From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-14.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B67FBC433E0 for ; Mon, 25 May 2020 09:56:45 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 64839207CB for ; Mon, 25 May 2020 09:56:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="pw328Wov" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 64839207CB Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id E075B8E0007; Mon, 25 May 2020 05:56:44 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id DDD348E0003; Mon, 25 May 2020 05:56:44 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CF3E28E0007; Mon, 25 May 2020 05:56:44 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0134.hostedemail.com [216.40.44.134]) by kanga.kvack.org (Postfix) with ESMTP id B767D8E0003 for ; Mon, 25 May 2020 05:56:44 -0400 (EDT) Received: from smtpin10.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 7DE9E180AD81D for ; Mon, 25 May 2020 09:56:44 +0000 (UTC) X-FDA: 76854787128.10.sun54_57ea045b0f935 X-HE-Tag: sun54_57ea045b0f935 X-Filterd-Recvd-Size: 13939 Received: from mail-qt1-f195.google.com (mail-qt1-f195.google.com [209.85.160.195]) by imf15.hostedemail.com (Postfix) with ESMTP for ; Mon, 25 May 2020 09:56:44 +0000 (UTC) Received: by mail-qt1-f195.google.com with SMTP id y1so2724706qtv.12 for ; Mon, 25 May 2020 02:56:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=xgy4pPwZvtj+TPA9hBH3u2ab7Rd+oEJ+C7zugCqkjSE=; b=pw328WoviOHNUOb1wemFaEh4oU0CaeEryBB1HVU7jb147EtirSWXnc0Of7pyUsNu/4 Y31/bMG5OvVNXmKEjQ2/bHn0cZ9y6J4idnng1OsJm1L+Y2NW3XZftCQU2LJ4hsFAneOg M1rzrheRn/j4ngjNQd4a1v0NtSNPTSbzLmPi1peQ/MyJptaia97iIkMW4m5oxafw0190 coEeM3qQTHgMTa9BNYQOGJthlqc+LP7TRouNoPLnRCEgpcqeyqRpEJYoYDFxbP13FoZW Uhv4sTdhXxYXwzUldUOTPDokZrmVvlh+P8XtQeSk/w6PGLYmLOF+3yJRzVnT5+GDnCEX l2Sw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=xgy4pPwZvtj+TPA9hBH3u2ab7Rd+oEJ+C7zugCqkjSE=; b=BFkjuFyQg246jx5EDjl+0pfCxibwDiFFJ5d15CsmOLQhaMoYsixc3Fd3UAeDLdngAN NloketHqa0J/vMwuq17luWQEIjhetifZ5Zg7FHsHGL49r45cuyNDgeBpHG/taHcQGMGr ohfEVJZ+qzwewC6h4t1gPecl4MPdIrl5ypc5hoZu2fTBEE8P7XNkWzGJ8U88/lziQAae 5l3K5rWVK4p8bP+7exssKQ/hG4VTk9u3KH5wde4FgwY08bwgc+3YkPFGRpVJx28lN8ZL 78v03hOKVGSUq4lrzTlflEgO5Jy4LQLc6u44PbmW1ki+z+jxEQYBhop9pIOvEaq/Qs82 mYcQ== X-Gm-Message-State: AOAM530Kju8p8t2w4311CeKOy8iUFBZp7QB3ZjqcpPCCn5JOa8XzLwIt GzB05vpsaXadXbcysyQZsi8/OJab2UCaiyV4Vui1Ng== X-Google-Smtp-Source: ABdhPJy53jIyAXr/dV5k2cbIvijNG4i6QjG5uYS4h1FkoY3idjBusgFR602TYASb0QHlcI3nl2a+YNyE94DXEir5TpU= X-Received: by 2002:ac8:260b:: with SMTP id u11mr27310502qtu.380.1590400603220; Mon, 25 May 2020 02:56:43 -0700 (PDT) MIME-Version: 1.0 References: <20200522020127.23335-1-walter-zh.wu@mediatek.com> In-Reply-To: <20200522020127.23335-1-walter-zh.wu@mediatek.com> From: Dmitry Vyukov Date: Mon, 25 May 2020 11:56:32 +0200 Message-ID: Subject: Re: [PATCH v6 2/4] kasan: record and print the free track To: Walter Wu Cc: Andrey Ryabinin , Alexander Potapenko , kasan-dev , Linux-MM , LKML , Linux ARM , wsd_upstream , linux-mediatek@lists.infradead.org Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, May 22, 2020 at 4:01 AM Walter