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 a0eed48d37a4b7beea0c966caf09ad46f4a92a44)
Bug: 28175332
Change-Id: I4366a15dee46a02e67746fd1642f2a7bd17f8f84
diff --git a/crypto/asn1/a_int.c b/crypto/asn1/a_int.c
index 297c45a..5374707 100644
--- a/crypto/asn1/a_int.c
+++ b/crypto/asn1/a_int.c
@@ -124,6 +124,8 @@
{
ret=a->length;
i=a->data[0];
+ if (ret == 1 && i == 0)
+ neg = 0;
if (!neg && (i > 127)) {
pad=1;
pb=0;
@@ -157,7 +159,7 @@
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--;
@@ -415,7 +417,7 @@
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;
j=BN_num_bits(bn);
diff --git a/patches/0020-encoding_neg_int.patch b/patches/0020-encoding_neg_int.patch
new file mode 100644
index 0000000..d475801
--- /dev/null
+++ b/patches/0020-encoding_neg_int.patch
@@ -0,0 +1,50 @@
+From: "Dr. Stephen Henson" <steve@openssl.org>
+Date: Thu, 16 Apr 2015 16:43:09 +0100
+Subject: [PATCH] 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>
+
+---
+ crypto/asn1/a_int.c | 6 ++++--
+ 1 file changed, 4 insertions(+), 2 deletions(-)
+
+diff --git a/crypto/asn1/a_int.c b/crypto/asn1/a_int.c
+index ad0d250..6574260 100644
+--- a/crypto/asn1/a_int.c
++++ b/crypto/asn1/a_int.c
+@@ -124,6 +124,8 @@ int i2c_ASN1_INTEGER(ASN1_INTEGER *a, unsigned char **pp)
+ {
+ ret=a->length;
+ i=a->data[0];
++ if (ret == 1 && i == 0)
++ neg = 0;
+ if (!neg && (i > 127)) {
+ pad=1;
+ pb=0;
+@@ -157,7 +159,7 @@ 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--;
+@@ -415,7 +417,7 @@ 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;
+ j=BN_num_bits(bn);
+--
+2.8.0.rc3.226.g39d4020
+
