upstream commit

avoid BIGNUM in KRL code by using a simple bitmap;
 feedback and ok markus

Makefile.in

@@ -70,7 +70,9 @@ LIBOPENSSH_OBJS=\
 	sshkey.o \
 	sshbuf-getput-basic.o \
 	sshbuf-misc.o \
-	sshbuf-getput-crypto.o
+	sshbuf-getput-crypto.o \
+	krl.o \
+	bitmap.o
 
 LIBSSH_OBJS=${LIBOPENSSH_OBJS} \
 	authfd.o authfile.o bufaux.o bufbn.o buffer.o \
@@ -83,7 +85,7 @@ LIBSSH_OBJS=${LIBOPENSSH_OBJS} \
 	monitor_fdpass.o rijndael.o ssh-dss.o ssh-ecdsa.o ssh-rsa.o dh.o \
 	kexdh.o kexgex.o kexdhc.o kexgexc.o bufec.o kexecdh.o kexecdhc.o \
 	msg.o progressmeter.o dns.o entropy.o gss-genr.o umac.o umac128.o \
-	ssh-pkcs11.o krl.o smult_curve25519_ref.o \
+	ssh-pkcs11.o smult_curve25519_ref.o \
 	kexc25519.o kexc25519c.o poly1305.o chacha.o cipher-chachapoly.o \
 	ssh-ed25519.o digest-openssl.o hmac.o \
 	sc25519.o ge25519.o fe25519.o ed25519.o verify.o hash.o blocks.o

krl.c

@@ -14,7 +14,7 @@
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $OpenBSD: krl.c,v 1.25 2015/01/13 19:04:35 djm Exp $ */
+/* $OpenBSD: krl.c,v 1.26 2015/01/14 15:02:39 djm Exp $ */
 
 #include "includes.h"
 
@@ -37,6 +37,7 @@
 #include "misc.h"
 #include "log.h"
 #include "digest.h"
+#include "bitmap.h"
 
 #include "krl.h"
 
@@ -519,6 +520,25 @@ choose_next_state(int current_state, u_int64_t contig, int final,
 	return new_state;
 }
 
+static int
+put_bitmap(struct sshbuf *buf, struct bitmap *bitmap)
+{
+	size_t len;
+	u_char *blob;
+	int r;
+
+	len = bitmap_nbytes(bitmap);
+	if ((blob = malloc(len)) == NULL)
+		return SSH_ERR_ALLOC_FAIL;
+	if (bitmap_to_string(bitmap, blob, len) != 0) {
+		free(blob);
+		return SSH_ERR_INTERNAL_ERROR;
+	}
+	r = sshbuf_put_bignum2_bytes(buf, blob, len);
+	free(blob);
+	return r;
+}
+
 /* Generate a KRL_SECTION_CERTIFICATES KRL section */
 static int
 revoked_certs_generate(struct revoked_certs *rc, struct sshbuf *buf)
@@ -529,7 +549,7 @@ revoked_certs_generate(struct revoked_certs *rc, struct sshbuf *buf)
 	struct revoked_key_id *rki;
 	int next_state, state = 0;
 	struct sshbuf *sect;
-	BIGNUM *bitmap = NULL;
+	struct bitmap *bitmap = NULL;
 
