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openssl/apps/asn1pars.c
Richard Levitte 4f29f3a29b asn1parse: avoid double free 
|str| was used for multiple conflicting purposes.  When using
'-strictpem', it's used to uniquely hold a reference to the loaded
payload.  However, when using '-strparse', |str| was re-used to hold
the position from where to start parsing.

So when '-strparse' and '-strictpem' are were together, |str| ended up
pointing into data pointed at by |at|, and was yet being freed, with
the result that the payload it held a reference to became a memory
leak, and there was a double free conflict when both |str| and |at|
were being freed.

The situation is resolved by always having |buf| hold the pointer to
the file data, and always and only use |str| to hold the position to
start parsing from.  Now, we only need to free |buf| properly and not
|str|.

Fixes #8752

Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
(Merged from https://github.com/openssl/openssl/pull/8753)
2019-04-18 19:20:55 +02:00

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/*
* Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (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 <stdlib.h>
#include <string.h>
#include "apps.h"
#include "progs.h"
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/x509.h>
#include <openssl/pem.h>
#include <openssl/asn1t.h>
typedef enum OPTION_choice {
OPT_ERR = -1, OPT_EOF = 0, OPT_HELP,
OPT_INFORM, OPT_IN, OPT_OUT, OPT_INDENT, OPT_NOOUT,
OPT_OID, OPT_OFFSET, OPT_LENGTH, OPT_DUMP, OPT_DLIMIT,
OPT_STRPARSE, OPT_GENSTR, OPT_GENCONF, OPT_STRICTPEM,
OPT_ITEM
} OPTION_CHOICE;
const OPTIONS asn1parse_options[] = {
{"help", OPT_HELP, '-', "Display this summary"},
{"inform", OPT_INFORM, 'F', "input format - one of DER PEM"},
{"in", OPT_IN, '<', "input file"},
{"out", OPT_OUT, '>', "output file (output format is always DER)"},
{"i", OPT_INDENT, 0, "indents the output"},
{"noout", OPT_NOOUT, 0, "do not produce any output"},
{"offset", OPT_OFFSET, 'p', "offset into file"},
{"length", OPT_LENGTH, 'p', "length of section in file"},
{"oid", OPT_OID, '<', "file of extra oid definitions"},
{"dump", OPT_DUMP, 0, "unknown data in hex form"},
{"dlimit", OPT_DLIMIT, 'p',
"dump the first arg bytes of unknown data in hex form"},
{"strparse", OPT_STRPARSE, 'p',
"offset; a series of these can be used to 'dig'"},
{OPT_MORE_STR, 0, 0, "into multiple ASN1 blob wrappings"},
{"genstr", OPT_GENSTR, 's', "string to generate ASN1 structure from"},
{"genconf", OPT_GENCONF, 's', "file to generate ASN1 structure from"},
{OPT_MORE_STR, 0, 0, "(-inform will be ignored)"},
{"strictpem", OPT_STRICTPEM, 0,
"do not attempt base64 decode outside PEM markers"},
{"item", OPT_ITEM, 's', "item to parse and print"},
{NULL}
};
static int do_generate(char *genstr, const char *genconf, BUF_MEM *buf);
int asn1parse_main(int argc, char **argv)
{
ASN1_TYPE *at = NULL;
