Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 323 insertions, 0 deletions

diff --git a/security/nss/lib/freebl/cmac.c b/security/nss/lib/freebl/cmac.c
new file mode 100644
index 0000000000..222cef1b4c
--- /dev/null
+++ b/security/nss/lib/freebl/cmac.c
@@ -0,0 +1,323 @@
+/* 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 "rijndael.h"
+#include "blapi.h"
+#include "cmac.h"
+#include "secerr.h"
+#include "nspr.h"
+
+struct CMACContextStr {
+    /* Information about the block cipher to use internally. The cipher should
+     * be placed in ECB mode so that we can use it to directly encrypt blocks.
+     *
+     *
+     * To add a new cipher, add an entry to CMACCipher, update CMAC_Init,
+     * cmac_Encrypt, and CMAC_Destroy methods to handle the new cipher, and
+     * add a new Context pointer to the cipher union with the correct type. */
+    CMACCipher cipherType;
+    union {
+        AESContext *aes;
+    } cipher;
+    unsigned int blockSize;
+
+    /* Internal keys which are conditionally used by the algorithm. Derived
+     * from encrypting the NULL block. We leave the storing of (and the
+     * cleanup of) the CMAC key to the underlying block cipher. */
+    unsigned char k1[MAX_BLOCK_SIZE];
+    unsigned char k2[MAX_BLOCK_SIZE];
+
+    /* When Update is called with data which isn't a multiple of the block
+     * size, we need a place to put it. HMAC handles this by passing it to
+     * the underlying hash function right away; we can't do that as the
+     * contract on the cipher object is different. */
+    unsigned int partialIndex;
+    unsigned char partialBlock[MAX_BLOCK_SIZE];
+
+    /* Last encrypted block. This gets xor-ed with partialBlock prior to
+     * encrypting it. NIST defines this to be the empty string to begin. */
+    unsigned char lastBlock[MAX_BLOCK_SIZE];
+};
+
+static void
+cmac_ShiftLeftOne(unsigned char *out, const unsigned char *in, int length)
+{
+    int i = 0;
+    for (; i < length - 1; i++) {
+        out[i] = in[i] << 1;
+        out[i] |= in[i + 1] >> 7;
+    }
+    out[i] = in[i] << 1;
+}
+
+static SECStatus
+cmac_Encrypt(CMACContext *ctx, unsigned char *output,
+             const unsigned char *input,
+             unsigned int inputLen)
+{
+    if (ctx->cipherType == CMAC_AES) {
+        unsigned int tmpOutputLen;
+        SECStatus rv = AES_Encrypt(ctx->cipher.aes, output, &tmpOutputLen,
+                                   ctx->blockSize, input, inputLen);
+
+        /* Assumption: AES_Encrypt (when in ECB mode) always returns an
+         * output of length equal to blockSize (what was pass as the value
+         * of the maxOutputLen parameter). */
+        PORT_Assert(tmpOutputLen == ctx->blockSize);
+        return rv;
+    }
+
+    return SECFailure;
+}
+
+/* NIST SP.800-38B, 6.1 Subkey Generation */
+static SECStatus
+cmac_GenerateSubkeys(CMACContext *ctx)
+{
+    unsigned char null_block[MAX_BLOCK_SIZE] = { 0 };
+    unsigned char L[MAX_BLOCK_SIZE];
+    unsigned char v;
+    unsigned char i;
+
+    /* Step 1: L = AES(key, null_block) */
+    if (cmac_Encrypt(ctx, L, null_block, ctx->blockSize) != SECSuccess) {
+        return SECFailure;
+    }
+
+    /* In the following, some effort has been made to be constant time. Rather
+     * than conditioning on the value of the MSB (of L or K1), we use the loop
+     * to build a mask for the conditional constant. */
+
+    /* Step 2: If MSB(L) = 0, K1 = L << 1. Else, K1 = (L << 1) ^ R_b. */
+    cmac_ShiftLeftOne(ctx->k1, L, ctx->blockSize);
+    v = L[0] >> 7;
