1 files changed, 544 insertions, 0 deletions

diff --git a/ssh-pkcs11.c b/ssh-pkcs11.c
new file mode 100644
index 000000000..f82454329
--- /dev/null
+++ b/ssh-pkcs11.c
@@ -0,0 +1,544 @@
+/*
+ * Copyright (c) 2010 Markus Friedl.  All rights reserved.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+#include <sys/queue.h>
+#include <stdarg.h>
+#include <stdio.h>
+
+#include <string.h>
+#include <dlfcn.h>
+
+#define CRYPTOKI_COMPAT
+#include "pkcs11.h"
+
+#include "log.h"
+#include "misc.h"
+#include "key.h"
+#include "ssh-pkcs11.h"
+#include "xmalloc.h"
+
+struct pkcs11_slotinfo {
+	CK_TOKEN_INFO		token;
+	CK_SESSION_HANDLE	session;
+	int			logged_in;
+};
+
+struct pkcs11_provider {
+	char			*name;
+	void			*handle;
+	CK_FUNCTION_LIST	*function_list;
+	CK_INFO			info;
+	CK_ULONG		nslots;
+	CK_SLOT_ID		*slotlist;
+	struct pkcs11_slotinfo	*slotinfo;
+	int			valid;
+	int			refcount;
+	TAILQ_ENTRY(pkcs11_provider) next;
+};
+
+TAILQ_HEAD(, pkcs11_provider) pkcs11_providers;
+
+struct pkcs11_key {
+	struct pkcs11_provider	*provider;
+	CK_ULONG		slotidx;
+	int			(*orig_finish)(RSA *rsa);
+	RSA_METHOD		rsa_method;
+	char			*keyid;
+	int			keyid_len;
+};
+
+int pkcs11_interactive = 0;
+
+int
+pkcs11_init(int interactive)
+{
+	pkcs11_interactive = interactive;
+	TAILQ_INIT(&pkcs11_providers);
+	return (0);
+}
+
+/*
+ * finalize a provider shared libarary, it's no longer usable.
+ * however, there might still be keys referencing this provider,
+ * so the actuall freeing of memory is handled by pkcs11_provider_unref().
+ * this is called when a provider gets unregistered.
+ */
+static void
+pkcs11_provider_finalize(struct pkcs11_provider *p)
+{
+	CK_RV rv;
+	CK_ULONG i;
+
+	debug("pkcs11_provider_finalize: %p refcount %d valid %d",
+	    p, p->refcount, p->valid);
+	if (!p->valid)
+		return;
+	for (i = 0; i < p->nslots; i++) {
+		if (p->slotinfo[i].session &&
+		    (rv = p->function_list->C_CloseSession(
+		    p->slotinfo[i].session)) != CKR_OK)
+			error("C_CloseSession failed: %lu", rv);
+	}
+	if ((rv = p->function_list->C_Finalize(NULL)) != CKR_OK)
+		error("C_Finalize failed: %lu", rv);
+	p->valid = 0;
+	p->function_list = NULL;
+	dlclose(p->handle);
+}
+
+/*
+ * remove a reference to the provider.
+ * called when a key gets destroyed or when the provider is unregistered.
