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=-8.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_SANE_2 autolearn=unavailable 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 90CB2C4360C for ; Fri, 4 Oct 2019 12:20:37 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 636BD2070B for ; Fri, 4 Oct 2019 12:20:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="kCU4ZHgv" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 636BD2070B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=mediatek.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Date:To:From:Subject:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Qmv8nyyqALQtlSn2133EYN1xzF1lKdnPXJSIVKY3K9Q=; b=kCU4ZHgviiCmGX cbZs87QOPiuAlcn/RfICk8CdngW7xw/gj2cjzZFp+dBkWQeRtcTKD3GR5hKKvgWv6a7AqAt0ayjW9 oaylVdQcB2vJ06F4ZkqEJUsLrx00K3RLfL0M3Jjq5goBsZQuWUil4Hocwc6Hh9EHx5FHVB0jNIeol 4S8PuRao/tWV6LGtpDrn1M1kVo0x0Ctt2W1UlTRQg1rLHw9OZDuadIw+zXw8ZRua5MJ5NXOFsDcyl e8uX7gCrZUpp37LFqG7m1hkD5ZRUUHRrzBo8l6vkBKWUAUeCNWPepsUm6QHmzhmC9rU+od2uvQ7J+ Ci/DQBU5/hd6+LGH3TPw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.2 #3 (Red Hat Linux)) id 1iGMZU-0008NE-8l; Fri, 04 Oct 2019 12:20:32 +0000 Received: from mailgw01.mediatek.com ([216.200.240.184]) by bombadil.infradead.org with esmtps (Exim 4.92.2 #3 (Red Hat Linux)) id 1iGMZQ-0008Mb-0Y; Fri, 04 Oct 2019 12:20:30 +0000 X-UUID: bab4cb1f439944c38de2cfd65e88482a-20191004 X-UUID: bab4cb1f439944c38de2cfd65e88482a-20191004 Received: from mtkcas68.mediatek.inc [(172.29.94.19)] by mailgw01.mediatek.com (envelope-from ) (musrelay.mediatek.com ESMTP with TLS) with ESMTP id 286974719; Fri, 04 Oct 2019 04:20:21 -0800 Received: from MTKMBS07N2.mediatek.inc (172.21.101.141) by MTKMBS62N1.mediatek.inc (172.29.193.41) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Fri, 4 Oct 2019 05:20:19 -0700 Received: from mtkcas08.mediatek.inc (172.21.101.126) by mtkmbs07n2.mediatek.inc (172.21.101.141) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Fri, 4 Oct 2019 20:05:16 +0800 Received: from [172.21.84.99] (172.21.84.99) by mtkcas08.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1395.4 via Frontend Transport; Fri, 4 Oct 2019 20:05:16 +0800 Message-ID: <1570190718.19702.125.camel@mtksdccf07> Subject: Re: [PATCH] kasan: fix the missing underflow in memmove and memcpy with CONFIG_KASAN_GENERIC=y From: Walter Wu To: Dmitry Vyukov Date: Fri, 4 Oct 2019 20:05:18 +0800 In-Reply-To: References: <20190927034338.15813-1-walter-zh.wu@mediatek.com> <1569594142.9045.24.camel@mtksdccf07> <1569818173.17361.19.camel@mtksdccf07> <1570018513.19702.36.camel@mtksdccf07> <1570069078.19702.57.camel@mtksdccf07> <1570095525.19702.59.camel@mtksdccf07> <1570110681.19702.64.camel@mtksdccf07> <1570164140.19702.97.camel@mtksdccf07> <1570176131.19702.105.camel@mtksdccf07> <1570182257.19702.109.camel@mtksdccf07> X-Mailer: Evolution 3.2.3-0ubuntu6 MIME-Version: 1.0 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191004_052028_065081_362B3725 X-CRM114-Status: GOOD ( 21.07 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: wsd_upstream , linux-mediatek@lists.infradead.org, LKML , kasan-dev , Linux-MM , Alexander Potapenko , Matthias Brugger , Andrey Ryabinin , Linux ARM Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, 2019-10-04 at 11:54 +0200, Dmitry Vyukov wrote: > > > "out-of-bounds" is the _least_ frequent KASAN bug type. So saying > > > "out-of-bounds" has downsides of both approaches and won't prevent > > > duplicate reports by syzbot... > > > > > maybe