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-rw-r--r--security/nss/lib/cryptohi/dsautil.c271
1 files changed, 271 insertions, 0 deletions
diff --git a/security/nss/lib/cryptohi/dsautil.c b/security/nss/lib/cryptohi/dsautil.c
new file mode 100644
index 0000000000..cc575878f6
--- /dev/null
+++ b/security/nss/lib/cryptohi/dsautil.c
@@ -0,0 +1,271 @@
+/* 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/. */
+#include "cryptohi.h"
+#include "secasn1.h"
+#include "secitem.h"
+#include "prerr.h"
+
+#ifndef DSA1_SUBPRIME_LEN
+#define DSA1_SUBPRIME_LEN 20 /* bytes */
+#endif
+
+typedef struct {
+ SECItem r;
+ SECItem s;
+} DSA_ASN1Signature;
+
+const SEC_ASN1Template DSA_SignatureTemplate[] = {
+ { SEC_ASN1_SEQUENCE, 0, NULL, sizeof(DSA_ASN1Signature) },
+ { SEC_ASN1_INTEGER, offsetof(DSA_ASN1Signature, r) },
+ { SEC_ASN1_INTEGER, offsetof(DSA_ASN1Signature, s) },
+ { 0 }
+};
+
+/* Input is variable length multi-byte integer, MSB first (big endian).
+** Most signficant bit of first byte is NOT treated as a sign bit.
+** May be one or more leading bytes of zeros.
+** Output is variable length multi-byte integer, MSB first (big endian).
+** Most significant bit of first byte will be zero (positive sign bit)
+** No more than one leading zero byte.
+** Caller supplies dest buffer, and assures that it is long enough,
+** e.g. at least one byte longer that src's buffer.
+*/
+void
+DSAU_ConvertUnsignedToSigned(SECItem *dest, SECItem *src)
+{
+ unsigned char *pSrc = src->data;
+ unsigned char *pDst = dest->data;
+ unsigned int cntSrc = src->len;
+
+ /* skip any leading zeros. */
+ while (cntSrc && !(*pSrc)) {
+ pSrc++;
+ cntSrc--;
+ }
+ if (!cntSrc) {
+ *pDst = 0;
+ dest->len = 1;
+ return;
+ }
+
+ if (*pSrc & 0x80)
+ *pDst++ = 0;
+
+ PORT_Memcpy(pDst, pSrc, cntSrc);
+ dest->len = (pDst - dest->data) + cntSrc;
+}
+
+/*
+** src is a buffer holding a signed variable length integer.
+** dest is a buffer which will be filled with an unsigned integer,
+** MSB first (big endian) with leading zeros, so that the last byte
+** of src will be the LSB of the integer. The result will be exactly
+** the length specified by the caller in dest->len.
+** src can be shorter than dest. src can be longer than dst, but only
+** if the extra leading bytes are zeros.
+*/
+SECStatus
+DSAU_ConvertSignedToFixedUnsigned(SECItem *dest, SECItem *src)
+{
+ unsigned char *pSrc = src->data;
+ unsigned char *pDst = dest->data;
+ unsigned int cntSrc = src->len;
+ unsigned int cntDst = dest->len;
+ int zCount = cntDst - cntSrc;
+
+ if (zCount > 0) {
+ PORT_Memset(pDst, 0, zCount);
+ PORT_Memcpy(pDst + zCount, pSrc, cntSrc);
+ return SECSuccess;
+ }
+ if (zCount <= 0) {
+ /* Source is longer than destination. Check for leading zeros. */
+ while (zCount++ < 0) {
+ if (*pSrc++ != 0)
+ goto loser;
+ }
+ }
+ PORT_Memcpy(pDst, pSrc, cntDst);
+ return SECSuccess;
+
+loser:
+ PORT_SetError(PR_INVALID_ARGUMENT_ERROR);
+ return SECFailure;
+}
+
+/* src is a "raw" ECDSA or DSA signature, the first half contains r
+ * and the second half contains s. dest is the DER encoded signature.
+*/
+static SECStatus
+common_EncodeDerSig(SECItem *dest, SECItem *src)
+{
+ SECItem *item;
+ SECItem srcItem;
+ DSA_ASN1Signature sig;
+ unsigned char *signedR;
+ unsigned char *signedS;
+ unsigned int len;
+
+ /* Allocate memory with room for an extra byte that
+ * may be required if the top bit in the first byte
+ * is already set.
+ */
+ len = src->len / 2;
+ signedR = (unsigned char *)PORT_Alloc(len + 1);
+ if (!signedR)
+ return SECFailure;
+ signedS = (unsigned char *)PORT_ZAlloc(len + 1);
+ if (!signedS) {
+ if (signedR)
+ PORT_Free(signedR);
+ return SECFailure;
+ }
+
+ PORT_Memset(&sig, 0, sizeof(sig));
+
+ /* Must convert r and s from "unsigned" integers to "signed" integers.
+ ** If the high order bit of the first byte (MSB) is 1, then must
+ ** prepend with leading zero.
+ ** Must remove all but one leading zero byte from numbers.