+    for (i = 1; i <= 7; i <<= 1) {
+        v |= (v << i);
+    }
+    ctx->k1[ctx->blockSize - 1] ^= (0x87 & v);
+
+    /* Step 3: If MSB(K1) = 0, K2 = K1 << 1. Else, K2 = (K1 <, 1) ^ R_b. */
+    cmac_ShiftLeftOne(ctx->k2, ctx->k1, ctx->blockSize);
+    v = ctx->k1[0] >> 7;
+    for (i = 1; i <= 7; i <<= 1) {
+        v |= (v << i);
+    }
+    ctx->k2[ctx->blockSize - 1] ^= (0x87 & v);
+
+    /* Any intermediate value in the computation of the subkey shall be
+     * secret. */
+    PORT_Memset(null_block, 0, MAX_BLOCK_SIZE);
+    PORT_Memset(L, 0, MAX_BLOCK_SIZE);
+
+    /* Step 4: Return the values. */
+    return SECSuccess;
+}
+
+/* NIST SP.800-38B, 6.2 MAC Generation step 6 */
+static SECStatus
+cmac_UpdateState(CMACContext *ctx)
+{
+    if (ctx == NULL || ctx->partialIndex != ctx->blockSize) {
+        PORT_SetError(SEC_ERROR_INVALID_ARGS);
+        return SECFailure;
+    }
+
+    /* Step 6: C_i = CIPHER(key, C_{i-1} ^ M_i)  for 1 <= i <= n, and
+     *         C_0 is defined as the empty string. */
+
+    for (unsigned int index = 0; index < ctx->blockSize; index++) {
+        ctx->partialBlock[index] ^= ctx->lastBlock[index];
+    }
+
+    return cmac_Encrypt(ctx, ctx->lastBlock, ctx->partialBlock, ctx->blockSize);
+}
+
+SECStatus
+CMAC_Init(CMACContext *ctx, CMACCipher type,
+          const unsigned char *key, unsigned int key_len)
+{
+    if (ctx == NULL) {
+        PORT_SetError(SEC_ERROR_NO_MEMORY);
+        return SECFailure;
+    }
+
+    /* We only currently support AES-CMAC. */
+    if (type != CMAC_AES) {
+        PORT_SetError(SEC_ERROR_INVALID_ARGS);
+        return SECFailure;
+    }
+
+    PORT_Memset(ctx, 0, sizeof(*ctx));
+
+    ctx->blockSize = AES_BLOCK_SIZE;
+    ctx->cipherType = CMAC_AES;
+    ctx->cipher.aes = AES_CreateContext(key, NULL, NSS_AES, 1, key_len,
+                                        ctx->blockSize);
+    if (ctx->cipher.aes == NULL) {
+        return SECFailure;
+    }
+
+    return CMAC_Begin(ctx);
+}
+
+CMACContext *
+CMAC_Create(CMACCipher type, const unsigned char *key,
+            unsigned int key_len)
+{
+    CMACContext *result = PORT_New(CMACContext);
+
+    if (CMAC_Init(result, type, key, key_len) != SECSuccess) {
+        CMAC_Destroy(result, PR_TRUE);
+        return NULL;
+    }
+
+    return result;
+}
+
+SECStatus
+CMAC_Begin(CMACContext *ctx)
+{
+    if (ctx == NULL) {
+        return SECFailure;
+    }
+
+    /* Ensure that our blockSize is less than the maximum. When this fails,
+     * a cipher with a larger block size was added and MAX_BLOCK_SIZE needs
+     * to be updated accordingly. */
+    PORT_Assert(ctx->blockSize <= MAX_BLOCK_SIZE);
+
+    if (cmac_GenerateSubkeys(ctx) != SECSuccess) {
+        return SECFailure;
+    }
+
+    /* Set the index to write partial blocks at to zero. This saves us from
+     * having to clear ctx->partialBlock. */
+    ctx->partialIndex = 0;
+
+    /* Step 5: Let C_0 = 0^b. */
+    PORT_Memset(ctx->lastBlock, 0, ctx->blockSize);
+
+    return SECSuccess;
+}
+
+/* NIST SP.800-38B, 6.2 MAC Generation */
+SECStatus
+CMAC_Update(CMACContext *ctx, const unsigned char *data,
+            unsigned int data_len)
+{
+    unsigned int data_index = 0;
+    if (ctx == NULL) {
+        PORT_SetError(SEC_ERROR_INVALID_ARGS);
+        return SECFailure;
+    }
+
+    if (data == NULL || data_len == 0) {
+        return SECSuccess;
+    }
+
+    /* Copy as many bytes from data into ctx->partialBlock as we can, up to
+     * the maximum of the remaining data and the remaining space in
+     * ctx->partialBlock.