i should add your comment into the comment in get_bug_type? > > Yes, that's exactly what I meant above: > > "I would change get_bug_type() to return "slab-out-of-bounds" (as the > most common OOB) in such case (with a comment)." > > ;) The patchset help to produce KASAN report when size is negative size in memory operation function. It is helpful for programmer to solve the undefined behavior issue. Patch 1 based on Dmitry's suggestion and review, patch 2 is a test in order to verify the patch 1. [1]https://bugzilla.kernel.org/show_bug.cgi?id=199341 [2]https://lore.kernel.org/linux-arm-kernel/20190927034338.15813-1-walter-zh.wu@mediatek.com/ Walter Wu (2): kasan: detect invalid size in memory operation function kasan: add test for invalid size in memmove lib/test_kasan.c | 18 ++++++++++++++++++ mm/kasan/common.c | 13 ++++++++----- mm/kasan/generic.c | 5 +++++ mm/kasan/generic_report.c | 10 ++++++++++ mm/kasan/tags.c | 5 +++++ mm/kasan/tags_report.c | 10 ++++++++++ 6 files changed, 56 insertions(+), 5 deletions(-) commit 0bc50c759a425fa0aafb7ef623aa1598b3542c67 Author: Walter Wu Date: Fri Oct 4 18:38:31 2019 +0800 kasan: detect invalid size in memory operation function It is an undefined behavior to pass a negative value to memset()/memcpy()/memmove() , so need to be detected by KASAN. If size is negative value, then it will be larger than ULONG_MAX/2, so that we will qualify as out-of-bounds issue. KASAN report: BUG: KASAN: out-of-bounds in kmalloc_memmove_invalid_size+0x70/0xa0 Read of size 18446744073709551608 at addr ffffff8069660904 by task cat/72 CPU: 2 PID: 72 Comm: cat Not tainted 5.4.0-rc1-next-20191004ajb-00001-gdb8af2f372b2-dirty #1 Hardware name: linux,dummy-virt (DT) Call trace: dump_backtrace+0x0/0x288 show_stack+0x14/0x20 dump_stack+0x10c/0x164 print_address_description.isra.9+0x68/0x378 __kasan_report+0x164/0x1a0 kasan_report+0xc/0x18 check_memory_region+0x174/0x1d0 memmove+0x34/0x88 kmalloc_memmove_invalid_size+0x70/0xa0 [1] https://bugzilla.kernel.org/show_bug.cgi?id=199341 Signed-off-by: Walter Wu Reported -by: Dmitry Vyukov Suggested-by: Dmitry Vyukov diff --git a/mm/kasan/common.c b/mm/kasan/common.c index 6814d6d6a023..6ef0abd27f06 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -102,7 +102,8 @@ EXPORT_SYMBOL(__kasan_check_write); #undef memset void *memset(void *addr, int c, size_t len) { - check_memory_region((unsigned long)addr, len, true, _RET_IP_); + if (!check_memory_region((unsigned long)addr, len, true, _RET_IP_)) + return NULL; return __memset(addr, c, len); } @@ -110,8 +111,9 @@ void *memset(void *addr, int c, size_t len) #undef memmove void *memmove(void *dest, const void *src, size_t len) { - check_memory_region((unsigned long)src, len, false, _RET_IP_); - check_memory_region((unsigned long)dest, len, true, _RET_IP_); + if (!check_memory_region((unsigned long)src, len, false, _RET_IP_) || + !check_memory_region((unsigned long)dest, len, true, _RET_IP_)) + return NULL; return __memmove(dest, src, len); } @@ -119,8 +121,9 @@ void *memmove(void *dest, const void *src, size_t len) #undef memcpy void *memcpy(void *dest, const void *src, size_t len) { - check_memory_region((unsigned long)src, len, false, _RET_IP_); - check_memory_region((unsigned long)dest, len, true, _RET_IP_); + if (!check_memory_region((unsigned long)src, len, false, _RET_IP_) || + !check_memory_region((unsigned long)dest, len, true, _RET_IP_)) + return NULL; return __memcpy(dest, src, len); } diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c