Add GCM, CTR, and CTS modes to AES.

nss/mozilla/security/nss/lib/freebl/ctr.c

+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifdef FREEBL_NO_DEPEND
+#include "stubs.h"
+#endif
+#include "prtypes.h"
+#include "blapit.h"
+#include "blapii.h"
+#include "ctr.h"
+#include "pkcs11t.h"
+#include "secerr.h"
+
+SECStatus
+CTR_InitContext(CTRContext *ctr, void *context, freeblCipherFunc cipher,
+                const unsigned char *param, unsigned int blocksize)
+{
+    const CK_AES_CTR_PARAMS *ctrParams = (const CK_AES_CTR_PARAMS *)param;
+
+    if (ctrParams->ulCounterBits == 0 ||
+        ctrParams->ulCounterBits > blocksize * PR_BITS_PER_BYTE) {
+        PORT_SetError(SEC_ERROR_INVALID_ARGS);
+        return SECFailure;
+    }
+
+    /* Invariant: 0 < ctr->bufPtr <= blocksize */
+    ctr->bufPtr = blocksize; /* no unused data in the buffer */
+    ctr->cipher = cipher;
+    ctr->context = context;
+    ctr->counterBits = ctrParams->ulCounterBits;
+    if (blocksize > sizeof(ctr->counter) ||
+        blocksize > sizeof(ctrParams->cb)) {
+        PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
+        return SECFailure;
+    }
+    PORT_Memcpy(ctr->counter, ctrParams->cb, blocksize);
+    return SECSuccess;
+}
+
+CTRContext *
+CTR_CreateContext(void *context, freeblCipherFunc cipher,
+                  const unsigned char *param, unsigned int blocksize)
+{
+    CTRContext *ctr;
+    SECStatus rv;
+
+    /* first fill in the Counter context */
+    ctr = PORT_ZNew(CTRContext);
+    if (ctr == NULL) {
+        return NULL;
+    }
+    rv = CTR_InitContext(ctr, context, cipher, param, blocksize);
+    if (rv != SECSuccess) {
+        CTR_DestroyContext(ctr, PR_TRUE);
+        ctr = NULL;
+    }
+    return ctr;
+}
+
+void
+CTR_DestroyContext(CTRContext *ctr, PRBool freeit)
+{
+    PORT_Memset(ctr, 0, sizeof(CTRContext));
+    if (freeit) {
+        PORT_Free(ctr);
+    }
+}
+
+/*
+ * Used by counter mode. Increment the counter block. Not all bits in the
+ * counter block are part of the counter, counterBits tells how many bits
+ * are part of the counter. The counter block is blocksize long. It's a
+ * big endian value.
+ *
+ * XXX Does not handle counter rollover.
+ */
+static void
+ctr_GetNextCtr(unsigned char *counter, unsigned int counterBits,
+                unsigned int blocksize)
+{
+    unsigned char *counterPtr = counter + blocksize - 1;
+    unsigned char mask, count;
+
+    PORT_Assert(counterBits <= blocksize*PR_BITS_PER_BYTE);
+    while (counterBits >= PR_BITS_PER_BYTE) {
+        if (++(*(counterPtr--))) {
+            return;
+        }
+        counterBits -= PR_BITS_PER_BYTE;
+    }
+    if (counterBits == 0) {
+        return;
+    }
+    /* increment the final partial byte */
+    mask = (1 << counterBits)-1;
+    count = ++(*counterPtr) & mask;
+    *counterPtr = ((*counterPtr) & ~mask) | count;
+    return;
+}
+
+static void
+ctr_xor(unsigned char *target, const unsigned char *x,
+         const unsigned char *y, unsigned int count)
+{
+    unsigned int i;
+    for (i=0; i < count; i++) {
+        *target++ = *x++ ^ *y++;
+    }
+}
+
+SECStatus
+CTR_Update(CTRContext *ctr, unsigned char *outbuf,
+                unsigned int *outlen, unsigned int maxout,
+                const unsigned char *inbuf, unsigned int inlen,
+                unsigned int blocksize)
+{
+    unsigned int tmp;
+    SECStatus rv;
+
+    if (maxout < inlen) {
+        *outlen = inlen;
+        PORT_SetError(SEC_ERROR_OUTPUT_LEN);
+        return SECFailure;
+    }
+    *outlen = 0;
+    if (ctr->bufPtr != blocksize) {
+        unsigned int needed = PR_MIN(blocksize-ctr->bufPtr, inlen);
+        ctr_xor(outbuf, inbuf, ctr->buffer+ctr->bufPtr, needed);
+        ctr->bufPtr += needed;
+        outbuf += needed;
+        inbuf += needed;
+        *outlen += needed;
+        inlen -= needed;
+        if (inlen == 0) {
+            return SECSuccess;
+        }
+        PORT_Assert(ctr->bufPtr == blocksize);
+    }
+        
+    while (inlen >= blocksize) {
+        rv = (*ctr->cipher)(ctr->context, ctr->buffer, &tmp, blocksize,
+                        ctr->counter, blocksize, blocksize);
+        ctr_GetNextCtr(ctr->counter, ctr->counterBits, blocksize);
+        if (rv != SECSuccess) {
+            return SECFailure;
+        }
+        ctr_xor(outbuf, inbuf, ctr->buffer, blocksize);
+        outbuf += blocksize;
+        inbuf += blocksize;
+        *outlen += blocksize;
+        inlen -= blocksize;
+    }
+    if (inlen == 0) {
+        return SECSuccess;
+    }
+    rv = (*ctr->cipher)(ctr->context, ctr->buffer, &tmp, blocksize,
+                        ctr->counter, blocksize, blocksize);
+    ctr_GetNextCtr(ctr->counter, ctr->counterBits, blocksize);
+    if (rv != SECSuccess) {
+        return SECFailure;
+    }
+    ctr_xor(outbuf, inbuf, ctr->buffer, inlen);
+    ctr->bufPtr = inlen;
+    *outlen += inlen;
+    return SECSuccess;
+}