Delete bundled copy of NSS and replace with README.

nss/lib/freebl/cts.c

Index: nss/lib/freebl/cts.c
diff --git a/nss/lib/freebl/cts.c b/nss/lib/freebl/cts.c
deleted file mode 100644
index 984e05b95071021fe5869ce305b7c3885015f832..0000000000000000000000000000000000000000
--- a/nss/lib/freebl/cts.c
+++ /dev/null
@@ -1,301 +0,0 @@
-/* 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 "blapit.h"
-#include "blapii.h"
-#include "cts.h"
-#include "secerr.h"
-
-struct CTSContextStr {
-    freeblCipherFunc cipher;
-    void *context;
-    /* iv stores the last ciphertext block of the previous message.
-     * Only used by decrypt. */
-    unsigned char iv[MAX_BLOCK_SIZE];
-};
-
-CTSContext *
-CTS_CreateContext(void *context, freeblCipherFunc cipher,
-		  const unsigned char *iv, unsigned int blocksize)
-{
-    CTSContext  *cts;
-
-    if (blocksize > MAX_BLOCK_SIZE) {
-	PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
-	return NULL;
-    }
-    cts = PORT_ZNew(CTSContext);
-    if (cts == NULL) {
-	return NULL;
-    }
-    PORT_Memcpy(cts->iv, iv, blocksize);
-    cts->cipher = cipher;
-    cts->context = context;
-    return cts;
-}
-
-void
-CTS_DestroyContext(CTSContext *cts, PRBool freeit)
-{
-    if (freeit) {
-	PORT_Free(cts);
-    }
-}
-	
-/*
- * See addemdum to NIST SP 800-38A
- * Generically handle cipher text stealing. Basically this is doing CBC
- * operations except someone can pass us a partial block.
- *
- *  Output Order:
- *  CS-1:  C1||C2||C3..Cn-1(could be partial)||Cn   (NIST)
- *  CS-2: pad == 0 C1||C2||C3...Cn-1(is full)||Cn   (Schneier)
- *  CS-2: pad != 0 C1||C2||C3...Cn||Cn-1(is partial)(Schneier)
- *  CS-3: C1||C2||C3...Cn||Cn-1(could be partial)   (Kerberos)
- *
- * The characteristics of these three options:
- *  - NIST & Schneier (CS-1 & CS-2) are identical to CBC if there are no
- * partial blocks on input.
- *  - Scheier and Kerberos (CS-2 and CS-3) have no embedded partial blocks,
- * which make decoding easier.
- *  - NIST & Kerberos (CS-1 and CS-3) have consistent block order independent
- * of padding.
- *
- * PKCS #11 did not specify which version to implement, but points to the NIST
- * spec, so this code implements CTS-CS-1 from NIST.
- *
- * To convert the returned buffer to:
- *   CS-2 (Schneier): do
- *       unsigned char tmp[MAX_BLOCK_SIZE];
- *       pad = *outlen % blocksize;
- *       if (pad) {
- *          memcpy(tmp, outbuf+*outlen-blocksize, blocksize);
- *          memcpy(outbuf+*outlen-pad,outbuf+*outlen-blocksize-pad, pad);
- *	    memcpy(outbuf+*outlen-blocksize-pad, tmp, blocksize);
- *       }
- *   CS-3 (Kerberos): do
- *       unsigned char tmp[MAX_BLOCK_SIZE];
- *       pad = *outlen % blocksize;
- *       if (pad == 0) {
- *           pad = blocksize;
- *       }
- *       memcpy(tmp, outbuf+*outlen-blocksize, blocksize);
- *       memcpy(outbuf+*outlen-pad,outbuf+*outlen-blocksize-pad, pad);
- *	 memcpy(outbuf+*outlen-blocksize-pad, tmp, blocksize);
- */
-SECStatus
-CTS_EncryptUpdate(CTSContext *cts, unsigned char *outbuf,
-		unsigned int *outlen, unsigned int maxout,
-		const unsigned char *inbuf, unsigned int inlen,
-		unsigned int blocksize)
-{
-    unsigned char lastBlock[MAX_BLOCK_SIZE];
-    unsigned int tmp;
-    int fullblocks;
-    int written;
-    SECStatus rv;
-
-    if (inlen < blocksize) {
-	PORT_SetError(SEC_ERROR_INPUT_LEN);
-	return SECFailure;
-    }
-
-    if (maxout < inlen) {
-	*outlen = inlen;
-	PORT_SetError(SEC_ERROR_OUTPUT_LEN);
-	return SECFailure;
-    }
-    fullblocks = (inlen/blocksize)*blocksize;
-    rv = (*cts->cipher)(cts->context, outbuf, outlen, maxout, inbuf,
-	 fullblocks, blocksize);
-    if (rv != SECSuccess) {
-	return SECFailure;
-    }