index 616f9dd82d12..02148a317d27 100644 --- a/mm/kasan/generic.c +++ b/mm/kasan/generic.c @@ -173,6 +173,11 @@ static __always_inline bool check_memory_region_inline(unsigned long addr, if (unlikely(size == 0)) return true; + if (unlikely((long)size < 0)) { + kasan_report(addr, size, write, ret_ip); + return false; + } + if (unlikely((void *)addr < kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) { kasan_report(addr, size, write, ret_ip); diff --git a/mm/kasan/generic_report.c b/mm/kasan/generic_report.c index 36c645939bc9..23951a453681 100644 --- a/mm/kasan/generic_report.c +++ b/mm/kasan/generic_report.c @@ -107,6 +107,16 @@ static const char *get_wild_bug_type(struct kasan_access_info *info) const char *get_bug_type(struct kasan_access_info *info) { + /* + * if access_size < 0, then it will be larger than ULONG_MAX/2, + * so that this can qualify as out-of-bounds. + * out-of-bounds is the _least_ frequent KASAN bug type. So saying + * out-of-bounds has downsides of both approaches and won't prevent + * duplicate reports by syzbot. + */ + if ((long)info->access_size < 0) + return "out-of-bounds"; + if (addr_has_shadow(info->access_addr)) return get_shadow_bug_type(info); return get_wild_bug_type(info); diff --git a/mm/kasan/tags.c b/mm/kasan/tags.c index 0e987c9ca052..b829535a3ad7 100644 --- a/mm/kasan/tags.c +++ b/mm/kasan/tags.c @@ -86,6 +86,11 @@ bool check_memory_region(unsigned long addr, size_t size, bool write, if (unlikely(size == 0)) return true; + if (unlikely((long)size < 0)) { + kasan_report(addr, size, write, ret_ip); + return false; + } + tag = get_tag((const void *)addr); /* diff --git a/mm/kasan/tags_report.c b/mm/kasan/tags_report.c index 969ae08f59d7..19b9e364b397 100644 --- a/mm/kasan/tags_report.c +++ b/mm/kasan/tags_report.c @@ -36,6 +36,16 @@ const char *get_bug_type(struct kasan_access_info *info) { + /* + * if access_size < 0, then it will be larger than ULONG_MAX/2, + * so that this can qualify as out-of-bounds. + * out-of-bounds is the _least_ frequent KASAN bug type. So saying + * out-of-bounds has downsides of both approaches and won't prevent + * duplicate reports by syzbot. + */ + if ((long)info->access_size < 0) + return "out-of-bounds"; + #ifdef CONFIG_KASAN_SW_TAGS_IDENTIFY struct kasan_alloc_meta *alloc_meta; struct kmem_cache *cache; commit fb5cf7bd16e939d1feef229af0211a8616c9ea03 Author: Walter Wu Date: Fri Oct 4 18:32:03 2019 +0800 kasan: add test for invalid size in memmove Test size is negative vaule in memmove in order to verify if it correctly produce KASAN report. Signed-off-by: Walter Wu diff --git a/lib/test_kasan.c b/lib/test_kasan.c index 49cc4d570a40..06942cf585cc 100644 --- a/lib/test_kasan.c +++ b/lib/test_kasan.c @@ -283,6 +283,23 @@ static noinline void __init kmalloc_oob_in_memset(void) kfree(ptr); } +static noinline void __init kmalloc_memmove_invalid_size(void) +{ + char *ptr; + size_t size = 64; + + pr_info("invalid size in memmove\n"); + ptr = kmalloc(size, GFP_KERNEL); + if (!ptr) { + pr_err("Allocation failed\n"); + return; + } + + memset((char *)ptr, 0, 64); + memmove((char *)ptr, (char *)ptr + 4, -2); + kfree(ptr); +} + static noinline void __init kmalloc_uaf(void) { char *ptr; @@ -773,6 +790,7 @@ static int __init kmalloc_tests_init(void) kmalloc_oob_memset_4(); kmalloc_oob_memset_8(); kmalloc_oob_memset_16(); + kmalloc_memmove_invalid_size(); kmalloc_uaf(); kmalloc_uaf_memset(); kmalloc_uaf2(); _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel