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openssl/crypto/asn1/a_mbstr.c
Pauli 60eba30f60 Memory bounds checking in asn1 code. 
Check that sprint, strcpy don't overflow.

Avoid some strlen operations when the previous sprintf return value can be used.

Also fix the undefined behaviour `*(long *)x = y` when x isn't a long or character pointer.
ISO/IEC 9899:1999 6.5/7 for the details.

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3869)
2017-07-06 12:59:51 +10:00

395 lines
11 KiB
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/*
* Copyright 1999-2017 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include <stdio.h>
#include <ctype.h>
#include "internal/cryptlib.h"
#include <openssl/asn1.h>
static int traverse_string(const unsigned char *p, int len, int inform,
int (*rfunc) (unsigned long value, void *in),
void *arg);
static int in_utf8(unsigned long value, void *arg);
static int out_utf8(unsigned long value, void *arg);
static int type_str(unsigned long value, void *arg);
static int cpy_asc(unsigned long value, void *arg);
static int cpy_bmp(unsigned long value, void *arg);
static int cpy_univ(unsigned long value, void *arg);
static int cpy_utf8(unsigned long value, void *arg);
static int is_numeric(unsigned long value);
static int is_printable(unsigned long value);
/*
* These functions take a string in UTF8, ASCII or multibyte form and a mask
* of permissible ASN1 string types. It then works out the minimal type
* (using the order Numeric < Printable < IA5 < T61 < BMP < Universal < UTF8)
* and creates a string of the correct type with the supplied data. Yes this is
* horrible: it has to be :-( The 'ncopy' form checks minimum and maximum
* size limits too.
*/
int ASN1_mbstring_copy(ASN1_STRING **out, const unsigned char *in, int len,
int inform, unsigned long mask)
{
return ASN1_mbstring_ncopy(out, in, len, inform, mask, 0, 0);
}
int ASN1_mbstring_ncopy(ASN1_STRING **out, const unsigned char *in, int len,
int inform, unsigned long mask,
long minsize, long maxsize)
{
int str_type;
int ret;
char free_out;
int outform, outlen = 0;
ASN1_STRING *dest;
unsigned char *p;
int nchar;
char strbuf[32];
int (*cpyfunc) (unsigned long, void *) = NULL;
if (len == -1)
len = strlen((const char *)in);
if (!mask)
mask = DIRSTRING_TYPE;
/* First do a string check and work out the number of characters */
switch (inform) {
case MBSTRING_BMP:
if (len & 1) {
ASN1err(ASN1_F_ASN1_MBSTRING_NCOPY,
ASN1_R_INVALID_BMPSTRING_LENGTH);
return -1;
}
nchar = len >> 1;
break;
case MBSTRING_UNIV:
if (len & 3) {
ASN1err(ASN1_F_ASN1_MBSTRING_NCOPY,
ASN1_R_INVALID_UNIVERSALSTRING_LENGTH);
return -1;
}
nchar = len >> 2;
break;
case MBSTRING_UTF8:
nchar = 0;
/* This counts the characters and does utf8 syntax checking */
ret = traverse_string(in, len, MBSTRING_UTF8, in_utf8, &nchar);
if (ret < 0) {
ASN1err(ASN1_F_ASN1_MBSTRING_NCOPY, ASN1_R_INVALID_UTF8STRING);
return -1;
}
break;
case MBSTRING_ASC:
nchar = len;
break;
default:
ASN1err(ASN1_F_ASN1_MBSTRING_NCOPY, ASN1_R_UNKNOWN_FORMAT);
return -1;
}
if ((minsize > 0) && (nchar < minsize)) {
ASN1err(ASN1_F_ASN1_MBSTRING_NCOPY, ASN1_R_STRING_TOO_SHORT);
BIO_snprintf(strbuf, sizeof(strbuf), "%ld", minsize);
ERR_add_error_data(2, "minsize=", strbuf);
return -1;
}
if ((maxsize > 0) && (nchar > maxsize)) {
ASN1err(ASN1_F_ASN1_MBSTRING_NCOPY, ASN1_R_STRING_TOO_LONG);