BIO *in = NULL, *b64 = NULL, *derout = NULL;
BUF_MEM *buf = NULL;
STACK_OF(OPENSSL_STRING) *osk = NULL;
char *genstr = NULL, *genconf = NULL;
char *infile = NULL, *oidfile = NULL, *derfile = NULL;
unsigned char *str = NULL;
char *name = NULL, *header = NULL, *prog;
const unsigned char *ctmpbuf;
int indent = 0, noout = 0, dump = 0, strictpem = 0, informat = FORMAT_PEM;
int offset = 0, ret = 1, i, j;
long num, tmplen;
unsigned char *tmpbuf;
unsigned int length = 0;
OPTION_CHOICE o;
const ASN1_ITEM *it = NULL;
prog = opt_init(argc, argv, asn1parse_options);
if ((osk = sk_OPENSSL_STRING_new_null()) == NULL) {
BIO_printf(bio_err, "%s: Memory allocation failure\n", prog);
goto end;
}
while ((o = opt_next()) != OPT_EOF) {
switch (o) {
case OPT_EOF:
case OPT_ERR:
opthelp:
BIO_printf(bio_err, "%s: Use -help for summary.\n", prog);
goto end;
case OPT_HELP:
opt_help(asn1parse_options);
ret = 0;
goto end;
case OPT_INFORM:
if (!opt_format(opt_arg(), OPT_FMT_PEMDER, &informat))
goto opthelp;
break;
case OPT_IN:
infile = opt_arg();
break;
case OPT_OUT:
derfile = opt_arg();
break;
case OPT_INDENT:
indent = 1;
break;
case OPT_NOOUT:
noout = 1;
break;
case OPT_OID:
oidfile = opt_arg();
break;
case OPT_OFFSET:
offset = strtol(opt_arg(), NULL, 0);
break;
case OPT_LENGTH:
length = strtol(opt_arg(), NULL, 0);
break;
case OPT_DUMP:
dump = -1;
break;
case OPT_DLIMIT:
dump = strtol(opt_arg(), NULL, 0);
break;
case OPT_STRPARSE:
sk_OPENSSL_STRING_push(osk, opt_arg());
break;
case OPT_GENSTR:
genstr = opt_arg();
break;
case OPT_GENCONF:
genconf = opt_arg();
break;
case OPT_STRICTPEM:
strictpem = 1;
informat = FORMAT_PEM;
break;
case OPT_ITEM:
it = ASN1_ITEM_lookup(opt_arg());
if (it == NULL) {
size_t tmp;
BIO_printf(bio_err, "Unknown item name %s\n", opt_arg());
BIO_puts(bio_err, "Supported types:\n");
for (tmp = 0;; tmp++) {
it = ASN1_ITEM_get(tmp);
if (it == NULL)
break;
BIO_printf(bio_err, " %s\n", it->sname);
}
goto end;
}
break;
}
}
argc = opt_num_rest();
if (argc != 0)
goto opthelp;
if (oidfile != NULL) {
in = bio_open_default(oidfile, 'r', FORMAT_TEXT);
if (in == NULL)
goto end;
OBJ_create_objects(in);
BIO_free(in);
}
if ((in = bio_open_default(infile, 'r', informat)) == NULL)
goto end;
if (derfile && (derout = bio_open_default(derfile, 'w', FORMAT_ASN1)) == NULL)
goto end;
if ((buf = BUF_MEM_new()) == NULL)
goto end;
if (strictpem) {
if (PEM_read_bio(in, &name, &header, &str, &num) != 1) {
BIO_printf(bio_err, "Error reading PEM file\n");
ERR_print_errors(bio_err);
goto end;
}
buf->data = (char *)str;
buf->length = buf->max = num;
} else {
if (!BUF_MEM_grow(buf, BUFSIZ * 8))
goto end; /* Pre-allocate :-) */
if (genstr || genconf) {
num = do_generate(genstr, genconf, buf);
if (num < 0) {
ERR_print_errors(bio_err);
goto end;
}
} else {
if (informat == FORMAT_PEM) {
BIO *tmp;
if ((b64 = BIO_new(BIO_f_base64())) == NULL)
goto end;
BIO_push(b64, in);
tmp = in;
in = b64;
b64 = tmp;
}
num = 0;
for (;;) {
