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1258a8e436
The negative integer check is done to prevent potential overflow. Fixes #20719. CLA: trivial Reviewed-by: Tomas Mraz <tomas@openssl.org> Reviewed-by: Paul Dale <pauli@openssl.org> (Merged from https://github.com/openssl/openssl/pull/20862)
218 lines
5.2 KiB
C
218 lines
5.2 KiB
C
/*
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* Copyright 1995-2021 The OpenSSL Project Authors. All Rights Reserved.
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*
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* Licensed under the Apache License 2.0 (the "License"). You may not use
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* this file except in compliance with the License. You can obtain a copy
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* in the file LICENSE in the source distribution or at
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* https://www.openssl.org/source/license.html
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*/
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#include <limits.h>
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#include <stdio.h>
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#include "internal/cryptlib.h"
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#include <openssl/asn1.h>
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#include "asn1_local.h"
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int ASN1_BIT_STRING_set(ASN1_BIT_STRING *x, unsigned char *d, int len)
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{
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return ASN1_STRING_set(x, d, len);
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}
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int ossl_i2c_ASN1_BIT_STRING(ASN1_BIT_STRING *a, unsigned char **pp)
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{
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int ret, j, bits, len;
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unsigned char *p, *d;
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if (a == NULL)
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return 0;
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len = a->length;
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if (len > 0) {
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if (a->flags & ASN1_STRING_FLAG_BITS_LEFT) {
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bits = (int)a->flags & 0x07;
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} else {
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for (; len > 0; len--) {
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if (a->data[len - 1])
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break;
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}
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j = a->data[len - 1];
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if (j & 0x01)
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bits = 0;
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else if (j & 0x02)
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bits = 1;
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else if (j & 0x04)
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bits = 2;
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else if (j & 0x08)
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bits = 3;
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else if (j & 0x10)
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bits = 4;
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else if (j & 0x20)
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bits = 5;
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else if (j & 0x40)
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bits = 6;
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else if (j & 0x80)
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bits = 7;
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else
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bits = 0; /* should not happen */
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}
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} else
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bits = 0;
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ret = 1 + len;
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if (pp == NULL)
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return ret;
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p = *pp;
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*(p++) = (unsigned char)bits;
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d = a->data;
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if (len > 0) {
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memcpy(p, d, len);
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p += len;
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p[-1] &= (0xff << bits);
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}
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*pp = p;
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return ret;
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}
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ASN1_BIT_STRING *ossl_c2i_ASN1_BIT_STRING(ASN1_BIT_STRING **a,
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const unsigned char **pp, long len)
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{
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ASN1_BIT_STRING *ret = NULL;
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const unsigned char *p;
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unsigned char *s;
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int i = 0;
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if (len < 1) {
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i = ASN1_R_STRING_TOO_SHORT;
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goto err;
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}
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if (len > INT_MAX) {
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i = ASN1_R_STRING_TOO_LONG;
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goto err;
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}
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if ((a == NULL) || ((*a) == NULL)) {
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if ((ret = ASN1_BIT_STRING_new()) == NULL)
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return NULL;
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} else
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ret = (*a);
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p = *pp;
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i = *(p++);
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if (i > 7) {
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i = ASN1_R_INVALID_BIT_STRING_BITS_LEFT;
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goto err;
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}
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/*
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* We do this to preserve the settings. If we modify the settings, via
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* the _set_bit function, we will recalculate on output
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*/
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ossl_asn1_string_set_bits_left(ret, i);
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if (len-- > 1) { /* using one because of the bits left byte */
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s = OPENSSL_malloc((int)len);
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if (s == NULL) {
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goto err;
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}
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memcpy(s, p, (int)len);
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s[len - 1] &= (0xff << i);
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p += len;
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} else
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s = NULL;
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ASN1_STRING_set0(ret, s, (int)len);
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ret->type = V_ASN1_BIT_STRING;
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if (a != NULL)
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(*a) = ret;
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*pp = p;
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return ret;
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err:
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if (i != 0)
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ERR_raise(ERR_LIB_ASN1, i);
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if ((a == NULL) || (*a != ret))
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ASN1_BIT_STRING_free(ret);
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return NULL;
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}
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/*
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* These next 2 functions from Goetz Babin-Ebell.
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*/
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int ASN1_BIT_STRING_set_bit(ASN1_BIT_STRING *a, int n, int value)
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{
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int w, v, iv;
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unsigned char *c;
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if (n < 0)
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return 0;
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w = n / 8;
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v = 1 << (7 - (n & 0x07));
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iv = ~v;
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if (!value)
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v = 0;
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if (a == NULL)
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return 0;
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a->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07); /* clear, set on write */
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if ((a->length < (w + 1)) || (a->data == NULL)) {
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if (!value)
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return 1; /* Don't need to set */
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c = OPENSSL_clear_realloc(a->data, a->length, w + 1);
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if (c == NULL)
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return 0;
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if (w + 1 - a->length > 0)
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memset(c + a->length, 0, w + 1 - a->length);
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a->data = c;
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a->length = w + 1;
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}
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a->data[w] = ((a->data[w]) & iv) | v;
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while ((a->length > 0) && (a->data[a->length - 1] == 0))
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a->length--;
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return 1;
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}
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int ASN1_BIT_STRING_get_bit(const ASN1_BIT_STRING *a, int n)
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{
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int w, v;
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if (n < 0)
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return 0;
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w = n / 8;
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v = 1 << (7 - (n & 0x07));
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if ((a == NULL) || (a->length < (w + 1)) || (a->data == NULL))
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return 0;
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return ((a->data[w] & v) != 0);
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}
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/*
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* Checks if the given bit string contains only bits specified by
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* the flags vector. Returns 0 if there is at least one bit set in 'a'
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* which is not specified in 'flags', 1 otherwise.
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* 'len' is the length of 'flags'.
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*/
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int ASN1_BIT_STRING_check(const ASN1_BIT_STRING *a,
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const unsigned char *flags, int flags_len)
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{
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int i, ok;
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/* Check if there is one bit set at all. */
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if (!a || !a->data)
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return 1;
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/*
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* Check each byte of the internal representation of the bit string.
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*/
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ok = 1;
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for (i = 0; i < a->length && ok; ++i) {
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unsigned char mask = i < flags_len ? ~flags[i] : 0xff;
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/* We are done if there is an unneeded bit set. */
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ok = (a->data[i] & mask) == 0;
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}
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return ok;
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}
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