Fix encoding bug in i2c_ASN1_INTEGER

Fix bug where i2c_ASN1_INTEGER mishandles zero if it is marked as
negative.

Thanks to Huzaifa Sidhpurwala <huzaifas@redhat.com> and
Hanno Böck <hanno@hboeck.de> for reporting this issue.

Reviewed-by: Rich Salz <rsalz@openssl.org>
(cherry picked from commit a0eed48d37)
This commit is contained in:
Dr. Stephen Henson 2015-04-16 16:43:09 +01:00
parent 31d085ca74
commit 32d3b0f52f

View file

@ -124,6 +124,8 @@ int i2c_ASN1_INTEGER(ASN1_INTEGER *a, unsigned char **pp)
else {
ret = a->length;
i = a->data[0];
if (ret == 1 && i == 0)
neg = 0;
if (!neg && (i > 127)) {
pad = 1;
pb = 0;
@ -162,7 +164,7 @@ int i2c_ASN1_INTEGER(ASN1_INTEGER *a, unsigned char **pp)
p += a->length - 1;
i = a->length;
/* Copy zeros to destination as long as source is zero */
while (!*n) {
while (!*n && i > 1) {
*(p--) = 0;
n--;
i--;
@ -419,7 +421,7 @@ ASN1_INTEGER *BN_to_ASN1_INTEGER(const BIGNUM *bn, ASN1_INTEGER *ai)
ASN1err(ASN1_F_BN_TO_ASN1_INTEGER, ERR_R_NESTED_ASN1_ERROR);
goto err;
}
if (BN_is_negative(bn))
if (BN_is_negative(bn) && !BN_is_zero(bn))
ret->type = V_ASN1_NEG_INTEGER;
else
ret->type = V_ASN1_INTEGER;