if (!BUF_MEM_grow(buf, num + BUFSIZ))
goto end;
i = BIO_read(in, &(buf->data[num]), BUFSIZ);
if (i <= 0)
break;
num += i;
}
}
str = (unsigned char *)buf->data;
}
/* If any structs to parse go through in sequence */
if (sk_OPENSSL_STRING_num(osk)) {
tmpbuf = str;
tmplen = num;
for (i = 0; i < sk_OPENSSL_STRING_num(osk); i++) {
ASN1_TYPE *atmp;
int typ;
j = strtol(sk_OPENSSL_STRING_value(osk, i), NULL, 0);
if (j <= 0 || j >= tmplen) {
BIO_printf(bio_err, "'%s' is out of range\n",
sk_OPENSSL_STRING_value(osk, i));
continue;
}
tmpbuf += j;
tmplen -= j;
atmp = at;
ctmpbuf = tmpbuf;
at = d2i_ASN1_TYPE(NULL, &ctmpbuf, tmplen);
ASN1_TYPE_free(atmp);
if (!at) {
BIO_printf(bio_err, "Error parsing structure\n");
ERR_print_errors(bio_err);
goto end;
}
typ = ASN1_TYPE_get(at);
if ((typ == V_ASN1_OBJECT)
|| (typ == V_ASN1_BOOLEAN)
|| (typ == V_ASN1_NULL)) {
BIO_printf(bio_err, "Can't parse %s type\n", ASN1_tag2str(typ));
ERR_print_errors(bio_err);
goto end;
}
/* hmm... this is a little evil but it works */
tmpbuf = at->value.asn1_string->data;
tmplen = at->value.asn1_string->length;
}
str = tmpbuf;
num = tmplen;
}
if (offset < 0 || offset >= num) {
BIO_printf(bio_err, "Error: offset out of range\n");
goto end;
}
num -= offset;
if (length == 0 || length > (unsigned int)num)
length = (unsigned int)num;
if (derout != NULL) {
if (BIO_write(derout, str + offset, length) != (int)length) {
BIO_printf(bio_err, "Error writing output\n");
ERR_print_errors(bio_err);
goto end;
}
}
if (!noout) {
const unsigned char *p = str + offset;
if (it != NULL) {
ASN1_VALUE *value = ASN1_item_d2i(NULL, &p, length, it);
if (value == NULL) {
BIO_printf(bio_err, "Error parsing item %s\n", it->sname);
ERR_print_errors(bio_err);
goto end;
}
ASN1_item_print(bio_out, value, 0, it, NULL);
ASN1_item_free(value, it);
} else {
if (!ASN1_parse_dump(bio_out, p, length, indent, dump)) {
ERR_print_errors(bio_err);
goto end;
}
}
}
ret = 0;
end:
BIO_free(derout);
BIO_free(in);
BIO_free(b64);
if (ret != 0)
ERR_print_errors(bio_err);
BUF_MEM_free(buf);
OPENSSL_free(name);
OPENSSL_free(header);
ASN1_TYPE_free(at);
sk_OPENSSL_STRING_free(osk);
return ret;
}
static int do_generate(char *genstr, const char *genconf, BUF_MEM *buf)
{
CONF *cnf = NULL;
int len;
unsigned char *p;
ASN1_TYPE *atyp = NULL;
if (genconf != NULL) {
if ((cnf = app_load_config(genconf)) == NULL)
goto err;
if (genstr == NULL)
genstr = NCONF_get_string(cnf, "default", "asn1");
if (genstr == NULL) {
BIO_printf(bio_err, "Can't find 'asn1' in '%s'\n", genconf);
goto err;
}
}
atyp = ASN1_generate_nconf(genstr, cnf);
NCONF_free(cnf);
cnf = NULL;
if (atyp == NULL)
return -1;
len = i2d_ASN1_TYPE(atyp, NULL);
if (len <= 0)
goto err;
if (!BUF_MEM_grow(buf, len))
goto err;
p = (unsigned char *)buf->data;
i2d_ASN1_TYPE(atyp, &p);
ASN1_TYPE_free(atyp);
return len;
err:
NCONF_free(cnf);
ASN1_TYPE_free(atyp);
return -1;
}
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