add a new function

void sc_mem_clear(void *ptr, size_t len);
to clear a memory buffer. If OpenSSL is used this function
is a wrapper for OPENSSL_cleanse, otherwise memset is currenlty used.

Use this function to clear memory buffers with sensitive content.


git-svn-id: https://www.opensc-project.org/svnp/opensc/trunk@2601 c6295689-39f2-0310-b995-f0e70906c6a9

src/libopensc/card-gpk.c

@@ -159,10 +159,9 @@ gpk_init(sc_card_t *card)
 	unsigned long	exponent, flags, kg;
 	unsigned char info[13];
 
-	card->drv_data = priv = (struct gpk_private_data *) malloc(sizeof(*priv));
+	card->drv_data = priv = (struct gpk_private_data *) calloc(1, sizeof(*priv));
 	if (card->drv_data == NULL)
 		return SC_ERROR_OUT_OF_MEMORY;
-	memset(priv, 0, sizeof(*priv));
 
 	/* read/write/update binary expect offset to be the
 	 * number of 32 bit words.
@@ -816,9 +815,9 @@ gpk_compute_crycks(sc_card_t *card, sc_apdu_t *apdu,
 		memcpy(crycks1, out, 3);
 	des_cleanse(k1);
 	des_cleanse(k2);
-	memset(in, 0, sizeof(in));
+	sc_mem_clear(in, sizeof(in));
-	memset(out, 0, sizeof(out));
+	sc_mem_clear(out, sizeof(out));
-	memset(block, 0, sizeof(block));
+	sc_mem_clear(block, sizeof(block));
 	return 0;
 }
 
@@ -959,7 +958,7 @@ gpk_set_filekey(const u8 *key, const u8 *challenge,
 
 	des_cleanse(k1);
 	des_cleanse(k2);
-	memset(out, 0, sizeof(out));
+	sc_mem_clear(out, sizeof(out));
 	return r;
 }
 
@@ -1008,7 +1007,7 @@ gpk_select_key(sc_card_t *card, int key_sfi, const u8 *buf, size_t buflen)
 		priv->key_reference = key_sfi;
 	}
 
-	memset(resp, 0, sizeof(resp));
+	sc_mem_clear(resp, sizeof(resp));
 	return r;
 }
 

src/libopensc/card-oberthur.c

@@ -1712,7 +1712,7 @@ auth_update_component(sc_card_t *card, struct sc_cardctl_oberthur_updatekey_info
 	}
 
 	rv = sc_transmit_apdu(card, &apdu);
-	memset(sbuf, 0, sizeof(sbuf));
+	sc_mem_clear(sbuf, sizeof(sbuf));
 	SC_TEST_RET(card->ctx, rv, "APDU transmit failed");
 
 	rv = sc_check_sw(card, apdu.sw1, apdu.sw2);
@@ -1937,7 +1937,7 @@ auth_verify(sc_card_t *card, unsigned int type,
 	apdu.lc = pinfo.pad_length;
 	apdu.sensitive = 1;
 	rv = sc_transmit_apdu(card, &apdu);
-	memset(sbuf, 0, sizeof(sbuf));
+	sc_mem_clear(sbuf, sizeof(sbuf));
 	SC_TEST_RET(card->ctx, rv, "APDU transmit failed");
 
 	if (tries_left && apdu.sw1 == 0x63 && (apdu.sw2 & 0xF0) == 0xC0) 
@@ -1979,7 +1979,7 @@ auth_change_reference_data (sc_card_t *card, unsigned int type,
 	apdu.sensitive = 1;
 
 	rv = sc_transmit_apdu(card, &apdu);
-	memset(sbuf, 0, sizeof(sbuf));
+	sc_mem_clear(sbuf, sizeof(sbuf));
 	SC_TEST_RET(card->ctx, rv, "APDU transmit failed");
 
 	if (tries_left && apdu.sw1 == 0x63 && (apdu.sw2 & 0xF0) == 0xC0) 
@@ -2030,7 +2030,7 @@ auth_reset_retry_counter(sc_card_t *card, unsigned int type,
 	apdu.sensitive = 1;
 
