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h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=W721XQEkMG8bC4j2PepgMeY0jTQOErIpXztyfiJXOs8=; b=DdyfijP4/BLUp6cwPthT33WzfvjdYyUj2N9ZB4ZZZiBrDm0FEkEuiz5rcAY7j1fuH/ ItmvppydhuvVPzKIo8sHxY5EHNV8TPk4ylm21NBK9JALoNCxoSI+ZL46hXNPwrh1ZoDw 8AoIV9ecslfzKjQGpS1rChtN92En7xvURPYUyz49rNUsqUMkKXInXvnY/5+UWPCBO/O3 96wO3nXI5PNACjWRXhmDzmkJalhGrtId4sl8ermFBRNiwWrQ7JhaD7XFgWwM0xtRVlMk Oq37oFh8STUL81+4PFMz5t+gIWV/4TRNKb8uRpJ/9KNPMizLU1lP86DY5KfyMHQRZAUs ja5w== X-Gm-Message-State: APjAAAW729G8vwsTVzdj9uxvWUxNwEdBNR2rQDLhUM78iMUOrdRuROkC LLTHDc2ZjvIAu3KybQGVYOORhyM7Av6qRADmqlEXXQ== X-Google-Smtp-Source: APXvYqzCww2lW0PtxSg3odpkkA5VJF/XxD5kKaqrmZ1KDA7CF0CBSRDpFDrvufwyLOctz33+u6vqBpksBAlWIGv+72Q= X-Received: by 2002:a17:90a:ff08:: with SMTP id ce8mr4950627pjb.123.1567604688325; Wed, 04 Sep 2019 06:44:48 -0700 (PDT) MIME-Version: 1.0 References: <20190904065133.20268-1-walter-zh.wu@mediatek.com> In-Reply-To: <20190904065133.20268-1-walter-zh.wu@mediatek.com> From: Andrey Konovalov Date: Wed, 4 Sep 2019 15:44:37 +0200 Message-ID: Subject: Re: [PATCH 1/2] mm/kasan: dump alloc/free stack for page allocator To: Walter Wu Cc: Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , Matthias Brugger , Andrew Morton , Martin Schwidefsky , Arnd Bergmann , kasan-dev , Linux Memory Management List , LKML , Linux ARM , linux-mediatek@lists.infradead.org, wsd_upstream@mediatek.com Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Sep 4, 2019 at 8:51 AM Walter Wu wrote: > > This patch is KASAN report adds the alloc/free stacks for page allocator > in order to help programmer to see memory corruption caused by page. > > By default, KASAN doesn't record alloc/free stack for page allocator. > It is difficult to fix up page use-after-free issue. > > This feature depends on page owner to record the last stack of pages. > It is very helpful for solving the page use-after-free or out-of-bound. > > KASAN report will show the last stack of page, it may be: > a) If page is in-use state, then it prints alloc stack. > It is useful to fix up page out-of-bound issue. > > BUG: KASAN: slab-out-of-bounds in kmalloc_pagealloc_oob_right+0x88/0x90 > Write of size 1 at addr ffffffc0d64ea00a by task cat/115 > ... > Allocation stack of page: > prep_new_page+0x1a0/0x1d8 > get_page_from_freelist+0xd78/0x2748 > __alloc_pages_nodemask+0x1d4/0x1978 > kmalloc_order+0x28/0x58 > kmalloc_order_trace+0x28/0xe0 > kmalloc_pagealloc_oob_right+0x2c/0x90 > > b) If page is freed state, then it prints free stack. > It is useful to fix up page use-after-free issue. > > BUG: KASAN: use-after-free in kmalloc_pagealloc_uaf+0x70/0x80 > Write of size 1 at addr ffffffc0d651c000 by task cat/115 > ... > Free stack of page: > kasan_free_pages+0x68/0x70 > __free_pages_ok+0x3c0/0x1328 > __free_pages+0x50/0x78 > kfree+0x1c4/0x250 > kmalloc_pagealloc_uaf+0x38/0x80 > > > This has been discussed, please refer below link. > https://bugzilla.kernel.org/show_bug.cgi?id=203967 > > Signed-off-by: Walter Wu > --- > lib/Kconfig.kasan | 9 +++++++++ > mm/kasan/common.c | 6 ++++++ > 2 files changed, 15 insertions(+) > > diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan > index 4fafba1a923b..ba17f706b5f8 100644 > --- a/lib/Kconfig.kasan > +++ b/lib/Kconfig.kasan > @@ -135,6 +135,15 @@ config KASAN_S390_4_LEVEL_PAGING > to 3TB of RAM with KASan enabled). This options allows to force > 4-level paging instead. > > +config KASAN_DUMP_PAGE > + bool "Dump the page last stack information" > + depends on KASAN && PAGE_OWNER > + help > + By default, KASAN doesn't record alloc/free stack for page allocator. > + It is difficult to fix up page use-after-free issue. > + This feature depends on page owner to record the last stack of page. > + It is very helpful for solving the page use-after-free or out-of-bound. I'm not sure if we need a separate config for this. Is there any reason to not have this enabled by default? > + > config TEST_KASAN > tristate "Module for testing KASAN for bug detection" > depends on m && KASAN > diff --git a/mm/kasan/common.c b/mm/kasan/common.c > index 2277b82902d8..2a32474efa74 100644 > --- a/mm/kasan/common.c > +++ b/mm/kasan/common.c > @@ -35,6 +35,7 @@ > #include > #include > #include > +#include > > #include "kasan.h" > #include "../slab.h" > @@ -227,6 +228,11 @@ void kasan_alloc_pages(struct page *page, unsigned int order) > > void kasan_free_pages(struct page *page, unsigned int order) > { > +#ifdef CONFIG_KASAN_DUMP_PAGE > + gfp_t gfp_flags = GFP_KERNEL; > + > + set_page_owner(page, order, gfp_flags); > +#endif > if (likely(!PageHighMem(page))) > kasan_poison_shadow(page_address(page), > PAGE_SIZE << order, > -- > 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/20190904065133.20268-1-walter-zh.wu%40mediatek.com.