 	if ((sect = sshbuf_new()) == NULL)
 		return SSH_ERR_ALLOC_FAIL;
@@ -572,9 +592,9 @@ revoked_certs_generate(struct revoked_certs *rc, struct sshbuf *buf)
 			case KRL_SECTION_CERT_SERIAL_RANGE:
 				break;
 			case KRL_SECTION_CERT_SERIAL_BITMAP:
-				if ((r = sshbuf_put_bignum2(sect, bitmap)) != 0)
+				if ((r = put_bitmap(sect, bitmap)) != 0)
 					goto out;
-				BN_free(bitmap);
+				bitmap_free(bitmap);
 				bitmap = NULL;
 				break;
 			}
@@ -595,7 +615,7 @@ revoked_certs_generate(struct revoked_certs *rc, struct sshbuf *buf)
 			case KRL_SECTION_CERT_SERIAL_RANGE:
 				break;
 			case KRL_SECTION_CERT_SERIAL_BITMAP:
-				if ((bitmap = BN_new()) == NULL) {
+				if ((bitmap = bitmap_new()) == NULL) {
 					r = SSH_ERR_ALLOC_FAIL;
 					goto out;
 				}
@@ -626,8 +646,8 @@ revoked_certs_generate(struct revoked_certs *rc, struct sshbuf *buf)
 				goto out;
 			}
 			for (i = 0; i < contig; i++) {
-				if (BN_set_bit(bitmap,
+				if (bitmap_set_bit(bitmap,
-				    rs->lo + i - bitmap_start) != 1) {
+				    rs->lo + i - bitmap_start) != 0) {
 					r = SSH_ERR_ALLOC_FAIL;
 					goto out;
 				}
@@ -645,9 +665,9 @@ revoked_certs_generate(struct revoked_certs *rc, struct sshbuf *buf)
 		case KRL_SECTION_CERT_SERIAL_RANGE:
 			break;
 		case KRL_SECTION_CERT_SERIAL_BITMAP:
-			if ((r = sshbuf_put_bignum2(sect, bitmap)) != 0)
+			if ((r = put_bitmap(sect, bitmap)) != 0)
 				goto out;
-			BN_free(bitmap);
+			bitmap_free(bitmap);
 			bitmap = NULL;
 			break;
 		}
@@ -671,8 +691,7 @@ revoked_certs_generate(struct revoked_certs *rc, struct sshbuf *buf)
 	}
 	r = 0;
  out:
-	if (bitmap != NULL)
+	bitmap_free(bitmap);
-		BN_free(bitmap);
 	sshbuf_free(sect);
 	return r;
 }
@@ -784,13 +803,13 @@ format_timestamp(u_int64_t timestamp, char *ts, size_t nts)
 static int
 parse_revoked_certs(struct sshbuf *buf, struct ssh_krl *krl)
 {
-	int r = SSH_ERR_INTERNAL_ERROR, nbits;
+	int r = SSH_ERR_INTERNAL_ERROR;
 	u_char type;
 	const u_char *blob;
-	size_t blen;
+	size_t blen, nbits;
 	struct sshbuf *subsect = NULL;
 	u_int64_t serial, serial_lo, serial_hi;
-	BIGNUM *bitmap = NULL;
+	struct bitmap *bitmap = NULL;
 	char *key_id = NULL;
 	struct sshkey *ca_key = NULL;
 
@@ -834,31 +853,32 @@ parse_revoked_certs(struct sshbuf *buf, struct ssh_krl *krl)
 				goto out;
 			break;
 		case KRL_SECTION_CERT_SERIAL_BITMAP:
-			if ((bitmap = BN_new()) == NULL) {
+			if ((bitmap = bitmap_new()) == NULL) {
 				r = SSH_ERR_ALLOC_FAIL;
 				goto out;
 			}
 			if ((r = sshbuf_get_u64(subsect, &serial_lo)) != 0 ||
-			    (r = sshbuf_get_bignum2(subsect, bitmap)) != 0)
+			    (r = sshbuf_get_bignum2_bytes_direct(subsect,
+			    &blob, &blen)) != 0)
 				goto out;
-			if ((nbits = BN_num_bits(bitmap)) < 0) {
+			if (bitmap_from_string(bitmap, blob, blen) != 0) {
-				error("%s: bitmap bits < 0", __func__);
 				r = SSH_ERR_INVALID_FORMAT;
 				goto out;
 			}
+			nbits = bitmap_nbits(bitmap);
 			for (serial = 0; serial < (u_int64_t)nbits; serial++) {
 				if (serial > 0 && serial_lo + serial == 0) {
 					error("%s: bitmap wraps u64", __func__);
 					r = SSH_ERR_INVALID_FORMAT;
 					goto out;
 				}
-				if (!BN_is_bit_set(bitmap, serial))
+				if (!bitmap_test_bit(bitmap, serial))
 					continue;
 				if ((r = ssh_krl_revoke_cert_by_serial(krl,
 				    ca_key, serial_lo + serial)) != 0)
 					goto out;
 			}
-			BN_free(bitmap);
+			bitmap_free(bitmap);
 			bitmap = NULL;
 			break;
 		case KRL_SECTION_CERT_KEY_ID:
@@ -888,7 +908,7 @@ parse_revoked_certs(struct sshbuf *buf, struct ssh_krl *krl)
 	r = 0;
  out:
 	if (bitmap != NULL)
-		BN_free(bitmap);
+		bitmap_free(bitmap);
 	free(key_id);
 	sshkey_free(ca_key);
 	sshbuf_free(subsect);

