import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

security/nss/lib/util/dersubr.c

@@ -0,0 +1,249 @@
+/* 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)
+{
+    unsigned long ival;
+    PRBool negative;
+    unsigned int len = it->len;
+    unsigned char *cp = it->data;
+    size_t lsize = sizeof(ival);
+
+    PORT_Assert(len);
+    if (!len) {
+        PORT_SetError(SEC_ERROR_INPUT_LEN);
+        return 0;
+    }
+
+    negative = (PRBool)(*cp & 0x80);
+    ival = negative ? ~0 : 0;
+
+    /* Ignore leading zeros/ones. */
+    while (len && *cp == (unsigned char)ival) {
+        len--;
+        cp++;
+    }
+
+    /* Check for overflow/underflow. */
+    if (len > lsize || (len == lsize && (*cp & 0x80) != negative)) {
+        PORT_SetError(SEC_ERROR_BAD_DER);
+        return negative ? LONG_MIN : LONG_MAX;
+    }
+
+    while (len--) {
+        ival <<= 8;
+        ival |= *cp++;
+    }
+
+    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;
+}