BIO_snprintf(strbuf, sizeof(strbuf), "%ld", maxsize);
ERR_add_error_data(2, "maxsize=", strbuf);
return -1;
}
/* Now work out minimal type (if any) */
if (traverse_string(in, len, inform, type_str, &mask) < 0) {
ASN1err(ASN1_F_ASN1_MBSTRING_NCOPY, ASN1_R_ILLEGAL_CHARACTERS);
return -1;
}
/* Now work out output format and string type */
outform = MBSTRING_ASC;
if (mask & B_ASN1_NUMERICSTRING)
str_type = V_ASN1_NUMERICSTRING;
else if (mask & B_ASN1_PRINTABLESTRING)
str_type = V_ASN1_PRINTABLESTRING;
else if (mask & B_ASN1_IA5STRING)
str_type = V_ASN1_IA5STRING;
else if (mask & B_ASN1_T61STRING)
str_type = V_ASN1_T61STRING;
else if (mask & B_ASN1_BMPSTRING) {
str_type = V_ASN1_BMPSTRING;
outform = MBSTRING_BMP;
} else if (mask & B_ASN1_UNIVERSALSTRING) {
str_type = V_ASN1_UNIVERSALSTRING;
outform = MBSTRING_UNIV;
} else {
str_type = V_ASN1_UTF8STRING;
outform = MBSTRING_UTF8;
}
if (!out)
return str_type;
if (*out) {
free_out = 0;
dest = *out;
OPENSSL_free(dest->data);
dest->data = NULL;
dest->length = 0;
dest->type = str_type;
} else {
free_out = 1;
dest = ASN1_STRING_type_new(str_type);
if (dest == NULL) {
ASN1err(ASN1_F_ASN1_MBSTRING_NCOPY, ERR_R_MALLOC_FAILURE);
return -1;
}
*out = dest;
}
/* If both the same type just copy across */
if (inform == outform) {
if (!ASN1_STRING_set(dest, in, len)) {
ASN1err(ASN1_F_ASN1_MBSTRING_NCOPY, ERR_R_MALLOC_FAILURE);
return -1;
}
return str_type;
}
/* Work out how much space the destination will need */
switch (outform) {
case MBSTRING_ASC:
outlen = nchar;
cpyfunc = cpy_asc;
break;
case MBSTRING_BMP:
outlen = nchar << 1;
cpyfunc = cpy_bmp;
break;
case MBSTRING_UNIV:
outlen = nchar << 2;
cpyfunc = cpy_univ;
break;
case MBSTRING_UTF8:
outlen = 0;
traverse_string(in, len, inform, out_utf8, &outlen);
cpyfunc = cpy_utf8;
break;
}
if ((p = OPENSSL_malloc(outlen + 1)) == NULL) {
if (free_out)
ASN1_STRING_free(dest);
ASN1err(ASN1_F_ASN1_MBSTRING_NCOPY, ERR_R_MALLOC_FAILURE);
return -1;
}
dest->length = outlen;
dest->data = p;
p[outlen] = 0;
traverse_string(in, len, inform, cpyfunc, &p);
return str_type;
}
/*
* This function traverses a string and passes the value of each character to
* an optional function along with a void * argument.
*/
static int traverse_string(const unsigned char *p, int len, int inform,
int (*rfunc) (unsigned long value, void *in),
void *arg)
{
unsigned long value;
int ret;
while (len) {
if (inform == MBSTRING_ASC) {
value = *p++;
len--;
} else if (inform == MBSTRING_BMP) {
value = *p++ << 8;
value |= *p++;
len -= 2;
} else if (inform == MBSTRING_UNIV) {
value = ((unsigned long)*p++) << 24;
value |= ((unsigned long)*p++) << 16;
value |= *p++ << 8;
value |= *p++;
len -= 4;
} else {
ret = UTF8_getc(p, len, &value);
if (ret < 0)
return -1;
len -= ret;
p += ret;
}
if (rfunc) {
ret = rfunc(value, arg);
if (ret <= 0)
return ret;
}
}
return 1;
}
/* Various utility functions for traverse_string */
/* Just count number of characters */
static int in_utf8(unsigned long value, void *arg)
{
int *nchar;
nchar = arg;
(*nchar)++;
return 1;
}
/* Determine size of output as a UTF8 String */
static int out_utf8(unsigned long value, void *arg)
{
int *outlen;
outlen = arg;
*outlen += UTF8_putc(NULL, -1, value);
return 1;
}
/*
* Determine the "type" of a string: check each character against a supplied
* "mask".
