From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt1-x835.google.com (mail-qt1-x835.google.com [IPv6:2607:f8b0:4864:20::835]) by sourceware.org (Postfix) with ESMTPS id C5DDA3858C50 for ; Tue, 4 Oct 2022 21:33:06 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org C5DDA3858C50 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=gmail.com Received: by mail-qt1-x835.google.com with SMTP id gb14so8961561qtb.3 for ; Tue, 04 Oct 2022 14:33:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date; bh=+2tk+SkZENIIkckm+nlBOcKBpSLC0c+8tRB2vl2fhVE=; b=GhE6FKbRPJo09A0ckdb5YU3OFZhbXjJHxQKsgqIxX09qL9NNws/+PBj2JqxBxY/vKj 9O4fdkmnmRU2HWvAV09w26Pvck4EfWs1ogfnSP6ySYDJko1HMFq6mImqR5/JlUSfJTA8 vFY1FerPoqrzYpkVFAv1zh0lktjms9LV/bidWSUd3IVGtIb7eWMMNmRfRBcAdax3Wobn /uWkUANpbtC1BmnX3pCry+KLCyDHGXRcgCb+M7AqRviJm7FkLCpFPqhPlPVt45DNQb4q YUwCgOxzq0yjeRFCDIQo0ltQLvVdfvaoewJTkFvnA/cYAMAGdhVL7P8p8h/V7gdiyHKB HEkQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date; bh=+2tk+SkZENIIkckm+nlBOcKBpSLC0c+8tRB2vl2fhVE=; b=kZVV8P1L0a1CIzgf/uy/krR4/ex06+tcBjBGHPnGR/zaia1lmv3qHoLloedLxTbiUe IKy650b1PeMcV8aQTh+RAFSRv8QWUII8uBDFLR2mUa18yzbFYmgbJCj5OO/dPtTb8npU 5s3BGOVVvTFWa6mJb0lIgAgsrQGKjhiooILjaDC5jMzwRxE4lksfaWgLenf8zKv2ehRP +u/G9hAbweJSf04v9QyMOmdA+mLg6zx2DxhaLmzFaAMFiX05swigedTKs3ATK52ylX74 9qVfEHfFob0NfM+gD1F37KDSJ/RIi2sCbFJNuDtVIkeRYVAA6Q8K+dC38ebH5imqEGFt ODPg== X-Gm-Message-State: ACrzQf2tWsyud5azI/RC7SzSWF7y/IIXTE/xU+j8T4BYzjjy++Npi09x Pu+LL0MSsHOIu/QB49gATG38eKwDxhaRWancvWDkbGtK X-Google-Smtp-Source: AMsMyM76d3r4GaZkWHI8q05r0WALXW9J6S6E2RRJ1ZOy9Tks5GeCeKEmRfG3rMSAprjp5Hs0HhdtWd5dhGpbgjsniLs= X-Received: by 2002:a05:622a:1387:b0:35c:bbb2:d1d3 with SMTP id o7-20020a05622a138700b0035cbbb2d1d3mr21173073qtk.436.1664919185877; Tue, 04 Oct 2022 14:33:05 -0700 (PDT) MIME-Version: 1.0 References: <20220921204206.95480-1-hjl.tools@gmail.com> In-Reply-To: <20220921204206.95480-1-hjl.tools@gmail.com> From: "H.J. Lu" Date: Tue, 4 Oct 2022 14:32:29 -0700 Message-ID: Subject: PING^1: [PATCH] x86: Check corrupted return address when unwinding stack To: GCC Patches , Hongtao Liu Cc: Uros Bizjak Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-3024.7 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM,GIT_PATCH_0,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On Wed, Sep 21, 2022 at 1:42 PM H.J. Lu wrote: > > If shadow stack is enabled, when unwinding stack, we count how many stack > frames we pop to reach the landing pad and adjust shadow stack by the same > amount. When counting the stack frame, we compare the return address on > normal stack against the return address on shadow stack. If they don't > match, return _URC_FATAL_PHASE2_ERROR for the corrupted return address on > normal stack. Don't check the return address for > > 1. Non-catchable exception where exception_class == 0. Process will be > terminated. > 2. Zero return address which marks the outermost stack frame. > 3. Signal stack frame since kernel puts a restore token on shadow stack. > > * unwind-generic.h (_Unwind_Frames_Increment): Add the EXC > argument. > * unwind.inc (_Unwind_RaiseException_Phase2): Pass EXC to > _Unwind_Frames_Increment. > (_Unwind_ForcedUnwind_Phase2): Likewise. > * config/i386/shadow-stack-unwind.h (_Unwind_Frames_Increment): > Take the EXC argument. Return _URC_FATAL_PHASE2_ERROR if the > return address on normal stack doesn't match the return address > on shadow stack. > --- > libgcc/config/i386/shadow-stack-unwind.h | 51 ++++++++++++++++++++++-- > libgcc/unwind-generic.h | 2 +- > libgcc/unwind.inc | 4 +- > 3 files changed, 50 insertions(+), 7 deletions(-) > > diff --git a/libgcc/config/i386/shadow-stack-unwind.h b/libgcc/config/i386/shadow-stack-unwind.h > index 2b02682bdae..89d44165000 100644 > --- a/libgcc/config/i386/shadow-stack-unwind.h > +++ b/libgcc/config/i386/shadow-stack-unwind.h > @@ -54,10 +54,39 @@ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see > aligned. If the original shadow stack is 8 byte aligned, we just > need to pop 2 slots, one restore token, from shadow stack. Otherwise, > we need to pop 3 slots, one restore token + 4 byte padding, from > - shadow stack. */ > -#ifndef __x86_64__ > + shadow stack. > + > + When popping a stack frame, we compare the return address on normal > + stack against the return address on shadow stack. If they don't match, > + return _URC_FATAL_PHASE2_ERROR for the corrupted return address on > + normal stack. Don't check the return address for > + 1. Non-catchable exception where exception_class == 0. Process will > + be terminated. > + 2. Zero return address which marks the outermost stack frame. > + 3. Signal stack frame since kernel puts a restore token on shadow > + stack. > + */ > #undef _Unwind_Frames_Increment > -#define _Unwind_Frames_Increment(context, frames) \ > +#ifdef __x86_64__ > +#define _Unwind_Frames_Increment(exc, context, frames) \ > + { \ > + frames++; \ > + if (exc->exception_class != 0 \ > + && _Unwind_GetIP (context) != 0 \ > + && !_Unwind_IsSignalFrame (context)) \ > + { \ > + _Unwind_Word ssp = _get_ssp (); \ > + if (ssp != 0) \ > + { \ > + ssp += 8 * frames; \ > + _Unwind_Word ra = *(_Unwind_Word *) ssp; \ > + if (ra != _Unwind_GetIP (context)) \ > + return _URC_FATAL_PHASE2_ERROR; \ > + } \ > + } \ > + } > +#else > +#define _Unwind_Frames_Increment(exc, context, frames) \ > if (_Unwind_IsSignalFrame (context)) \ > do \ > { \ > @@ -83,5 +112,19 @@ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see > } \ > while (0); \ > else \ > - frames++; > + { \ > + frames++; \ > + if (exc->exception_class != 0 \ > + && _Unwind_GetIP (context) != 0) \ > + { \ > + _Unwind_Word ssp = _get_ssp (); \ > + if (ssp != 0) \ > + { \ > + ssp += 4 * frames; \ > + _Unwind_Word ra = *(_Unwind_Word *) ssp; \ > + if (ra != _Unwind_GetIP (context)) \ > + return _URC_FATAL_PHASE2_ERROR; \ > + } \ > + } \ > + } > #endif > diff --git a/libgcc/unwind-generic.h b/libgcc/unwind-generic.h > index a87c9b3ccf6..bf721282d03 100644 > --- a/libgcc/unwind-generic.h > +++ b/libgcc/unwind-generic.h > @@ -292,6 +292,6 @@ EXCEPTION_DISPOSITION _GCC_specific_handler (PEXCEPTION_RECORD, void *, > #define _Unwind_Frames_Extra(frames) > > /* Increment frame count. */ > -#define _Unwind_Frames_Increment(context, frames) frames++ > +#define _Unwind_Frames_Increment(exc, context, frames) frames++ > > #endif /* unwind.h */ > diff --git a/libgcc/unwind.inc b/libgcc/unwind.inc > index 5efd8af1b15..a7111a7b3a8 100644 > --- a/libgcc/unwind.inc > +++ b/libgcc/unwind.inc > @@ -73,7 +73,7 @@ _Unwind_RaiseException_Phase2(struct _Unwind_Exception *exc, > gcc_assert (!match_handler); > > uw_update_context (context, &fs); > - _Unwind_Frames_Increment (context, frames); > + _Unwind_Frames_Increment (exc, context, frames); > } > > *frames_p = frames; > @@ -191,7 +191,7 @@ _Unwind_ForcedUnwind_Phase2 (struct _Unwind_Exception *exc, > /* Update cur_context to describe the same frame as fs, and discard > the previous context if necessary. */ > uw_advance_context (context, &fs); > - _Unwind_Frames_Increment (context, frames); > + _Unwind_Frames_Increment (exc, context, frames); > } > > *frames_p = frames; > -- > 2.37.3 > PING. Jeff has approved the generic changes. Thanks. -- H.J.