[pkg-opensc-commit] [libp11] 62/239: add an example for decryption. however it doesn't work, will ask nils for advice how to get the openssl part right.

[Eric Dorland]

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commit 8dd2bca092fe92a2b8198265b0999ddc94fc987f
Author: Andreas Jellinghaus <andreas at ionisiert.de>
Date:   Thu Oct 20 14:11:53 2005 +0000

    add an example for decryption. however it doesn't work,
    will ask nils for advice how to get the openssl part
    right.
---
 examples/Makefile  |   4 +-
 examples/decrypt.c | 227 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 229 insertions(+), 2 deletions(-)

diff --git a/examples/Makefile b/examples/Makefile
index 8f1d4c6..6a8cdf5 100644
--- a/examples/Makefile
+++ b/examples/Makefile
@@ -1,7 +1,7 @@
 CFLAGS=-O2 -g $(shell pkg-config --cflags libp11)
 LDFLAGS=$(shell pkg-config --libs libp11)
 
-all: auth getrandom
+all: auth decrypt getrandom
 
 clean:
-	rm auth getrandom
+	rm auth decrypt getrandom
diff --git a/examples/decrypt.c b/examples/decrypt.c
new file mode 100644
index 0000000..7d8fcaf
--- /dev/null
+++ b/examples/decrypt.c
@@ -0,0 +1,227 @@
+/* libp11 example code: auth.c
+ *
+ * This examply simply connects to your smart card
+ * and does a public key authentication.
+ *
+ * Feel free to copy all of the code as needed.
+ *
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <termios.h>
+#include <stdio.h>
+#include <string.h>
+#include <libp11.h>
+
+#define RANDOM_SOURCE "/dev/urandom"
+#define RANDOM_SIZE 128
+#define MAX_SIGSIZE 256
+
+int main(int argc, char *argv[])
+{
+	PKCS11_CTX *ctx;
+	PKCS11_SLOT *slots, *slot;
+	PKCS11_CERT *certs;
+	
+	PKCS11_KEY *authkey;
+	PKCS11_CERT *authcert;
+	EVP_PKEY *pubkey;
+
+	unsigned char *random, *encrypted, *decrypted;
+
+	char password[20];
+	int rc = 0, fd, i, len;
+	unsigned int nslots, ncerts, siglen;
+
+	if (argc != 2) {
+		fprintf(stderr, "usage: auth /usr/lib/opensc-pkcs11.so\n");
+		return 1;
+	}
+
+	ctx = PKCS11_CTX_new();
+
+	/* load pkcs #11 module */
+	rc = PKCS11_CTX_load(ctx, argv[1]);
+	if (rc) {
+		fprintf(stderr, "loading pkcs11 engine failed: %s\n",
+			ERR_reason_error_string(ERR_get_error()));
+		rc = 1;
+		goto nolib;
+	}
+
+	/* get information on all slots */
+	rc = PKCS11_enumerate_slots(ctx, &slots, &nslots);
+	if (rc < 0) {
+		fprintf(stderr, "no slots available\n");
+		rc = 2;
+		goto noslots;
+	}
+
+	/* get first slot with a token */
+	slot = PKCS11_find_token(ctx, slots, nslots);
+	if (!slot || !slot->token) {
+		fprintf(stderr, "no token available\n");
+		rc = 3;
+		goto notoken;
+	}
+	printf("Slot manufacturer......: %s\n", slot->manufacturer);
+	printf("Slot description.......: %s\n", slot->description);
+	printf("Slot token label.......: %s\n", slot->token->label);
+	printf("Slot token manufacturer: %s\n", slot->token->manufacturer);
+	printf("Slot token model.......: %s\n", slot->token->model);
+	printf("Slot token serialnr....: %s\n", slot->token->serialnr);
+
+	/* get all certs */
+	rc = PKCS11_enumerate_certs(slot->token, &certs, &ncerts);
+	if (rc) {
+		fprintf(stderr, "PKCS11_enumerate_certs failed\n");
+		goto failed;
+	}
+	if (ncerts <= 0) {
+		fprintf(stderr, "no certificates found\n");
