE &&
+	       ber_read_len(p, buflen) > 0;
 }
 
 static bool ber_read_mpi(unsigned char **p, size_t *buflen, gcry_mpi_t *mpi) {
@@ -119,8 +111,12 @@ static bool ber_read_mpi(unsigned char **p, size_t *buflen, gcry_mpi_t *mpi) {
 	return mpi ? !err : true;
 }
 
+rsa_t *rsa_new(void) {
+	return xzalloc(sizeof(rsa_t));
+}
+
 rsa_t *rsa_set_hex_public_key(const char *n, const char *e) {
-	rsa_t *rsa = xzalloc(sizeof(rsa_t));
+	rsa_t *rsa = rsa_new();
 
 	gcry_error_t err = gcry_mpi_scan(&rsa->n, GCRYMPI_FMT_HEX, n, 0, NULL);
 
@@ -130,7 +126,7 @@ rsa_t *rsa_set_hex_public_key(const char *n, const char *e) {
 
 	if(err) {
 		logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading RSA public key: %s", gcry_strerror(errno));
-		free(rsa);
+		rsa_free(rsa);
 		return false;
 	}
 
@@ -138,7 +134,7 @@ rsa_t *rsa_set_hex_public_key(const char *n, const char *e) {
 }
 
 rsa_t *rsa_set_hex_private_key(const char *n, const char *e, const char *d) {
-	rsa_t *rsa = xzalloc(sizeof(rsa_t));
+	rsa_t *rsa = rsa_new();
 
 	gcry_error_t err = gcry_mpi_scan(&rsa->n, GCRYMPI_FMT_HEX, n, 0, NULL);
 
@@ -152,8 +148,8 @@ rsa_t *rsa_set_hex_private_key(const char *n, const char *e, const char *d) {
 
 	if(err) {
 		logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading RSA public key: %s", gcry_strerror(errno));
-		free(rsa);
-		return false;
+		rsa_free(rsa);
+		return NULL;
 	}
 
 	return rsa;
@@ -170,14 +166,14 @@ rsa_t *rsa_read_pem_public_key(FILE *fp) {
 		return NULL;
 	}
 
-	rsa_t *rsa = xzalloc(sizeof(rsa_t));
+	rsa_t *rsa = rsa_new();
 
-	if(!ber_read_sequence(&derp, &derlen, NULL)
+	if(!ber_skip_sequence(&derp, &derlen)
 	                || !ber_read_mpi(&derp, &derlen, &rsa->n)
 	                || !ber_read_mpi(&derp, &derlen, &rsa->e)
 	                || derlen) {
 		logger(DEBUG_ALWAYS, LOG_ERR, "Error while decoding RSA public key");
-		free(rsa);
+		rsa_free(rsa);
 		return NULL;
 	}
 
@@ -193,9 +189,9 @@ rsa_t *rsa_read_pem_private_key(FILE *fp) {
 		return NULL;
 	}
 
-	rsa_t *rsa = xzalloc(sizeof(rsa_t));
+	rsa_t *rsa = rsa_new();
 
-	if(!ber_read_sequence(&derp, &derlen, NULL)
+	if(!ber_skip_sequence(&derp, &derlen)
 	                || !ber_read_mpi(&derp, &derlen, NULL)
 	                || !ber_read_mpi(&derp, &derlen, &rsa->n)
 	                || !ber_read_mpi(&derp, &derlen, &rsa->e)
@@ -207,10 +203,11 @@ rsa_t *rsa_read_pem_private_key(FILE *fp) {
 	                || !ber_read_mpi(&derp, &derlen, NULL) // u
 	                || derlen) {
 		logger(DEBUG_ALWAYS, LOG_ERR, "Error while decoding RSA private key");
-		free(rsa);
-		return NULL;
+		rsa_free(rsa);
+		rsa = NULL;
 	}
 