+ */
+static void
+pkcs11_provider_unref(struct pkcs11_provider *p)
+{
+	debug("pkcs11_provider_unref: %p refcount %d", p, p->refcount);
+	if (--p->refcount <= 0) {
+		if (p->valid)
+			error("pkcs11_provider_unref: %p still valid", p);
+		xfree(p->slotlist);
+		xfree(p->slotinfo);
+		xfree(p);
+	}
+}
+
+/* unregister all providers, keys might still point to the providers */
+void
+pkcs11_terminate(void)
+{
+	struct pkcs11_provider *p;
+
+	while ((p = TAILQ_FIRST(&pkcs11_providers)) != NULL) {
+		TAILQ_REMOVE(&pkcs11_providers, p, next);
+		pkcs11_provider_finalize(p);
+		pkcs11_provider_unref(p);
+	}
+}
+
+/* lookup provider by name */
+static struct pkcs11_provider *
+pkcs11_provider_lookup(char *provider_id)
+{
+	struct pkcs11_provider *p;
+
+	TAILQ_FOREACH(p, &pkcs11_providers, next) {
+		debug("check %p %s", p, p->name);
+		if (!strcmp(provider_id, p->name))
+			return (p);
+	}
+	return (NULL);
+}
+
+/* unregister provider by name */
+int
+pkcs11_del_provider(char *provider_id)
+{
+	struct pkcs11_provider *p;
+
+	if ((p = pkcs11_provider_lookup(provider_id)) != NULL) {
+		TAILQ_REMOVE(&pkcs11_providers, p, next);
+		pkcs11_provider_finalize(p);
+		pkcs11_provider_unref(p);
+		return (0);
+	}
+	return (-1);
+}
+
+/* openssl callback for freeing an RSA key */
+static int
+pkcs11_rsa_finish(RSA *rsa)
+{
+	struct pkcs11_key	*k11;
+	int rv = -1;
+
+	if ((k11 = RSA_get_app_data(rsa)) != NULL) {
+		if (k11->orig_finish)
+			rv = k11->orig_finish(rsa);
+		if (k11->provider)
+			pkcs11_provider_unref(k11->provider);
+		if (k11->keyid)
+			xfree(k11->keyid);
+		xfree(k11);
+	}
+	return (rv);
+}
+
+/* openssl callback doing the actual signing operation */
+static int
+pkcs11_rsa_private_encrypt(int flen, const u_char *from, u_char *to, RSA *rsa,
+    int padding)
+{
+	struct pkcs11_key	*k11;
+	struct pkcs11_slotinfo	*si;
+	CK_FUNCTION_LIST	*f;
+	CK_OBJECT_HANDLE	obj;
+	CK_ULONG		tlen = 0, nfound = 0;
+	CK_RV			rv;
+	CK_OBJECT_CLASS		private_key_class = CKO_PRIVATE_KEY;
+	CK_BBOOL		true = CK_TRUE;
+	CK_MECHANISM		mech = {
+		CKM_RSA_PKCS, NULL_PTR, 0
+	};
+	CK_ATTRIBUTE		key_filter[] = {
+		{CKA_CLASS, &private_key_class, sizeof(private_key_class) },
+		{CKA_ID, NULL, 0},
+		{CKA_SIGN, &true, sizeof(true) }
+	};
+	char			*pin, prompt[1024];
+	int			rval = -1;
+
+	if ((k11 = RSA_get_app_data(rsa)) == NULL) {
+		error("RSA_get_app_data failed for rsa %p", rsa);
+		return (-1);
+	}
+	if (!k11->provider || !k11->provider->valid) {
+		error("no pkcs11 (valid) provider for rsa %p", rsa);
+		return (-1);
+	}
+	f = k11->provider->function_list;
+	si = &k11->provider->slotinfo[k11->slotidx];
+	if ((si->token.flags & CKF_LOGIN_REQUIRED) && !si->logged_in) {
+		if (!pkcs11_interactive) {
+			error("need pin");
+			return (-1);
+		}
+		snprintf(prompt, sizeof(prompt), "Enter PIN for '%s': ",
+		    si->token.label);
+		pin = read_passphrase(prompt, RP_ALLOW_EOF);
+		if (pin == NULL)
+			return (-1);	/* bail out */
+		if ((rv = f->C_Login(si->session, CKU_USER, pin, strlen(pin)))
+		    != CKR_OK) {
+			xfree(pin);
+			error("C_Login failed: %lu", rv);
+			return (-1);
+		}
+		xfree(pin);
+		si->logged_in = 1;
+	}
+	key_filter[1].pValue = k11->keyid;
+	key_filter[1].ulValueLen = k11->keyid_len;
+	if ((rv = f->C_FindObjectsInit(si->session, key_filter, 3)) != CKR_OK) {