+		goto failed;
+	}
+
+	/* use the first cert */
+	authcert=&certs[0];
+
+	/* get random bytes */
+	random = malloc(RANDOM_SIZE);
+	if (!random)
+		goto failed;
+
+	fd = open(RANDOM_SOURCE, O_RDONLY);
+	if (fd < 0) {
+		fprintf(stderr, "fatal: cannot open RANDOM_SOURCE: %s\n",
+				strerror(errno));
+		goto failed;
+	}
+
+	rc = read(fd, random, RANDOM_SIZE);
+	if (rc < 0) {
+		fprintf(stderr, "fatal: read from random source failed: %s\n",
+			strerror(errno));
+		close(fd);
+		goto failed;
+	}
+
+	if (rc < RANDOM_SIZE) {
+		fprintf(stderr, "fatal: read returned less than %d<%d bytes\n",
+		       rc, RANDOM_SIZE);
+		close(fd);
+		goto failed;
+	}
+
+	close(fd);
+
+	/* get RSA key */
+	pubkey = X509_get_pubkey(authcert->x509);
+	if (pubkey == NULL) {
+		fprintf(stderr, "could not extract public key\n");
+		goto failed;
+	}
+
+	/* allocate destination buffer */
+	encrypted = malloc(RSA_size(pubkey->pkey.rsa));
+	if (!encrypted) {
+		fprintf(stderr,"out of memory for encrypted data");
+		goto failed;
+	}
+
+	/* use public key for encryption */
+	rc = RSA_public_encrypt(RANDOM_SIZE, random, encrypted,
+			pubkey->pkey.rsa, RSA_PKCS1_PADDING);
+	if (rc != 1) {
+		fprintf(stderr, "fatal: RSA_public_encrypt failed\n");
+		goto failed;
+	}
+
+	/* now decrypt */
+	if (!slot->token->loginRequired)
+		goto loggedin;
+
+	/* get password */
+	struct termios old, new;
+	int nread;
+
+	/* Turn echoing off and fail if we can't. */
+	if (tcgetattr(0, &old) != 0)
+		goto failed;
+
+	new = old;
+	new.c_lflag &= ~ECHO;
+	if (tcsetattr(0, TCSAFLUSH, &new) != 0)
+		goto failed;
+
+	/* Read the password. */
+	printf("Password for token %.32s: ", slot->token->label);
+	fgets(password, sizeof(password), stdin);
+
+	/* Restore terminal. */
+	(void)tcsetattr(0, TCSAFLUSH, &old);
+
+	/* strip tailing \n from password */
+	rc = strlen(password);
+	if (rc <= 0)
+		goto failed;
+	password[rc-1]=0;
+
+	/* perform pkcs #11 login */
+	rc = PKCS11_login(slot, 0, password);
+	memset(password, 0, strlen(password));
+	if (rc != 0) {
+		fprintf(stderr, "PKCS11_login failed\n");
+		goto failed;
+	}
+
+      loggedin:
+
+	authkey = PKCS11_find_key(authcert);
+	if (!authkey) {
+		fprintf(stderr, "no key matching certificate available\n");
+		goto failed;
+	}
+
+	/* allocate space for decrypted. */
+	decrypted = malloc(RANDOM_SIZE);
+	if (!decrypted)
+		goto failed;
+
+	rc = PKCS11_private_decrypt(RSA_size(pubkey->pkey.rsa), encrypted,
+			decrypted, authkey, RSA_PKCS1_PADDING);
+	if (rc != 1) {
+		fprintf(stderr, "fatal: PKCS11_private_decrypt failed\n");
+		goto failed;
+	}
+
+	/* check if original matches decypted */
+	if (memcmp(random, decrypted, RANDOM_SIZE) != 0) {
+		fprintf(stderr, "fatal: decrypted data does not match original\n");
+		goto failed;
+	}
+
+	PKCS11_release_all_slots(ctx, slots, nslots);
+	PKCS11_CTX_unload(ctx);
+	PKCS11_CTX_free(ctx);
+
+	printf("decryption successfull.\n");
+	return 0;
+
+
+      failed:
+      norandom:
+      notoken:
+	PKCS11_release_all_slots(ctx, slots, nslots);
+
+      noslots:
+	PKCS11_CTX_unload(ctx);
+
+      nolib:
+	PKCS11_CTX_free(ctx);
+	
+
+	printf("decryption failed.\n");
+	return 1;
+}

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