 	rv = sc_transmit_apdu(card, &apdu);
-	memset(sbuf, 0, sizeof(sbuf));
+	sc_mem_clear(sbuf, sizeof(sbuf));
 	SC_TEST_RET(card->ctx, rv, "APDU transmit failed");
 
 	rv = sc_check_sw(card, apdu.sw1, apdu.sw2);
@@ -2093,7 +2093,7 @@ auth_create_reference_data (sc_card_t *card,
 	apdu.sensitive = 1;
 
 	rv = sc_transmit_apdu(card, &apdu);
-	memset(sbuf, 0, sizeof(sbuf));
+	sc_mem_clear(sbuf, sizeof(sbuf));
 	SC_TEST_RET(card->ctx, rv, "APDU transmit failed");
 	
 	rv = sc_check_sw(card, apdu.sw1, apdu.sw2);

src/libopensc/card.c

@@ -223,7 +223,7 @@ static int sc_transceive(sc_card_t *card, sc_apdu_t *apdu)
 					sendsize, rbuf, &recvsize,
 					apdu->control);
 	if (apdu->sensitive)
-		memset(sbuf, 0, sendsize);
+		sc_mem_clear(sbuf, sendsize);
 	SC_TEST_RET(card->ctx, r, "Unable to transmit");
 
 	assert(recvsize >= 2);
@@ -239,7 +239,7 @@ static int sc_transceive(sc_card_t *card, sc_apdu_t *apdu)
 	if (recvsize > 0) {
 		memcpy(apdu->resp, rbuf, data_bytes);
 		if (apdu->sensitive)
-			memset(rbuf, 0, recvsize);
+			sc_mem_clear(rbuf, recvsize);
 	}
 	return 0;
 }
@@ -354,7 +354,7 @@ static void sc_card_free(sc_card_t *card)
 	if (card->algorithms != NULL)
 		free(card->algorithms);
 	sc_mutex_free(card->mutex);
-	memset(card, 0, sizeof(*card));
+	sc_mem_clear(card, sizeof(*card));
 	free(card);
 }
 

src/libopensc/ctx.c

@@ -740,7 +740,7 @@ int sc_release_context(sc_context_t *ctx)
 		scconf_free(ctx->conf);
 	sc_mutex_free(ctx->mutex);
 	free(ctx->app_name);
-	memset(ctx, 0, sizeof(*ctx));
+	sc_mem_clear(ctx, sizeof(*ctx));
 	free(ctx);
 	return SC_SUCCESS;
 }

src/libopensc/iso7816.c

@@ -896,7 +896,7 @@ static int iso7816_pin_cmd(sc_card_t *card, struct sc_pin_cmd_data *data,
 		r = sc_transmit_apdu(card, apdu);
 
 		/* Clear the buffer - it may contain pins */
-		memset(sbuf, 0, sizeof(sbuf));
+		sc_mem_clear(sbuf, sizeof(sbuf));
 	} else {
 		/* Call the reader driver to collect
 		 * the PIN and pass on the APDU to the card */

src/libopensc/opensc.h

@@ -890,6 +890,14 @@ int sc_hex_to_bin(const char *in, u8 *out, size_t *outlen);
 int sc_bin_to_hex(const u8 *, size_t, char *, size_t, int separator);
 int sc_compare_oid(const struct sc_object_id *oid1, const struct sc_object_id *oid2);
 
+/**
+ * Clears a memory buffer (note: when OpenSSL is used this is
+ * currently a wrapper for OPENSSL_cleanse() ).
+ * @param  ptr  pointer to the memory buffer
+ * @param  len  length of the memory buffer
+ */
+void sc_mem_clear(void *ptr, size_t len);
+
 int sc_get_cache_dir(sc_context_t *ctx, char *buf, size_t bufsize);
 int sc_make_cache_dir(sc_context_t *ctx);
 

src/libopensc/pkcs15-prkey.c

@@ -402,7 +402,7 @@ sc_pkcs15_erase_prkey(struct sc_pkcs15_prkey *key)
 		free(key->u.dsa.priv.data);
 		break;
 	}
-	memset(key, 0, sizeof(key));
+	sc_mem_clear(key, sizeof(key));
 }
 
