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authorRobert Relyea <rrelyea@redhat.com>2011-06-28 17:28:22 +0200
committerAlon Levy <alevy@redhat.com>2011-07-22 18:05:36 +0300
commit010debef6111c6776cda7ad8d00737f2d1dbb164 (patch)
treeeffc9457c942c28dc448c381aeb71d8951b7c007 /libcacard
parentd1afc48b7cfdb4490f322d5d82a2aae6d545ec06 (diff)
libcacard/vcard_emul_nss: support cards lying about CKM_RSA_X_509 support
Some tokens claim to do CKM_RSA_X_509, but then choke when they try to do the actual operations. Try to detect those cases and treat them as if the token didn't claim support for X_509. Signed-off-by: Robert Relyea <rrelyea@redhat.com>
Diffstat (limited to 'libcacard')
-rw-r--r--libcacard/vcard_emul_nss.c133
1 files changed, 127 insertions, 6 deletions
diff --git a/libcacard/vcard_emul_nss.c b/libcacard/vcard_emul_nss.c
index f3db657d7..0f5095405 100644
--- a/libcacard/vcard_emul_nss.c
+++ b/libcacard/vcard_emul_nss.c
@@ -33,10 +33,17 @@
#include "vreader.h"
#include "vevent.h"
+typedef enum {
+ VCardEmulUnknown = -1,
+ VCardEmulFalse = 0,
+ VCardEmulTrue = 1
+} VCardEmulTriState;
+
struct VCardKeyStruct {
CERTCertificate *cert;
PK11SlotInfo *slot;
SECKEYPrivateKey *key;
+ VCardEmulTriState failedX509;
};
@@ -140,6 +147,7 @@ vcard_emul_make_key(PK11SlotInfo *slot, CERTCertificate *cert)
/* NOTE: the cert is a temp cert, not necessarily the cert in the token,
* use the DER version of this function */
key->key = PK11_FindKeyByDERCert(slot, cert, NULL);
+ key->failedX509 = VCardEmulUnknown;
return key;
}
@@ -208,13 +216,23 @@ vcard_emul_rsa_op(VCard *card, VCardKey *key,
{
SECKEYPrivateKey *priv_key;
unsigned signature_len;
+ PK11SlotInfo *slot;
SECStatus rv;
+ unsigned char buf[2048];
+ unsigned char *bp = NULL;
+ int pad_len;
+ vcard_7816_status_t ret = VCARD7816_STATUS_SUCCESS;
if ((!nss_emul_init) || (key == NULL)) {
/* couldn't get the key, indicate that we aren't logged in */
return VCARD7816_STATUS_ERROR_CONDITION_NOT_SATISFIED;
}
priv_key = vcard_emul_get_nss_key(key);
+ if (priv_key == NULL) {
+ /* couldn't get the key, indicate that we aren't logged in */
+ return VCARD7816_STATUS_ERROR_CONDITION_NOT_SATISFIED;
+ }
+ slot = vcard_emul_card_get_slot(card);
/*
* this is only true of the rsa signature
@@ -223,13 +241,116 @@ vcard_emul_rsa_op(VCard *card, VCardKey *key,
if (buffer_size != signature_len) {
return VCARD7816_STATUS_ERROR_DATA_INVALID;
}
- rv = PK11_PrivDecryptRaw(priv_key, buffer, &signature_len, signature_len,
- buffer, buffer_size);
- if (rv != SECSuccess) {
- return vcard_emul_map_error(PORT_GetError());
+ /* be able to handle larger keys if necessariy */
+ bp = &buf[0];
+ if (sizeof(buf) < signature_len) {
+ bp = qemu_malloc(signature_len);
}
- assert(buffer_size == signature_len);
- return VCARD7816_STATUS_SUCCESS;
+
+ /*
+ * do the raw operations. Some tokens claim to do CKM_RSA_X_509, but then
+ * choke when they try to do the actual operations. Try to detect
+ * those cases and treat them as if the token didn't claim support for
+ * X_509.
