Fix seg fault in ASN1_generate_v3/ASN1_generate_nconf

Reviewed-by: Dr. Stephen Henson <steve@openssl.org>
(cherry picked from commit ac5a110621ca48f0bebd5b4d76d081de403da29e)

diff --git a/crypto/asn1/asn1_gen.c b/crypto/asn1/asn1_gen.c
index b71ae4841b4941decc6986bbb2b2067303c2e3dd..11b582dd3744c305be2c7de8e58dd474b89eaa27 100644 (file)
--- a/crypto/asn1/asn1_gen.c
+++ b/crypto/asn1/asn1_gen.c
@@ -353,6 +353,10 @@ static int asn1_cb(const char *elem, int len, void *bitstr)
         break;
 
     case ASN1_GEN_FLAG_FORMAT:
+        if(!vstart) {
+            ASN1err(ASN1_F_ASN1_CB, ASN1_R_UNKNOWN_FORMAT);
+            return -1;
+        }
         if (!strncmp(vstart, "ASCII", 5))
             arg->format = ASN1_GEN_FORMAT_ASCII;
         else if (!strncmp(vstart, "UTF8", 4))