From f34a57202be4a5d3786ba65ad88d760aa02630f0 Mon Sep 17 00:00:00 2001
From: Emilia Kasper <emilia@openssl.org>
Date: Mon, 25 Aug 2014 12:38:16 +0200
Subject: [PATCH] Explicitly check for empty ASN.1 strings in d2i_ECPrivateKey
The old code implicitly relies on the ASN.1 code returning a \0-prefixed buffer
when the buffer length is 0. Change this to verify explicitly that the ASN.1 string
has positive length.
Reviewed-by: Dr Stephen Henson <steve@openssl.org>
---
crypto/ec/ec_asn1.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/crypto/ec/ec_asn1.c b/crypto/ec/ec_asn1.c
index 26d6360454..52d31c2f96 100644
--- a/crypto/ec/ec_asn1.c
+++ b/crypto/ec/ec_asn1.c
@@ -1195,14 +1195,20 @@ EC_KEY *d2i_ECPrivateKey(EC_KEY **a, const unsigned char **in, long len)
if (priv_key->publicKey)
{
const unsigned char *pub_oct;
- size_t pub_oct_len;
+ int pub_oct_len;
pub_oct = M_ASN1_STRING_data(priv_key->publicKey);
pub_oct_len = M_ASN1_STRING_length(priv_key->publicKey);
- /* save the point conversion form */
+ /* The first byte - point conversion form - must be present. */
+ if (pub_oct_len <= 0)
+ {
+ ECerr(EC_F_D2I_ECPRIVATEKEY, EC_R_BUFFER_TOO_SMALL);
+ goto err;
+ }
+ /* Save the point conversion form. */
ret->conv_form = (point_conversion_form_t)(pub_oct[0] & ~0x01);
if (!EC_POINT_oct2point(ret->group, ret->pub_key,
- pub_oct, pub_oct_len, NULL))
+ pub_oct, (size_t)(pub_oct_len), NULL))
{
ECerr(EC_F_D2I_ECPRIVATEKEY, ERR_R_EC_LIB);
goto err;
--
2.25.1