 void

src/libopensc/pkcs15-pubkey.c

@@ -433,7 +433,7 @@ void sc_pkcs15_erase_pubkey(struct sc_pkcs15_pubkey *key)
 		break;
 	}
 	free(key->data.value);
-	memset(key, 0, sizeof(*key));
+	sc_mem_clear(key, sizeof(*key));
 }
 
 void sc_pkcs15_free_pubkey(struct sc_pkcs15_pubkey *key)

src/libopensc/pkcs15-sec.c

@@ -326,7 +326,7 @@ int sc_pkcs15_compute_signature(struct sc_pkcs15_card *p15card,
 		tmpin = tmpout;
 	}
 	r = sc_compute_signature(p15card->card, tmpin, inlen, out, outlen);
-	memset(buf, 0, sizeof(buf));
+	sc_mem_clear(buf, sizeof(buf));
 	sc_unlock(p15card->card);
 	SC_TEST_RET(ctx, r, "sc_compute_signature() failed");
 

src/libopensc/reader-openct.c

@@ -173,7 +173,7 @@ openct_reader_release(sc_reader_t *reader)
 	if (data) {
 		if (data->h)
 			ct_reader_disconnect(data->h);
-		memset(data, 0, sizeof(*data));
+		sc_mem_clear(data, sizeof(*data));
 		reader->drv_data = NULL;
 		free(data);
 	}

src/libopensc/sc.c

@@ -18,6 +18,10 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
 #include "internal.h"
 #include "asn1.h"
 #include <stdio.h>
@@ -25,6 +29,10 @@
 #include <string.h>
 #include <assert.h>
 
+#ifdef HAVE_OPENSSL
+#include <openssl/crypto.h>	/* for OPENSSL_cleanse */
+#endif
+
 #ifdef VERSION
 const char *sc_version = VERSION;
 #else
@@ -580,3 +588,12 @@ int _sc_parse_atr(sc_context_t *ctx, sc_slot_info_t *slot)
 	slot->atr_info.hist_bytes = p;
 	return 0;
 }
+
+void sc_mem_clear(void *ptr, size_t len)
+{
+#ifdef HAVE_OPENSSL
+	OPENSSL_cleanse(ptr, len);
+#else
+	memset(ptr, 0, len);
+#endif
+}

src/libopensc/ui.c

@@ -323,14 +323,14 @@ __sc_ui_read_pin(sc_context_t *ctx, const char *prompt,
 		}
 
 		*out = strdup(pin);
-		memset(pin, 0, len);
+		sc_mem_clear(pin, len);
 
 		if (!(flags & SC_UI_PIN_RETYPE))
 			break;
 
 		pin = getpass("Please type again to verify: ");
 		if (!strcmp(*out, pin)) {
-			memset(pin, 0, len);
+			sc_mem_clear(pin, len);
 			break;
 		}
 
@@ -345,7 +345,7 @@ __sc_ui_read_pin(sc_context_t *ctx, const char *prompt,
 		fprintf(stderr,
 			"Sorry, the two pins did not match. "
 			"Please try again.\n");
-		memset(pin, 0, strlen(pin));
+		sc_mem_clear(pin, strlen(pin));
 
 		/* Currently, there's no way out of this dialog.
 		 * We should allow the user to bail out after n

src/pkcs11/framework-pkcs15.c

@@ -248,7 +248,7 @@ __pkcs15_release_object(struct pkcs15_any_object *obj)
 	if (--(obj->refcount) != 0)
 		return obj->refcount;
 	
-	memset(obj, 0xAA, obj->size);
+	sc_mem_clear(obj, obj->size);
 	free(obj);
 
 	return 0;

src/pkcs15init/keycache.c

@@ -333,7 +333,7 @@ sc_keycache_forget_key(const sc_path_t *path, int type, int ref)
 			*prev = s->next;
 			if (s->named_pin != -1 && s->ref == -1)
 				named_pin[s->named_pin] = NULL;
-			memset(s, 0, sizeof(*s));
+			sc_mem_clear(s, sizeof(*s));
 			free(s);
 		} else {
 			prev = &s->next;