+		error("C_FindObjectsInit failed: %lu", rv);
+		return (-1);
+	}
+	if ((rv = f->C_FindObjects(si->session, &obj, 1, &nfound)) != CKR_OK ||
+	    nfound != 1) {
+		error("C_FindObjects failed (%lu nfound): %lu", nfound, rv);
+	} else if ((rv = f->C_SignInit(si->session, &mech, obj)) != CKR_OK) {
+		error("C_SignInit failed: %lu", rv);
+	} else {
+		/* XXX handle CKR_BUFFER_TOO_SMALL */
+		tlen = RSA_size(rsa);
+		rv = f->C_Sign(si->session, (CK_BYTE *)from, flen, to, &tlen);
+		if (rv == CKR_OK) 
+			rval = tlen;
+		else 
+			error("C_Sign failed: %lu", rv);
+	}
+	if ((rv = f->C_FindObjectsFinal(si->session)) != CKR_OK)
+		error("C_FindObjectsFinal failed: %lu", rv);
+	return (rval);
+}
+
+static int
+pkcs11_rsa_private_decrypt(int flen, const u_char *from, u_char *to, RSA *rsa,
+    int padding)
+{
+	return (-1);
+}
+
+/* redirect private key operations for rsa key to pkcs11 token */
+static int
+pkcs11_rsa_wrap(struct pkcs11_provider *provider, CK_ULONG slotidx,
+    CK_ATTRIBUTE *keyid_attrib, RSA *rsa)
+{
+	struct pkcs11_key	*k11;
+	const RSA_METHOD	*def = RSA_get_default_method();
+
+	k11 = xcalloc(1, sizeof(*k11));
+	k11->provider = provider;
+	provider->refcount++;	/* provider referenced by RSA key */
+	k11->slotidx = slotidx;
+	/* identify key object on smartcard */
+	k11->keyid_len = keyid_attrib->ulValueLen;
+	k11->keyid = xmalloc(k11->keyid_len);
+	memcpy(k11->keyid, keyid_attrib->pValue, k11->keyid_len);
+	k11->orig_finish = def->finish;
+	memcpy(&k11->rsa_method, def, sizeof(k11->rsa_method));
+	k11->rsa_method.name = "pkcs11";
+	k11->rsa_method.rsa_priv_enc = pkcs11_rsa_private_encrypt;
+	k11->rsa_method.rsa_priv_dec = pkcs11_rsa_private_decrypt;
+	k11->rsa_method.finish = pkcs11_rsa_finish;
+	RSA_set_method(rsa, &k11->rsa_method);
+	RSA_set_app_data(rsa, k11);
+	return (0);
+}
+
+/* remove trailing spaces */
+static void
+rmspace(char *buf, size_t len)
+{
+	size_t i;
+
+	if (!len)
+		return;
+	for (i = len - 1;  i > 0; i--)
+		if (i == len - 1 || buf[i] == ' ')
+			buf[i] = '\0';
+		else
+			break;
+}
+
+/*
+ * open a pkcs11 session and login if required.
+ * if pin == NULL we delay login until key use
+ */
+static int
+pkcs11_open_session(struct pkcs11_provider *p, CK_ULONG slotidx, char *pin)
+{
+	CK_RV			rv;
+	CK_FUNCTION_LIST	*f;
+	CK_SESSION_HANDLE	session;
+	int			login_required;
+
+	f = p->function_list;
+	login_required = p->slotinfo[slotidx].token.flags & CKF_LOGIN_REQUIRED;
+	if (pin && login_required && !strlen(pin)) {
+		error("pin required");
+		return (-1);
+	}
+	if ((rv = f->C_OpenSession(p->slotlist[slotidx], CKF_RW_SESSION|
+	    CKF_SERIAL_SESSION, NULL, NULL, &session))
+	    != CKR_OK) {
+		error("C_OpenSession failed: %lu", rv);
+		return (-1);
+	}
+	if (login_required && pin) {
+		if ((rv = f->C_Login(session, CKU_USER, pin, strlen(pin)))
+		    != CKR_OK) {
+			error("C_Login failed: %lu", rv);
+			if ((rv = f->C_CloseSession(session)) != CKR_OK)
+				error("C_CloseSession failed: %lu", rv);
+			return (-1);
+		}
+		p->slotinfo[slotidx].logged_in = 1;
+	}
+	p->slotinfo[slotidx].session = session;
+	return (0);
+}
+
+/*
+ * lookup public keys for token in slot identified by slotidx,
+ * add 'wrapped' public keys to the 'keysp' array and increment nkeys.
+ * keysp points to an (possibly empty) array with *nkeys keys.