+	memzero(derbuf, sizeof(derbuf));
 	return rsa;
 }
 
@@ -218,19 +215,27 @@ size_t rsa_size(const rsa_t *rsa) {
 	return (gcry_mpi_get_nbits(rsa->n) + 7) / 8;
 }
 
+static bool check(gcry_error_t err) {
+	if(err) {
+		logger(DEBUG_ALWAYS, LOG_ERR, "gcrypt error %s/%s", gcry_strsource(err), gcry_strerror(err));
+	}
+
+	return !err;
+}
+
 /* Well, libgcrypt has functions to handle RSA keys, but they suck.
  * So we just use libgcrypt's mpi functions, and do the math ourselves.
  */
 
-// TODO: get rid of this macro, properly clean up gcry_ structures after use
-#define check(foo) { gcry_error_t err = (foo); if(err) {logger(DEBUG_ALWAYS, LOG_ERR, "gcrypt error %s/%s at %s:%d", gcry_strsource(err), gcry_strerror(err), __FILE__, __LINE__); return false; }}
+static bool rsa_powm(const gcry_mpi_t ed, const gcry_mpi_t n, const void *in, size_t len, void *out) {
+	gcry_mpi_t inmpi = NULL;
 
-bool rsa_public_encrypt(rsa_t *rsa, const void *in, size_t len, void *out) {
-	gcry_mpi_t inmpi;
-	check(gcry_mpi_scan(&inmpi, GCRYMPI_FMT_USG, in, len, NULL));
+	if(!check(gcry_mpi_scan(&inmpi, GCRYMPI_FMT_USG, in, len, NULL))) {
+		return false;
+	}
 
-	gcry_mpi_t outmpi = gcry_mpi_new(len * 8);
-	gcry_mpi_powm(outmpi, inmpi, rsa->e, rsa->n);
+	gcry_mpi_t outmpi = gcry_mpi_snew(len * 8);
+	gcry_mpi_powm(outmpi, inmpi, ed, n);
 
 	size_t out_bytes = (gcry_mpi_get_nbits(outmpi) + 7) / 8;
 	size_t pad = len - MIN(out_bytes, len);
@@ -240,28 +245,20 @@ bool rsa_public_encrypt(rsa_t *rsa, const void *in, size_t len, void *out) {
 		*pout++ = 0;
 	}
 
-	check(gcry_mpi_print(GCRYMPI_FMT_USG, pout, len, NULL, outmpi));
-
-	return true;
-}
-
-bool rsa_private_decrypt(rsa_t *rsa, const void *in, size_t len, void *out) {
-	gcry_mpi_t inmpi;
-	check(gcry_mpi_scan(&inmpi, GCRYMPI_FMT_USG, in, len, NULL));
-
-	gcry_mpi_t outmpi = gcry_mpi_new(len * 8);
-	gcry_mpi_powm(outmpi, inmpi, rsa->d, rsa->n);
+	bool ok = check(gcry_mpi_print(GCRYMPI_FMT_USG, pout, len, NULL, outmpi));
 
-	size_t pad = len - (gcry_mpi_get_nbits(outmpi) + 7) / 8;
-	unsigned char *pout = out;
+	gcry_mpi_release(outmpi);
+	gcry_mpi_release(inmpi);
 
-	for(; pad; --pad) {
-		*pout++ = 0;
-	}
+	return ok;
+}
 
-	check(gcry_mpi_print(GCRYMPI_FMT_USG, pout, len, NULL, outmpi));
+bool rsa_public_encrypt(rsa_t *rsa, const void *in, size_t len, void *out) {
+	return rsa_powm(rsa->e, rsa->n, in, len, out);
+}
 
-	return true;
+bool rsa_private_decrypt(rsa_t *rsa, const void *in, size_t len, void *out) {
+	return rsa_powm(rsa->d, rsa->n, in, len, out);
 }
 
 void rsa_free(rsa_t *rsa) {