Wu wrote: > > Move free track from kasan_alloc_meta to kasan_free_meta in order > to make struct kasan_alloc_meta and kasan_free_meta size are both > 16 bytes. It is a good size because it is the minimal redzone size > and a good number of alignment. > > For free track, we make some modifications as shown below: > 1) Remove the free_track from struct kasan_alloc_meta. > 2) Add the free_track into struct kasan_free_meta. > 3) Add a macro KASAN_KMALLOC_FREETRACK in order to check whether > it can print free stack in KASAN report. > > [1]https://bugzilla.kernel.org/show_bug.cgi?id=198437 Reviewed-and-tested-by: Dmitry Vyukov > Signed-off-by: Walter Wu > Suggested-by: Dmitry Vyukov > Co-developed-by: Dmitry Vyukov > Cc: Andrey Ryabinin > Cc: Dmitry Vyukov > Cc: Alexander Potapenko > --- > mm/kasan/common.c | 22 ++-------------------- > mm/kasan/generic.c | 22 ++++++++++++++++++++++ > mm/kasan/generic_report.c | 1 + > mm/kasan/kasan.h | 13 +++++++++++-- > mm/kasan/quarantine.c | 1 + > mm/kasan/report.c | 26 ++++---------------------- > mm/kasan/tags.c | 37 +++++++++++++++++++++++++++++++++++++ > 7 files changed, 78 insertions(+), 44 deletions(-) > > diff --git a/mm/kasan/common.c b/mm/kasan/common.c > index 8bc618289bb1..47b53912f322 100644 > --- a/mm/kasan/common.c > +++ b/mm/kasan/common.c > @@ -51,7 +51,7 @@ depot_stack_handle_t kasan_save_stack(gfp_t flags) > return stack_depot_save(entries, nr_entries, flags); > } > > -static inline void set_track(struct kasan_track *track, gfp_t flags) > +void kasan_set_track(struct kasan_track *track, gfp_t flags) > { > track->pid = current->pid; > track->stack = kasan_save_stack(flags); > @@ -299,24 +299,6 @@ struct kasan_free_meta *get_free_info(struct kmem_cache *cache, > return (void *)object + cache->kasan_info.free_meta_offset; > } > > - > -static void kasan_set_free_info(struct kmem_cache *cache, > - void *object, u8 tag) > -{ > - struct kasan_alloc_meta *alloc_meta; > - u8 idx = 0; > - > - alloc_meta = get_alloc_info(cache, object); > - > -#ifdef CONFIG_KASAN_SW_TAGS_IDENTIFY > - idx = alloc_meta->free_track_idx; > - alloc_meta->free_pointer_tag[idx] = tag; > - alloc_meta->free_track_idx = (idx + 1) % KASAN_NR_FREE_STACKS; > -#endif > - > - set_track(&alloc_meta->free_track[idx], GFP_NOWAIT); > -} > - > void kasan_poison_slab(struct page *page) > { > unsigned long i; > @@ -492,7 +474,7 @@ static void *__kasan_kmalloc(struct kmem_cache *cache, const void *object, > KASAN_KMALLOC_REDZONE); > > if (cache->flags & SLAB_KASAN) > - set_track(&get_alloc_info(cache, object)->alloc_track, flags); > + kasan_set_track(&get_alloc_info(cache, object)->alloc_track, flags); > > return set_tag(object, tag); > } > diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c > index 8acf48882ba2..4b3cbad7431b 100644 > --- a/mm/kasan/generic.c > +++ b/mm/kasan/generic.c > @@ -346,3 +346,25 @@ void kasan_record_aux_stack(void *addr) > alloc_info->aux_stack[1] = alloc_info->aux_stack[0]; > alloc_info->aux_stack[0] = kasan_save_stack(GFP_NOWAIT); > } > + > +void kasan_set_free_info(struct kmem_cache *cache, > + void *object, u8 tag) > +{ > + struct kasan_free_meta *free_meta; > + > + free_meta = get_free_info(cache, object); > + kasan_set_track(&free_meta->free_track, GFP_NOWAIT); > + > + /* > + * the object was freed and has free track set > + */ > + *(u8 *)kasan_mem_to_shadow(object) = KASAN_KMALLOC_FREETRACK; > +} > + > +struct kasan_track *kasan_get_free_track(struct kmem_cache *cache, > + void *object, u8 tag) > +{ > + if (*(u8 *)kasan_mem_to_shadow(object) != KASAN_KMALLOC_FREETRACK) > + return NULL; > + return &get_free_info(cache, object)->free_track; > +} > diff --git a/mm/kasan/generic_report.c b/mm/kasan/generic_report.c > index e200acb2d292..a38c7a9e192a 100644 > --- a/mm/kasan/generic_report.c > +++ b/mm/kasan/generic_report.c > @@ -80,6 +80,7 @@ static const char *get_shadow_bug_type(struct kasan_access_info *info) > break; > case KASAN_FREE_PAGE: > case KASAN_KMALLOC_FREE: > + case KASAN_KMALLOC_FREETRACK: > bug_type = "use-after-free"; > break; > case KASAN_ALLOCA_LEFT: > diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h > index a7391bc83070..ef655a1c6e15 100644 > --- a/mm/kasan/kasan.h > +++ b/mm/kasan/kasan.h > @@ -17,15 +17,17 @@ > #define KASAN_PAGE_REDZONE 0xFE /* redzone for kmalloc_large allocations */ > #define KASAN_KMALLOC_REDZONE 0xFC /* redzone inside slub object */ > #define KASAN_KMALLOC_FREE 0xFB /* object was freed (kmem_cache_free/kfree) */ > +#define KASAN_KMALLOC_FREETRACK 0xFA /* object was freed and has free track set */ > #else > #define KASAN_FREE_PAGE KASAN_TAG_INVALID > #define KASAN_PAGE_REDZONE KASAN_TAG_INVALID > #define KASAN_KMALLOC_REDZONE KASAN_TAG_INVALID > #define KASAN_KMALLOC_FREE KASAN_TAG_INVALID > +#define KASAN_KMALLOC_FREETRACK KASAN_TAG_INVALID > #endif > > -#define KASAN_GLOBAL_REDZONE 0xFA /* redzone for global variable */ > -#define KASAN_VMALLOC_INVALID 0xF9 /* unallocated space in vmapped page */ > +#define KASAN_GLOBAL_REDZONE 0xF9 /* redzone for global variable */ > +#define KASAN_VMALLOC_INVALID 0xF8 /* unallocated space in vmapped page */ > > /* > * Stack redzone shadow values > @@ -127,6 +129,9 @@ struct kasan_free_meta { > * Otherwise it might be used for the allocator freelist. > */ > struct qlist_node quarantine_link; > +#ifdef CONFIG_KASAN_GENERIC > + struct kasan_track free_track; > +#endif > }; > > struct kasan_alloc_meta *get_alloc_info(struct kmem_cache *cache, > @@ -168,6 +173,10 @@ void kasan_report_invalid_free(void *object, unsigned long ip); > struct page *kasan_addr_to_page(const void *addr); > > depot_stack_handle_t kasan_save_stack(gfp_t flags); > +void kasan_set_track(struct kasan_track *track, gfp_t flags); > +void kasan_set_free_info(struct kmem_cache *cache, void *object, u8 tag); > +struct kasan_track *kasan_get_free_track(struct kmem_cache *cache, > + void *object, u8 tag); > > #if defined(CONFIG_KASAN_GENERIC) && \ > (defined(CONFIG_SLAB) || defined(CONFIG_SLUB)) > diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c > index 978bc4a3eb51..4c5375810449 100644 > --- a/mm/kasan/quarantine.c > +++ b/mm/kasan/quarantine.c > @@ -145,6 +145,7 @@ static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache) > if (IS_ENABLED(CONFIG_SLAB)) > local_irq_save(flags); > > + *(u8 *)kasan_mem_to_shadow(object) = KASAN_KMALLOC_FREE; > ___cache_free(cache, object, _THIS_IP_); > > if (IS_ENABLED(CONFIG_SLAB)) > diff --git a/mm/kasan/report.c b/mm/kasan/report.c > index 2421a4bd9227..fed3c8fdfd25 100644 > --- a/mm/kasan/report.c > +++ b/mm/kasan/report.c > @@ -164,26 +164,6 @@ static void describe_object_addr(struct kmem_cache *cache, void *object, > (void *)(object_addr + cache->object_size)); > } > > -static struct kasan_track *kasan_get_free_track(struct kmem_cache *cache, > - void *object, u8 tag) > -{ > - struct kasan_alloc_meta *alloc_meta; > - int i = 0; > - > - alloc_meta = get_alloc_info(cache, object); > - > -#ifdef CONFIG_KASAN_SW_TAGS_IDENTIFY > - for (i = 0; i < KASAN_NR_FREE_STACKS; i++) { > - if (alloc_meta->free_pointer_tag[i] == tag) > - break; > - } > - if (i == KASAN_NR_FREE_STACKS) > - i = alloc_meta->free_track_idx; > -#endif > - > - return &alloc_meta->free_track[i]; > -} > - > static void describe_object(struct kmem_cache *cache, void *object, > const void *addr, u8 tag) > { > @@ -195,8 +175,10 @@ static void describe_object(struct kmem_cache *cache, void *object, > print_track(&alloc_info->alloc_track, "Allocated"); > pr_err("\n"); > free_track = kasan_get_free_track(cache, object, tag); > - print_track(free_track, "Freed"); > - pr_err("\n"); > + if (free_track) { > + print_track(free_track, "Freed"); > + pr_err("\n"); > + } > > #ifdef CONFIG_KASAN_GENERIC > if (alloc_info->aux_stack[0]) { > diff --git a/mm/kasan/tags.c b/mm/kasan/tags.c > index 25b7734e7013..201dee5d6ae0 100644 > --- a/mm/kasan/tags.c > +++ b/mm/kasan/tags.c > @@ -162,3 +162,40 @@ void __hwasan_tag_memory(unsigned long addr, u8 tag, unsigned long size) > kasan_poison_shadow((void *)addr, size, tag); > } > EXPORT_SYMBOL(__hwasan_tag_memory); > + > +void kasan_set_free_info(struct kmem_cache *cache, > + void *object, u8 tag) > +{ > + struct kasan_alloc_meta *alloc_meta; > + u8 idx = 0; > + > + alloc_meta = get_alloc_info(cache, object); > + > +#ifdef CONFIG_KASAN_SW_TAGS_IDENTIFY > + idx = alloc_meta->free_track_idx; > + alloc_meta->free_pointer_tag[idx] = tag; > + alloc_meta->free_track_idx = (idx + 1) % KASAN_NR_FREE_STACKS; > +#endif > + > + kasan_set_track(&alloc_meta->free_track[idx], GFP_NOWAIT); > +} > + > +struct kasan_track *kasan_get_free_track(struct kmem_cache *cache, > + void *object, u8 tag) > +{ > + struct kasan_alloc_meta *alloc_meta; > + int i = 0; > + > + alloc_meta = get_alloc_info(cache, object); > + > +#ifdef CONFIG_KASAN_SW_TAGS_IDENTIFY > + for (i = 0; i < KASAN_NR_FREE_STACKS; i++) { > + if (alloc_meta->free_pointer_tag[i] == tag) > + break; > + } > + if (i == KASAN_NR_FREE_STACKS) > + i = alloc_meta->free_track_idx; > +#endif > + > + return &alloc_meta->free_track[i]; > +} > -- > 2.18.0 > > -- > You received this message because you are subscribed to the Google Groups "kasan-dev" group. > To unsubscribe from this group and stop receiving emails from it, send an email to kasan-dev+unsubscribe@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgid/kasan-dev/20200522020127.23335-1-walter-zh.wu%40mediatek.com.