Set X509_V_ERR_INVALID_EXTENSION error for invalid basic constraints

If we encounter certificate with basic constraints CA:false,
pathlen present and X509_V_FLAG_X509_STRICT is set we set
X509_V_ERR_INVALID_EXTENSION error.

Reviewed-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Reviewed-by: Viktor Dukhovni <viktor@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/11463)

(cherry picked from commit fa86e2ee3533bb7fa9f3c62c38920cf960e9fec0)

diff --git a/crypto/x509/x509_vfy.c b/crypto/x509/x509_vfy.c
index f28f2d2610f6db48ca7165aec1526a935446f24f..41625e75ad6a6528357a065bc1fa96a1e421b97c 100644 (file)
--- a/crypto/x509/x509_vfy.c
+++ b/crypto/x509/x509_vfy.c
@@ -508,6 +508,12 @@ static int check_chain_extensions(X509_STORE_CTX *ctx)
                 ret = 1;
             break;
         }
+        if ((x->ex_flags & EXFLAG_CA) == 0
+            && x->ex_pathlen != -1
+            && (ctx->param->flags & X509_V_FLAG_X509_STRICT)) {
+            ctx->error = X509_V_ERR_INVALID_EXTENSION;
+            ret = 0;
+        }
         if (ret == 0 && !verify_cb_cert(ctx, x, i, X509_V_OK))
             return 0;
         /* check_purpose() makes the callback as needed */