--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/nss/lib/util/dersubr.c	Mon Jul 28 10:47:06 2014 +0200
@@ -0,0 +1,246 @@
+/* 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 "secder.h"
+#include <limits.h>
+#include "secerr.h"
+
+int
+DER_LengthLength(PRUint32 len)
+{
+    if (len > 127) {
+	if (len > 255) {
+	    if (len > 65535L) {
+		if (len > 16777215L) {
+		    return 5;
+		} else {
+		    return 4;
+		}
+	    } else {
+		return 3;
+	    }
+	} else {
+	    return 2;
+	}
+    } else {
+	return 1;
+    }
+}
+
+unsigned char *
+DER_StoreHeader(unsigned char *buf, unsigned int code, PRUint32 len)
+{
+    unsigned char b[4];
+
+    b[0] = (unsigned char)(len >> 24);
+    b[1] = (unsigned char)(len >> 16);
+    b[2] = (unsigned char)(len >> 8);
+    b[3] = (unsigned char)len;
+    if ((code & DER_TAGNUM_MASK) == DER_SET
+	|| (code & DER_TAGNUM_MASK) == DER_SEQUENCE)
+	code |= DER_CONSTRUCTED;
+    *buf++ = code;
+    if (len > 127) {
+	if (len > 255) {
+	    if (len > 65535) {
+		if (len > 16777215) {
+		    *buf++ = 0x84;
+		    *buf++ = b[0];
+		    *buf++ = b[1];
+		    *buf++ = b[2];
+		    *buf++ = b[3];
+		} else {
+		    *buf++ = 0x83;
+		    *buf++ = b[1];
+		    *buf++ = b[2];
+		    *buf++ = b[3];
+		}
+	    } else {
+		*buf++ = 0x82;
+		*buf++ = b[2];
+		*buf++ = b[3];
+	    }
+	} else {
+	    *buf++ = 0x81;
+	    *buf++ = b[3];
+	}
+    } else {
+	*buf++ = b[3];
+    }
+    return buf;
+}
+
+/*
+ * XXX This should be rewritten, generalized, to take a long instead
+ * of a PRInt32.
+ */
+SECStatus
+DER_SetInteger(PLArenaPool *arena, SECItem *it, PRInt32 i)
+{
+    unsigned char bb[4];
+    unsigned len;
+
+    bb[0] = (unsigned char) (i >> 24);
+    bb[1] = (unsigned char) (i >> 16);
+    bb[2] = (unsigned char) (i >> 8);
+    bb[3] = (unsigned char) (i);
+
+    /*
+    ** Small integers are encoded in a single byte. Larger integers
+    ** require progressively more space.
+    */
+    if (i < -128) {
+	if (i < -32768L) {
+	    if (i < -8388608L) {
+		len = 4;
+	    } else {
+		len = 3;
+	    }
+	} else {
+	    len = 2;
+	}
+    } else if (i > 127) {
+	if (i > 32767L) {
+	    if (i > 8388607L) {
+		len = 4;
+	    } else {
+		len = 3;
+	    }
+	} else {
+	    len = 2;
+	}
+    } else {
+	len = 1;
+    }
+    it->data = (unsigned char*) PORT_ArenaAlloc(arena, len);
+    if (!it->data) {
+	return SECFailure;
+    }
+    it->len = len;
+    PORT_Memcpy(it->data, bb + (4 - len), len);
+    return SECSuccess;
+}
+
+/*
+ * XXX This should be rewritten, generalized, to take an unsigned long instead
+ * of a PRUint32.
+ */
+SECStatus
+DER_SetUInteger(PLArenaPool *arena, SECItem *it, PRUint32 ui)
+{
+    unsigned char bb[5];
+    int len;
+
+    bb[0] = 0;
+    bb[1] = (unsigned char) (ui >> 24);
+    bb[2] = (unsigned char) (ui >> 16);
+    bb[3] = (unsigned char) (ui >> 8);
+    bb[4] = (unsigned char) (ui);
+
+    /*
+    ** Small integers are encoded in a single byte. Larger integers
+    ** require progressively more space.
+    */
+    if (ui > 0x7f) {
+	if (ui > 0x7fff) {
+	    if (ui > 0x7fffffL) {
+		if (ui >= 0x80000000L) {
+		    len = 5;
+		} else {
+		    len = 4;
+		}
+	    } else {
+		len = 3;
+	    }
+	} else {
+	    len = 2;
+	}
+    } else {
+	len = 1;
+    }
+
+    it->data = (unsigned char *)PORT_ArenaAlloc(arena, len);
+    if (it->data == NULL) {
+	return SECFailure;
+    }
+
+    it->len = len;
+    PORT_Memcpy(it->data, bb + (sizeof(bb) - len), len);
+
+    return SECSuccess;
+}
+
+/*
+** Convert a der encoded *signed* integer into a machine integral value.
+** If an underflow/overflow occurs, sets error code and returns min/max.
+*/
+long
+DER_GetInteger(const SECItem *it)
+{
+    long ival = 0;
+    unsigned len = it->len;
+    unsigned char *cp = it->data;
+    unsigned long overflow = 0x1ffUL << (((sizeof(ival) - 1) * 8) - 1);
+    unsigned long ofloinit;
+
+    PORT_Assert(len);
+    if (!len) {
+	PORT_SetError(SEC_ERROR_INPUT_LEN);
+	return 0;
+    }
+
+    if (*cp & 0x80)
+    	ival = -1L;
+    ofloinit = ival & overflow;
+
+    while (len) {
+	if ((ival & overflow) != ofloinit) {
+	    PORT_SetError(SEC_ERROR_BAD_DER);
+	    if (ival < 0) {
+		return LONG_MIN;
+	    }
+	    return LONG_MAX;
+	}
+	ival = ival << 8;
+	ival |= *cp++;
+	--len;
+    }
+    return ival;
+}
+
+/*
+** Convert a der encoded *unsigned* integer into a machine integral value.
+** If an overflow occurs, sets error code and returns max.
+*/
+unsigned long
+DER_GetUInteger(SECItem *it)
+{
+    unsigned long ival = 0;
+    unsigned len = it->len;
+    unsigned char *cp = it->data;
+    unsigned long overflow = 0xffUL << ((sizeof(ival) - 1) * 8);
+
+    PORT_Assert(len);
+    if (!len) {
+	PORT_SetError(SEC_ERROR_INPUT_LEN);
+	return 0;
+    }
+
+    /* Cannot put a negative value into an unsigned container. */
+    if (*cp & 0x80) {
+	PORT_SetError(SEC_ERROR_BAD_DER);
+	return 0;
+    }
+
+    while (len) {
+	if (ival & overflow) {
+	    PORT_SetError(SEC_ERROR_BAD_DER);
+	    return ULONG_MAX;
+	}
+	ival = ival << 8;
+	ival |= *cp++;
+	--len;
+    }
+    return ival;
+}