+     *
+     * Note that we swap the order (encrypt *then* copy) because the last
+     * block is different from the rest. If we end on an even multiple of
+     * the block size, we have to be able to XOR it with K1. But we won't know
+     * that it is the last until CMAC_Finish is called (and by then, CMAC_Update
+     * has already returned). */
+    while (data_index < data_len) {
+        if (ctx->partialIndex == ctx->blockSize) {
+            if (cmac_UpdateState(ctx) != SECSuccess) {
+                return SECFailure;
+            }
+
+            ctx->partialIndex = 0;
+        }
+
+        unsigned int copy_len = data_len - data_index;
+        if (copy_len > (ctx->blockSize - ctx->partialIndex)) {
+            copy_len = ctx->blockSize - ctx->partialIndex;
+        }
+
+        PORT_Memcpy(ctx->partialBlock + ctx->partialIndex, data + data_index, copy_len);
+        data_index += copy_len;
+        ctx->partialIndex += copy_len;
+    }
+
+    return SECSuccess;
+}
+
+/* NIST SP.800-38B, 6.2 MAC Generation */
+SECStatus
+CMAC_Finish(CMACContext *ctx, unsigned char *result,
+            unsigned int *result_len,
+            unsigned int max_result_len)
+{
+    if (ctx == NULL || result == NULL || max_result_len == 0) {
+        PORT_SetError(SEC_ERROR_INVALID_ARGS);
+        return SECFailure;
+    }
+
+    if (max_result_len > ctx->blockSize) {
+        /* This is a weird situation. The PKCS #11 soft tokencode passes
+         * sizeof(result) here, which is hard-coded as SFTK_MAX_MAC_LENGTH.
+         * This later gets truncated to min(SFTK_MAX_MAC_LENGTH, requested). */
+        max_result_len = ctx->blockSize;
+    }
+
+    /* Step 4: If M_n* is a complete block, M_n = K1 ^ M_n*. Else,
+     * M_n = K2 ^ (M_n* || 10^j). */
+    if (ctx->partialIndex == ctx->blockSize) {
+        /* XOR in K1. */
+        for (unsigned int index = 0; index < ctx->blockSize; index++) {
+            ctx->partialBlock[index] ^= ctx->k1[index];
+        }
+    } else {
+        /* Use 10* padding on the partial block. */
+        ctx->partialBlock[ctx->partialIndex++] = 0x80;
+        PORT_Memset(ctx->partialBlock + ctx->partialIndex, 0,
+                    ctx->blockSize - ctx->partialIndex);
+        ctx->partialIndex = ctx->blockSize;
+
+        /* XOR in K2. */
+        for (unsigned int index = 0; index < ctx->blockSize; index++) {
+            ctx->partialBlock[index] ^= ctx->k2[index];
+        }
+    }
+
+    /* Encrypt the block. */
+    if (cmac_UpdateState(ctx) != SECSuccess) {
+        return SECFailure;
+    }
+
+    /* Step 7 & 8: T = MSB_tlen(C_n); return T. */
+    PORT_Memcpy(result, ctx->lastBlock, max_result_len);
+    if (result_len != NULL) {
+        *result_len = max_result_len;
+    }
+    return SECSuccess;
+}
+
+void
+CMAC_Destroy(CMACContext *ctx, PRBool free_it)
+{
+    if (ctx == NULL) {
+        return;
+    }
+
+    if (ctx->cipherType == CMAC_AES && ctx->cipher.aes != NULL) {
+        AES_DestroyContext(ctx->cipher.aes, PR_TRUE);
+    }
+
+    /* Destroy everything in the context. This includes sensitive data in
+     * K1, K2, and lastBlock. */
+    PORT_Memset(ctx, 0, sizeof(*ctx));
+
+    if (free_it == PR_TRUE) {
+        PORT_Free(ctx);
+    }
+}