+#else
+ int blocks, bsize, pcount, padsize;
+ unsigned int max_needed, ifraglen, ofraglen, output_len;
+ unsigned char *pbuf;
+ OSStatus rv;
+
+ PORT_Assert (! cc->encrypt);
+
+ /*
+ * Check that we have enough room for the output. Our caller should
+ * already handle this; failure is really an internal error (i.e. bug).
+ */
+ max_needed = SecCmsCipherContextDecryptLength(cc, input_len, final);
+ PORT_Assert (max_output_len >= max_needed);
+ if (max_output_len < max_needed) {
+ /* PORT_SetError (XXX); */
+ return SECFailure;
+ }
+
+ /*
+ * hardware encryption does not like small decryption sizes here, so we
+ * allow both blocking and padding.
+ */
+ bsize = cc->block_size;
+ padsize = cc->pad_size;
+
+ /*
+ * When no blocking or padding work to do, we can simply call the
+ * cipher function and we are done.
+ */
+ if (bsize == 0) {
+ return (* cc->doit) (cc->cx, output, output_len_p, max_output_len,
+ input, input_len);
+ }
+
+ pcount = cc->pending_count;
+ pbuf = cc->pending_buf;
+
+ output_len = 0;
+
+ if (pcount) {
+ /*
+ * Try to fill in an entire block, starting with the bytes
+ * we already have saved away.
+ */
+ while (input_len && pcount < bsize) {
+ pbuf[pcount++] = *input++;
+ input_len--;
+ }
+ /*
+ * If we have at most a whole block and this is not our last call,
+ * then we are done for now. (We do not try to decrypt a lone
+ * single block because we cannot interpret the padding bytes
+ * until we know we are handling the very last block of all input.)
+ */
+ if (input_len == 0 && !final) {
+ cc->pending_count = pcount;
+ if (output_len_p)
+ *output_len_p = 0;
+ return SECSuccess;
+ }
+ /*
+ * Given the logic above, we expect to have a full block by now.
+ * If we do not, there is something wrong, either with our own
+ * logic or with (length of) the data given to us.
+ */
+ if ((padsize != 0) && (pcount % padsize) != 0) {
+ PORT_Assert (final);
+ PORT_SetError (SEC_ERROR_BAD_DATA);
+ return SECFailure;
+ }
+ /*
+ * Decrypt the block.
+ */
+ rv = (*cc->doit)(cc->cx, output, &ofraglen, max_output_len,
+ pbuf, pcount);
+ if (rv != SECSuccess)
+ return rv;
+
+ /*
+ * For now anyway, all of our ciphers have the same number of
+ * bytes of output as they do input. If this ever becomes untrue,
+ * then SecCmsCipherContextDecryptLength needs to be made smarter!
+ */
+ PORT_Assert(ofraglen == pcount);
+
+ /*
+ * Account for the bytes now in output.
+ */
+ max_output_len -= ofraglen;
+ output_len += ofraglen;
+ output += ofraglen;
+ }
+
+ /*
+ * If this is our last call, we expect to have an exact number of
+ * blocks left to be decrypted; we will decrypt them all.
+ *
+ * If not our last call, we always save between 1 and bsize bytes
+ * until next time. (We must do this because we cannot be sure
+ * that none of the decrypted bytes are padding bytes until we
+ * have at least another whole block of data. You cannot tell by
+ * looking -- the data could be anything -- you can only tell by
+ * context, knowing you are looking at the last block.) We could
+ * decrypt a whole block now but it is easier if we just treat it
+ * the same way we treat partial block bytes.
+ */
+ if (final) {
+ if (padsize) {
+ blocks = input_len / padsize;
+ ifraglen = blocks * padsize;
+ } else ifraglen = input_len;
+ PORT_Assert (ifraglen == input_len);
+
+ if (ifraglen != input_len) {
+ PORT_SetError(SEC_ERROR_BAD_DATA);
+ return SECFailure;
+ }
+ } else {
+ blocks = (input_len - 1) / bsize;
+ ifraglen = blocks * bsize;
+ PORT_Assert (ifraglen < input_len);
+
+ pcount = input_len - ifraglen;
+ PORT_Memcpy (pbuf, input + ifraglen, pcount);
+ cc->pending_count = pcount;
+ }
+
+ if (ifraglen) {
+ rv = (* cc->doit)(cc->cx, output, &ofraglen, max_output_len,
+ input, ifraglen);
+ if (rv != SECSuccess)
+ return rv;
+
+ /*
+ * For now anyway, all of our ciphers have the same number of
+ * bytes of output as they do input. If this ever becomes untrue,
+ * then sec_PKCS7DecryptLength needs to be made smarter!
+ */
+ PORT_Assert (ifraglen == ofraglen);
+ if (ifraglen != ofraglen) {
+ PORT_SetError(SEC_ERROR_BAD_DATA);
+ return SECFailure;
+ }
+
+ output_len += ofraglen;
+ } else {
+ ofraglen = 0;
+ }
+
+ /*
+ * If we just did our very last block, "remove" the padding by
+ * adjusting the output length.
+ */
+ if (final && (padsize != 0)) {
+ unsigned int padlen = *(output + ofraglen - 1);
+
+ if (padlen == 0 || padlen > padsize) {
+ PORT_SetError(SEC_ERROR_BAD_DATA);
+ return SECFailure;
+ }
+ output_len -= padlen;
+ }
+
+ PORT_Assert (output_len_p != NULL || output_len == 0);
+ if (output_len_p != NULL)
+ *output_len_p = output_len;
+
+ return SECSuccess;
+#endif
projects / apple / security.git / blobdiff