+ */
+static int
+pkcs11_fetch_keys(struct pkcs11_provider *p, CK_ULONG slotidx, Key ***keysp,
+    int *nkeys)
+{
+	Key			*key;
+	RSA			*rsa;
+	int			i;
+	CK_RV			rv;
+	CK_OBJECT_HANDLE	obj;
+	CK_ULONG		nfound;
+	CK_SESSION_HANDLE	session;
+	CK_FUNCTION_LIST	*f;
+	CK_OBJECT_CLASS		pubkey_class = CKO_PUBLIC_KEY;
+	CK_ATTRIBUTE		pubkey_filter[] = {
+		{ CKA_CLASS, &pubkey_class, sizeof(pubkey_class) }
+	};
+	CK_ATTRIBUTE		attribs[] = {
+		{ CKA_ID, NULL, 0 },
+		{ CKA_MODULUS, NULL, 0 },
+		{ CKA_PUBLIC_EXPONENT, NULL, 0 }
+	};
+
+	f = p->function_list;
+	session = p->slotinfo[slotidx].session;
+	/* setup a filter the looks for public keys */
+	if ((rv = f->C_FindObjectsInit(session, pubkey_filter, 1)) != CKR_OK) {
+		error("C_FindObjectsInit failed: %lu", rv);
+		return (-1);
+	}
+	while (1) {
+		/* XXX 3 attributes in attribs[] */
+		for (i = 0; i < 3; i++) {
+			attribs[i].pValue = NULL;
+			attribs[i].ulValueLen = 0;
+		}
+		if ((rv = f->C_FindObjects(session, &obj, 1, &nfound)) != CKR_OK
+		    || nfound == 0)
+			break;
+		/* found a key, so figure out size of the attributes */
+		if ((rv = f->C_GetAttributeValue(session, obj, attribs, 3))
+		    != CKR_OK) {
+			error("C_GetAttributeValue failed: %lu", rv);
+			continue;
+		}
+		/* allocate buffers for attributes, XXX check ulValueLen? */
+		for (i = 0; i < 3; i++)
+			attribs[i].pValue = xmalloc(attribs[i].ulValueLen);
+		/* retrieve ID, modulus and public exponent of RSA key */
+		if ((rv = f->C_GetAttributeValue(session, obj, attribs, 3))
+		    != CKR_OK) {
+			error("C_GetAttributeValue failed: %lu", rv);
+		} else if ((rsa = RSA_new()) == NULL) {
+			error("RSA_new failed");
+		} else {
+			rsa->n = BN_bin2bn(attribs[1].pValue,
+			    attribs[1].ulValueLen, NULL);
+			rsa->e = BN_bin2bn(attribs[2].pValue,
+			    attribs[2].ulValueLen, NULL);
+			if (rsa->n && rsa->e &&
+			    pkcs11_rsa_wrap(p, slotidx, &attribs[0], rsa) == 0) {
+				key = key_new(KEY_UNSPEC);
+				key->rsa = rsa;
+				key->type = KEY_RSA;
+				key->flags |= KEY_FLAG_EXT;
+				/* expand key array and add key */
+				*keysp = xrealloc(*keysp, *nkeys + 1,
+				    sizeof(Key *));
+				(*keysp)[*nkeys] = key;
+				*nkeys = *nkeys + 1;
+				debug("have %d keys", *nkeys);
+			} else {
+				RSA_free(rsa);
+			}
+		}
+		for (i = 0; i < 3; i++)
+			xfree(attribs[i].pValue);
+	}
+	if ((rv = f->C_FindObjectsFinal(session)) != CKR_OK)
+		error("C_FindObjectsFinal failed: %lu", rv);
+	return (0);
+}
+
+/* register a new provider, fails if provider already exists */
+int
+pkcs11_add_provider(char *provider_id, char *pin, Key ***keyp)
+{
+	int nkeys, need_finalize = 0;
+	struct pkcs11_provider *p = NULL;
+	void *handle = NULL;
+	CK_RV (*getfunctionlist)(CK_FUNCTION_LIST **);
+	CK_RV rv;
+	CK_FUNCTION_LIST *f = NULL;
+	CK_TOKEN_INFO *token;
+	CK_ULONG i;
+
+	*keyp = NULL;
+	if (pkcs11_provider_lookup(provider_id) != NULL) {
+		error("provider already registered: %s", provider_id);
+		goto fail;
+	}
+	/* open shared pkcs11-libarary */