+ */
+ sig.r.type = siUnsignedInteger;
+ sig.r.data = signedR;
+ sig.r.len = sizeof signedR;
+ sig.s.type = siUnsignedInteger;
+ sig.s.data = signedS;
+ sig.s.len = sizeof signedR;
+
+ srcItem.data = src->data;
+ srcItem.len = len;
+
+ DSAU_ConvertUnsignedToSigned(&sig.r, &srcItem);
+ srcItem.data += len;
+ DSAU_ConvertUnsignedToSigned(&sig.s, &srcItem);
+
+ item = SEC_ASN1EncodeItem(NULL, dest, &sig, DSA_SignatureTemplate);
+ if (signedR)
+ PORT_Free(signedR);
+ if (signedS)
+ PORT_Free(signedS);
+ if (item == NULL)
+ return SECFailure;
+
+ /* XXX leak item? */
+ return SECSuccess;
+}
+
+/* src is a DER-encoded ECDSA or DSA signature.
+** Returns a newly-allocated SECItem structure, pointing at a newly allocated
+** buffer containing the "raw" signature, which is len bytes of r,
+** followed by len bytes of s. For DSA, len is the length of q.
+** For ECDSA, len depends on the key size used to create the signature.
+*/
+static SECItem *
+common_DecodeDerSig(const SECItem *item, unsigned int len)
+{
+ SECItem *result = NULL;
+ PORTCheapArenaPool arena;
+ SECStatus status;
+ DSA_ASN1Signature sig;
+ SECItem dst;
+
+ PORT_Memset(&sig, 0, sizeof(sig));
+
+ /* Make enough room for r + s. */
+ PORT_InitCheapArena(&arena, PR_MAX(2 * MAX_ECKEY_LEN, DSA_MAX_SIGNATURE_LEN));
+
+ result = PORT_ZNew(SECItem);
+ if (result == NULL)
+ goto loser;
+
+ result->len = 2 * len;
+ result->data = (unsigned char *)PORT_Alloc(2 * len);
+ if (result->data == NULL)
+ goto loser;
+
+ sig.r.type = siUnsignedInteger;
+ sig.s.type = siUnsignedInteger;
+ status = SEC_QuickDERDecodeItem(&arena.arena, &sig, DSA_SignatureTemplate, item);
+ if (status != SECSuccess)
+ goto loser;
+
+ /* Convert sig.r and sig.s from variable length signed integers to
+ ** fixed length unsigned integers.
+ */
+ dst.data = result->data;
+ dst.len = len;
+ status = DSAU_ConvertSignedToFixedUnsigned(&dst, &sig.r);
+ if (status != SECSuccess)
+ goto loser;
+
+ dst.data += len;
+ status = DSAU_ConvertSignedToFixedUnsigned(&dst, &sig.s);
+ if (status != SECSuccess)
+ goto loser;
+
+done:
+ PORT_DestroyCheapArena(&arena);
+
+ return result;
+
+loser:
+ if (result != NULL) {
+ SECITEM_FreeItem(result, PR_TRUE);
+ result = NULL;
+ }
+ goto done;
+}
+
+/* src is a "raw" DSA1 signature, 20 bytes of r followed by 20 bytes of s.
+** dest is the signature DER encoded. ?
+*/
+SECStatus
+DSAU_EncodeDerSig(SECItem *dest, SECItem *src)
+{
+ PORT_Assert(src->len == 2 * DSA1_SUBPRIME_LEN);
+ if (src->len != 2 * DSA1_SUBPRIME_LEN) {
+ PORT_SetError(PR_INVALID_ARGUMENT_ERROR);
+ return SECFailure;
+ }
+
+ return common_EncodeDerSig(dest, src);
+}
+
+/* src is a "raw" DSA signature of length len (len/2 bytes of r followed
+** by len/2 bytes of s). dest is the signature DER encoded.
+*/
+SECStatus
+DSAU_EncodeDerSigWithLen(SECItem *dest, SECItem *src, unsigned int len)
+{
+
+ PORT_Assert((src->len == len) && (len % 2 == 0));
+ if ((src->len != len) || (src->len % 2 != 0)) {
+ PORT_SetError(PR_INVALID_ARGUMENT_ERROR);
+ return SECFailure;
+ }
+
+ return common_EncodeDerSig(dest, src);
+}
+
+/* src is a DER-encoded DSA signature.
+** Returns a newly-allocated SECItem structure, pointing at a newly allocated
+** buffer containing the "raw" DSA1 signature, which is 20 bytes of r,
+** followed by 20 bytes of s.
+*/
+SECItem *
+DSAU_DecodeDerSig(const SECItem *item)
+{
+ return common_DecodeDerSig(item, DSA1_SUBPRIME_LEN);
+}
+
+/* src is a DER-encoded ECDSA signature.
+** Returns a newly-allocated SECItem structure, pointing at a newly allocated
+** buffer containing the "raw" ECDSA signature of length len containing
+** r followed by s (both padded to take up exactly len/2 bytes).
+*/
+SECItem *
+DSAU_DecodeDerSigToLen(const SECItem *item, unsigned int len)
+{
+ return common_DecodeDerSig(item, len / 2);
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-27 15:15:50 +0000