sshbuf-getput-basic.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: sshbuf-getput-basic.c,v 1.3 2015/01/12 15:18:07 djm Exp $	*/
+/*	$OpenBSD: sshbuf-getput-basic.c,v 1.4 2015/01/14 15:02:39 djm Exp $	*/
 /*
  * Copyright (c) 2011 Damien Miller
  *
@@ -424,3 +424,39 @@ sshbuf_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len)
 		memcpy(d + 4 + prepend, s, len);
 	return 0;
 }
+
+int
+sshbuf_get_bignum2_bytes_direct(struct sshbuf *buf,
+    const u_char **valp, size_t *lenp)
+{
+	const u_char *d;
+	size_t len, olen;
+	int r;
+
+	if ((r = sshbuf_peek_string_direct(buf, &d, &olen)) < 0)
+		return r;
+	len = olen;
+	/* Refuse negative (MSB set) bignums */
+	if ((len != 0 && (*d & 0x80) != 0))
+		return SSH_ERR_BIGNUM_IS_NEGATIVE;
+	/* Refuse overlong bignums, allow prepended \0 to avoid MSB set */
+	if (len > SSHBUF_MAX_BIGNUM + 1 ||
+	    (len == SSHBUF_MAX_BIGNUM + 1 && *d != 0))
+		return SSH_ERR_BIGNUM_TOO_LARGE;
+	/* Trim leading zeros */
+	while (len > 0 && *d == 0x00) {
+		d++;
+		len--;
+	}
+	if (valp != 0)
+		*valp = d;
+	if (lenp != NULL)
+		*lenp = len;
+	if (sshbuf_consume(buf, olen + 4) != 0) {
+		/* Shouldn't happen */
+		SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
+		SSHBUF_ABORT();
+		return SSH_ERR_INTERNAL_ERROR;
+	}
+	return 0;
+}

sshbuf-getput-crypto.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: sshbuf-getput-crypto.c,v 1.3 2015/01/12 15:18:07 djm Exp $	*/
+/*	$OpenBSD: sshbuf-getput-crypto.c,v 1.4 2015/01/14 15:02:39 djm Exp $	*/
 /*
  * Copyright (c) 2011 Damien Miller
  *
@@ -38,24 +38,10 @@ sshbuf_get_bignum2(struct sshbuf *buf, BIGNUM *v)
 	size_t len;
 	int r;
 
-	if ((r = sshbuf_peek_string_direct(buf, &d, &len)) < 0)
+	if ((r = sshbuf_get_bignum2_bytes_direct(buf, &d, &len)) != 0)
 		return r;
-	/* Refuse negative (MSB set) bignums */
-	if ((len != 0 && (*d & 0x80) != 0))
-		return SSH_ERR_BIGNUM_IS_NEGATIVE;
-	/* Refuse overlong bignums, allow prepended \0 to avoid MSB set */
-	if (len > SSHBUF_MAX_BIGNUM + 1 ||
-	    (len == SSHBUF_MAX_BIGNUM + 1 && *d != 0))
-		return SSH_ERR_BIGNUM_TOO_LARGE;
 	if (v != NULL && BN_bin2bn(d, len, v) == NULL)
 		return SSH_ERR_ALLOC_FAIL;
-	/* Consume the string */
-	if (sshbuf_get_string_direct(buf, NULL, NULL) != 0) {
-		/* Shouldn't happen */
-		SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
-		SSHBUF_ABORT();
-		return SSH_ERR_INTERNAL_ERROR;
-	}
 	return 0;
 }
 

sshbuf.h

@@ -1,4 +1,4 @@
-/*	$OpenBSD: sshbuf.h,v 1.3 2014/06/24 01:13:21 djm Exp $	*/
+/*	$OpenBSD: sshbuf.h,v 1.4 2015/01/14 15:02:39 djm Exp $	*/
 /*
  * Copyright (c) 2011 Damien Miller
  *
@@ -212,6 +212,8 @@ int	sshbuf_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len);
 #ifdef WITH_OPENSSL
 int	sshbuf_get_bignum2(struct sshbuf *buf, BIGNUM *v);
 int	sshbuf_get_bignum1(struct sshbuf *buf, BIGNUM *v);
+int	sshbuf_get_bignum2_bytes_direct(struct sshbuf *buf,
+	    const u_char **valp, size_t *lenp);
 int	sshbuf_put_bignum2(struct sshbuf *buf, const BIGNUM *v);
 int	sshbuf_put_bignum1(struct sshbuf *buf, const BIGNUM *v);
 # ifdef OPENSSL_HAS_ECC