+	if ((handle = dlopen(provider_id, RTLD_NOW)) == NULL) {
+		error("dlopen %s failed: %s", provider_id, dlerror());
+		goto fail;
+	}
+	if ((getfunctionlist = dlsym(handle, "C_GetFunctionList")) == NULL) {
+		error("dlsym(C_GetFunctionList) failed: %s", dlerror());
+		goto fail;
+	}
+	p = xcalloc(1, sizeof(*p));
+	p->name = xstrdup(provider_id);
+	p->handle = handle;
+	/* setup the pkcs11 callbacks */
+	if ((rv = (*getfunctionlist)(&f)) != CKR_OK) {
+		error("C_GetFunctionList failed: %lu", rv);
+		goto fail;
+	}
+	p->function_list = f;
+	if ((rv = f->C_Initialize(NULL)) != CKR_OK) {
+		error("C_Initialize failed: %lu", rv);
+		goto fail;
+	}
+	need_finalize = 1;
+	if ((rv = f->C_GetInfo(&p->info)) != CKR_OK) {
+		error("C_GetInfo failed: %lu", rv);
+		goto fail;
+	}
+	rmspace(p->info.manufacturerID, sizeof(p->info.manufacturerID));
+	rmspace(p->info.libraryDescription, sizeof(p->info.libraryDescription));
+	debug("manufacturerID <%s> cryptokiVersion %d.%d"
+	    " libraryDescription <%s> libraryVersion %d.%d",
+	    p->info.manufacturerID,
+	    p->info.cryptokiVersion.major,
+	    p->info.cryptokiVersion.minor,
+	    p->info.libraryDescription,
+	    p->info.libraryVersion.major,
+	    p->info.libraryVersion.minor);
+	if ((rv = f->C_GetSlotList(CK_TRUE, NULL, &p->nslots)) != CKR_OK) {
+		error("C_GetSlotList failed: %lu", rv);
+		goto fail;
+	}
+	if (p->nslots == 0) {
+		error("no slots");
+		goto fail;
+	}
+	p->slotlist = xcalloc(p->nslots, sizeof(CK_SLOT_ID));
+	if ((rv = f->C_GetSlotList(CK_TRUE, p->slotlist, &p->nslots))
+	    != CKR_OK) {
+		error("C_GetSlotList failed: %lu", rv);
+		goto fail;
+	}
+	p->slotinfo = xcalloc(p->nslots, sizeof(struct pkcs11_slotinfo));
+	p->valid = 1;
+	nkeys = 0;
+	for (i = 0; i < p->nslots; i++) {
+		token = &p->slotinfo[i].token;
+		if ((rv = f->C_GetTokenInfo(p->slotlist[i], token))
+		    != CKR_OK) {
+			error("C_GetTokenInfo failed: %lu", rv);
+			continue;
+		}
+		rmspace(token->label, sizeof(token->label));
+		rmspace(token->manufacturerID, sizeof(token->manufacturerID));
+		rmspace(token->model, sizeof(token->model));
+		rmspace(token->serialNumber, sizeof(token->serialNumber));
+		debug("label <%s> manufacturerID <%s> model <%s> serial <%s>"
+		    " flags 0x%lx",
+		    token->label, token->manufacturerID, token->model,
+		    token->serialNumber, token->flags);
+		/* open session, login with pin and retrieve public keys */
+		if (pkcs11_open_session(p, i, pin) == 0)
+			pkcs11_fetch_keys(p, i, keyp, &nkeys);
+	}
+	if (nkeys > 0) {
+		TAILQ_INSERT_TAIL(&pkcs11_providers, p, next);
+		p->refcount++;	/* add to provider list */
+		return (nkeys);
+	}
+	error("no keys");
+	/* don't add the provider, since it does not have any keys */
+fail:
+	if (need_finalize && (rv = f->C_Finalize(NULL)) != CKR_OK)
+		error("C_Finalize failed: %lu", rv);
+	if (p) {
+		if (p->slotlist)
+			xfree(p->slotlist);
+		if (p->slotinfo)
+			xfree(p->slotinfo);
+		xfree(p);
+	}
+	if (handle)
+		dlclose(handle);
+	return (-1);
+}