| Message ID | 20150716165437.GA6590@salvia |
|---|---|
| State | Accepted |
| Delegated to: | Pablo Neira |
| Headers | show |
Pablo Neira Ayuso <pablo@netfilter.org> wrote: > On Thu, Jul 16, 2015 at 06:54:05PM +0200, Pablo Neira Ayuso wrote: > > On Thu, Jul 16, 2015 at 03:39:29PM +0200, Florian Westphal wrote: > > > Hi Pablo > > > > > > 09565a4b1ed4863d44c4509a93c50f44efd12771 > > > (netlink_delinearize: consolidate range printing) causes nft > > > to segfault on 32bit machine when printing l4proto ranges. > > > > > > The problem is that meta_expr_pctx_update() assumes that > > > right is a value, but after this change it can also be a value. > > > > > > Thus, expr->value contents are undefined (its union). > > > On x86_64 this is also broken but by virtue of struct layout > > > and pointer sizes, value->_mp_size will almost always be 0 > > > so mpz_get_uint8() returns 0. > > > > > > But on x86-32 _mp_size will be huge value (contains expr->right pointer > > > of range), so we crash in libgmp. > > > > Good catch. Could you give a try to this patch instead? > > > > We shouldn't call pctx_update(), before the transformation we had > > there a expr->op == { OP_GT, OP_GTE, OP_LT, OP_LTE }. So we never > > entered that path as the assert in payload_expr_pctx_update() > > indicates. > > Forgot patch, here it comes. > diff --git a/src/netlink_delinearize.c b/src/netlink_delinearize.c > index 6d60be3..4226b82 100644 > --- a/src/netlink_delinearize.c > +++ b/src/netlink_delinearize.c > @@ -983,6 +983,9 @@ static void meta_match_postprocess(struct rule_pp_ctx *ctx, > > switch (expr->op) { > case OP_EQ: > + if (expr->right->ops->type == EXPR_RANGE) > + break; > + > expr->left->ops->pctx_update(&ctx->pctx, expr); > Right thats better -- and it also avoids the crash. nft testsuite now passes with a few warnings and no crashes. Thanks! -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/src/netlink_delinearize.c b/src/netlink_delinearize.c index 6d60be3..4226b82 100644 --- a/src/netlink_delinearize.c +++ b/src/netlink_delinearize.c @@ -983,6 +983,9 @@ static void meta_match_postprocess(struct rule_pp_ctx *ctx, switch (expr->op) { case OP_EQ: + if (expr->right->ops->type == EXPR_RANGE) + break; + expr->left->ops->pctx_update(&ctx->pctx, expr); if (ctx->pbase == PROTO_BASE_INVALID &&