*/
static int type_str(unsigned long value, void *arg)
{
unsigned long types;
types = *((unsigned long *)arg);
if ((types & B_ASN1_NUMERICSTRING) && !is_numeric(value))
types &= ~B_ASN1_NUMERICSTRING;
if ((types & B_ASN1_PRINTABLESTRING) && !is_printable(value))
types &= ~B_ASN1_PRINTABLESTRING;
if ((types & B_ASN1_IA5STRING) && (value > 127))
types &= ~B_ASN1_IA5STRING;
if ((types & B_ASN1_T61STRING) && (value > 0xff))
types &= ~B_ASN1_T61STRING;
if ((types & B_ASN1_BMPSTRING) && (value > 0xffff))
types &= ~B_ASN1_BMPSTRING;
if (!types)
return -1;
*((unsigned long *)arg) = types;
return 1;
}
/* Copy one byte per character ASCII like strings */
static int cpy_asc(unsigned long value, void *arg)
{
unsigned char **p, *q;
p = arg;
q = *p;
*q = (unsigned char)value;
(*p)++;
return 1;
}
/* Copy two byte per character BMPStrings */
static int cpy_bmp(unsigned long value, void *arg)
{
unsigned char **p, *q;
p = arg;
q = *p;
*q++ = (unsigned char)((value >> 8) & 0xff);
*q = (unsigned char)(value & 0xff);
*p += 2;
return 1;
}
/* Copy four byte per character UniversalStrings */
static int cpy_univ(unsigned long value, void *arg)
{
unsigned char **p, *q;
p = arg;
q = *p;
*q++ = (unsigned char)((value >> 24) & 0xff);
*q++ = (unsigned char)((value >> 16) & 0xff);
*q++ = (unsigned char)((value >> 8) & 0xff);
*q = (unsigned char)(value & 0xff);
*p += 4;
return 1;
}
/* Copy to a UTF8String */
static int cpy_utf8(unsigned long value, void *arg)
{
unsigned char **p;
int ret;
p = arg;
/* We already know there is enough room so pass 0xff as the length */
ret = UTF8_putc(*p, 0xff, value);
*p += ret;
return 1;
}
/* Return 1 if the character is permitted in a PrintableString */
static int is_printable(unsigned long value)
{
int ch;
if (value > 0x7f)
return 0;
ch = (int)value;
/*
* Note: we can't use 'isalnum' because certain accented characters may
* count as alphanumeric in some environments.
*/
#ifndef CHARSET_EBCDIC
if ((ch >= 'a') && (ch <= 'z'))
return 1;
if ((ch >= 'A') && (ch <= 'Z'))
return 1;
if ((ch >= '0') && (ch <= '9'))
return 1;
if ((ch == ' ') || strchr("'()+,-./:=?", ch))
return 1;
#else /* CHARSET_EBCDIC */
if ((ch >= os_toascii['a']) && (ch <= os_toascii['z']))
return 1;
if ((ch >= os_toascii['A']) && (ch <= os_toascii['Z']))
return 1;
if ((ch >= os_toascii['0']) && (ch <= os_toascii['9']))
return 1;
if ((ch == os_toascii[' ']) || strchr("'()+,-./:=?", os_toebcdic[ch]))
return 1;
#endif /* CHARSET_EBCDIC */
return 0;
}
/* Return 1 if the character is a digit or space */
static int is_numeric(unsigned long value)
{
int ch;
if (value > 0x7f)
return 0;
ch = (int)value;
#ifndef CHARSET_EBCDIC
if (!isdigit(ch) && ch != ' ')
return 0;
#else
if (ch > os_toascii['9'])
return 0;
if (ch < os_toascii['0'] && ch != os_toascii[' '])
return 0;
#endif
return 1;
}
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