+ */
+ if (key->failedX509 != VCardEmulTrue
+ && PK11_DoesMechanism(slot, CKM_RSA_X_509)) {
+ rv = PK11_PrivDecryptRaw(priv_key, bp, &signature_len, signature_len,
+ buffer, buffer_size);
+ if (rv == SECSuccess) {
+ assert(buffer_size == signature_len);
+ memcpy(buffer, bp, signature_len);
+ key->failedX509 = VCardEmulFalse;
+ goto cleanup;
+ }
+ /*
+ * we've had a successful X509 operation, this failure must be
+ * somethine else
+ */
+ if (key->failedX509 == VCardEmulFalse) {
+ ret = vcard_emul_map_error(PORT_GetError());
+ goto cleanup;
+ }
+ /*
+ * key->failedX509 must be Unknown at this point, try the
+ * non-x_509 case
+ */
+ }
+ /* token does not support CKM_RSA_X509, emulate that with CKM_RSA_PKCS */
+ /* is this a PKCS #1 formatted signature? */
+ if ((buffer[0] == 0) && (buffer[1] == 1)) {
+ int i;
+
+ for (i = 2; i < buffer_size; i++) {
+ /* rsa signature pad */
+ if (buffer[i] != 0xff) {
+ break;
+ }
+ }
+ if ((i < buffer_size) && (buffer[i] == 0)) {
+ /* yes, we have a properly formated PKCS #1 signature */
+ /*
+ * NOTE: even if we accidentally got an encrypt buffer, which
+ * through shear luck started with 00, 01, ff, 00, it won't matter
+ * because the resulting Sign operation will effectively decrypt
+ * the real buffer.
+ */
+ SECItem signature;
+ SECItem hash;
+
+ i++;
+ hash.data = &buffer[i];
+ hash.len = buffer_size - i;
+ signature.data = bp;
+ signature.len = signature_len;
+ rv = PK11_Sign(priv_key, &signature, &hash);
+ if (rv != SECSuccess) {
+ ret = vcard_emul_map_error(PORT_GetError());
+ goto cleanup;
+ }
+ assert(buffer_size == signature.len);
+ memcpy(buffer, bp, signature.len);
+ /*
+ * we got here because either the X509 attempt failed, or the
+ * token couldn't do the X509 operation, in either case stay
+ * with the PKCS version for future operations on this key
+ */
+ key->failedX509 = VCardEmulTrue;
+ goto cleanup;
+ }
+ }
+ pad_len = buffer_size - signature_len;
+ assert(pad_len < 4);
+ /*
+ * OK now we've decrypted the payload, package it up in PKCS #1 for the
+ * upper layer.
+ */
+ buffer[0] = 0;
+ buffer[1] = 2; /* RSA_encrypt */
+ pad_len -= 3; /* format is 0 || 2 || pad || 0 || data */
+ /*
+ * padding for PKCS #1 encrypted data is a string of random bytes. The
+ * random butes protect against potential decryption attacks against RSA.
+ * Since PrivDecrypt has already stripped those bytes, we can't reconstruct
+ * them. This shouldn't matter to the upper level code which should just
+ * strip this code out anyway, so We'll pad with a constant 3.
+ */
+ memset(&buffer[2], 0x03, pad_len);
+ pad_len += 2; /* index to the end of the pad */
+ buffer[pad_len] = 0;
+ pad_len++; /* index to the start of the data */
+ memcpy(&buffer[pad_len], bp, signature_len);
+ /*
+ * we got here because either the X509 attempt failed, or the
+ * token couldn't do the X509 operation, in either case stay
+ * with the PKCS version for future operations on this key
+ */
+ key->failedX509 = VCardEmulTrue;
+cleanup:
+ if (bp != buf) {
+ qemu_free(bp);
+ }
+ return ret;
}
/*