-    *outlen = fullblocks; /* AES low level doesn't set outlen */
-    inbuf += fullblocks;
-    inlen -= fullblocks;
-    if (inlen == 0) {
-	return SECSuccess;
-    }
-    written = *outlen - (blocksize - inlen);
-    outbuf += written;
-    maxout -= written;
-
-    /*
-     * here's the CTS magic, we pad our final block with zeros,
-     * then do a CBC encrypt. CBC will xor our plain text with
-     * the previous block (Cn-1), capturing part of that block (Cn-1**) as it
-     * xors with the zero pad. We then write this full block, overwritting
-     * (Cn-1**) in our buffer. This allows us to have input data == output
-     * data since Cn contains enough information to reconver Cn-1** when
-     * we decrypt (at the cost of some complexity as you can see in decrypt
-     * below */
-    PORT_Memcpy(lastBlock, inbuf, inlen);
-    PORT_Memset(lastBlock + inlen, 0, blocksize - inlen);
-    rv = (*cts->cipher)(cts->context, outbuf, &tmp, maxout, lastBlock,
-			blocksize, blocksize);
-    PORT_Memset(lastBlock, 0, blocksize);
-    if (rv == SECSuccess) {
-	*outlen = written + blocksize;
-    }
-    return rv;
-}
-
-
-#define XOR_BLOCK(x,y,count) for(i=0; i < count; i++) x[i] = x[i] ^ y[i]
-
-/*
- * See addemdum to NIST SP 800-38A
- * Decrypt, Expect CS-1: input. See the comment on the encrypt side
- * to understand what CS-2 and CS-3 mean.
- *
- * To convert the input buffer to CS-1 from ...
- *   CS-2 (Schneier): do
- *       unsigned char tmp[MAX_BLOCK_SIZE];
- *       pad = inlen % blocksize;
- *       if (pad) {
- *          memcpy(tmp, inbuf+inlen-blocksize-pad, blocksize);
- *          memcpy(inbuf+inlen-blocksize-pad,inbuf+inlen-pad, pad);
- *	    memcpy(inbuf+inlen-blocksize, tmp, blocksize);
- *       }
- *   CS-3 (Kerberos): do
- *       unsigned char tmp[MAX_BLOCK_SIZE];
- *       pad = inlen % blocksize;
- *       if (pad == 0) {
- *           pad = blocksize;
- *       }
- *       memcpy(tmp, inbuf+inlen-blocksize-pad, blocksize);
- *       memcpy(inbuf+inlen-blocksize-pad,inbuf+inlen-pad, pad);
- *	 memcpy(inbuf+inlen-blocksize, tmp, blocksize);
- */
-SECStatus
-CTS_DecryptUpdate(CTSContext *cts, unsigned char *outbuf,
-		unsigned int *outlen, unsigned int maxout,
-		const unsigned char *inbuf, unsigned int inlen,
-		unsigned int blocksize)
-{
-    unsigned char *Pn;
-    unsigned char Cn_2[MAX_BLOCK_SIZE]; /* block Cn-2 */
-    unsigned char Cn_1[MAX_BLOCK_SIZE]; /* block Cn-1 */
-    unsigned char Cn[MAX_BLOCK_SIZE];   /* block Cn   */
-    unsigned char lastBlock[MAX_BLOCK_SIZE];
-    const unsigned char *tmp;
-    unsigned int tmpLen;
-    unsigned int fullblocks, pad;
-    unsigned int i;
-    SECStatus rv;
-
-    if (inlen < blocksize) {
-	PORT_SetError(SEC_ERROR_INPUT_LEN);
-	return SECFailure;
-    }
-
-    if (maxout < inlen) {
-	*outlen = inlen;
-	PORT_SetError(SEC_ERROR_OUTPUT_LEN);
-	return SECFailure;
-    }
-
-    fullblocks = (inlen/blocksize)*blocksize;
-
-    /* even though we expect the input to be CS-1, CS-2 is easier to parse,
-     * so convert to CS-2 immediately. NOTE: this is the same code as in
-     * the comment for encrypt. NOTE2: since we can't modify inbuf unless
-     * inbuf and outbuf overlap, just copy inbuf to outbuf and modify it there
-     */
-    pad = inlen - fullblocks;
-    if (pad != 0) {
-	if (inbuf != outbuf) {
-	    memcpy(outbuf, inbuf, inlen);
-	    /* keep the names so we logically know how we are using the
-	     * buffers */
-	    inbuf = outbuf;
-	}
-	memcpy(lastBlock, inbuf+inlen-blocksize, blocksize);
-	/* we know inbuf == outbuf now, inbuf is declared const and can't
-	 * be the target, so use outbuf for the target here */
-	memcpy(outbuf+inlen-pad, inbuf+inlen-blocksize-pad, pad);
