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asn1parse: avoid double free

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|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)
This commit is contained in:
Richard Levitte 2019-04-15 13:15:55 +02:00
parent 87d9955e8c
commit 4f29f3a29b
1 changed files with 5 additions and 7 deletions
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12
apps/asn1pars.c
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@ -170,17 +170,17 @@ int asn1parse_main(int argc, char **argv)
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) {
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 = BUF_MEM_new()) == NULL)
goto end;
if (!BUF_MEM_grow(buf, BUFSIZ * 8))
goto end; /* Pre-allocate :-) */
@ -303,8 +303,6 @@ int asn1parse_main(int argc, char **argv)
BUF_MEM_free(buf);
OPENSSL_free(name);
OPENSSL_free(header);
if (strictpem)
OPENSSL_free(str);
ASN1_TYPE_free(at);
sk_OPENSSL_STRING_free(osk);
return ret;