-	memcpy(outbuf+inlen-blocksize-pad, lastBlock, blocksize);
-    }
-    /* save the previous to last block so we can undo the misordered
-     * chaining */
-    tmp =  (fullblocks < blocksize*2) ? cts->iv :
-			inbuf+fullblocks-blocksize*2;
-    PORT_Memcpy(Cn_2, tmp, blocksize);
-    PORT_Memcpy(Cn, inbuf+fullblocks-blocksize, blocksize);
-    rv = (*cts->cipher)(cts->context, outbuf, outlen, maxout, inbuf,
-	 fullblocks, blocksize);
-    if (rv != SECSuccess) {
-	return SECFailure;
-    }
-    *outlen = fullblocks; /* AES low level doesn't set outlen */
-    inbuf += fullblocks;
-    inlen -= fullblocks;
-    if (inlen == 0) {
-	return SECSuccess;
-    }
-    outbuf += fullblocks;
-
-    /* recover the stolen text */
-    PORT_Memset(lastBlock, 0, blocksize);
-    PORT_Memcpy(lastBlock, inbuf, inlen);
-    PORT_Memcpy(Cn_1, inbuf, inlen);
-    Pn = outbuf-blocksize;
-    /* inbuf points to Cn-1* in the input buffer */
-    /* NOTE: below there are 2 sections marked "make up for the out of order
-     * cbc decryption". You may ask, what is going on here.
-     *   Short answer: CBC automatically xors the plain text with the previous
-     * encrypted block. We are decrypting the last 2 blocks out of order, so
-     * we have to 'back out' the decrypt xor and 'add back' the encrypt xor.
-     *   Long answer: When we encrypted, we encrypted as follows:
-     *       Pn-2, Pn-1, (Pn || 0), but on decryption we can't
-     *  decrypt Cn-1 until we decrypt Cn because part of Cn-1 is stored in
-     *  Cn (see below).  So above we decrypted all the full blocks:
-     *       Cn-2, Cn,
-     *  to get:
-     *       Pn-2, Pn, Except that Pn is not yet corect. On encrypt, we
-     *  xor'd Pn || 0  with Cn-1, but on decrypt we xor'd it with Cn-2
-     *  To recover Pn, we xor the block with Cn-1* || 0 (in last block) and
-     *  Cn-2 to get Pn || Cn-1**. Pn can then be written to the output buffer
-     *  and we can now reunite Cn-1. With the full Cn-1 we can decrypt it,
-     *  but now decrypt is going to xor the decrypted data with Cn instead of
-     *  Cn-2. xoring Cn and Cn-2 restores the original Pn-1 and we can now
-     *  write that oout to the buffer */
-
-    /* make up for the out of order CBC decryption */
-    XOR_BLOCK(lastBlock, Cn_2, blocksize);
-    XOR_BLOCK(lastBlock, Pn, blocksize);
-    /* last buf now has Pn || Cn-1**, copy out Pn */
-    PORT_Memcpy(outbuf, lastBlock, inlen);
-    *outlen += inlen;
-    /* copy Cn-1* into last buf to recover Cn-1 */
-    PORT_Memcpy(lastBlock, Cn_1, inlen);
-    /* note: because Cn and Cn-1 were out of order, our pointer to Pn also
-     * points to where Pn-1 needs to reside. From here on out read Pn in
-     * the code as really Pn-1. */
-    rv = (*cts->cipher)(cts->context, Pn, &tmpLen, blocksize, lastBlock,
-	 blocksize, blocksize);
-    if (rv != SECSuccess) {
-	return SECFailure;
-    }
-    /* make up for the out of order CBC decryption */
-    XOR_BLOCK(Pn, Cn_2, blocksize);
-    XOR_BLOCK(Pn, Cn, blocksize);
-    /* reset iv to Cn  */
-    PORT_Memcpy(cts->iv, Cn, blocksize);
-    /* This makes Cn the last block for the next decrypt operation, which
-     * matches the encrypt. We don't care about the contexts of last block,
-     * only the side effect of setting the internal IV */
-    (void) (*cts->cipher)(cts->context, lastBlock, &tmpLen, blocksize, Cn,
-		blocksize, blocksize);
-    /* clear last block. At this point last block contains Pn xor Cn_1 xor
-     * Cn_2, both of with an attacker would know, so we need to clear this
-     * buffer out */
-    PORT_Memset(lastBlock, 0, blocksize);
-    /* Cn, Cn_1, and Cn_2 have encrypted data, so no need to clear them */
-    return SECSuccess;
-}