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 CEEC3C4360C for ; Fri, 4 Oct 2019 08:02:23 +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 A5068222CA for ; Fri, 4 Oct 2019 08:02:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="uiFsuvM0" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A5068222CA 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=vhSnsDFilwwVTthzPWe81BlmL3KAX7Z7JzwCt/hsSNc=; b=uiFsuvM0UNvPdY 2QA1jPAHeOL8NNGXsaQrbpWGzy6tsNAjEtIAvY6aAo+gjVpXVjrL15O8+sW5Dfa0afslglJ1NCuaO UbCRSbTwkCp0SCaTC2G2XjzWtYC8vYOvV5qzu02du3xtAtlxkfEdYsrny+xNpu/vXMqH5mFEQ2rd8 ryE6T0z05ntKnZLA8Fg+92gS25Fcg/ls28yW9HuWlNfjcgkaGhJsuBwwNJKqo9QA6DbqyyX0eey6z AS2FsscDBlHVzCd+/tzzhVI9o0CKqfmdbOaeJqoBPYV+OR7C8zdRg/f/k+NJkL9KUqb8qQSic8wCu Lu0ez3gnCOj9/hrmpaQA==; 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 1iGIXe-0005Fk-FF; Fri, 04 Oct 2019 08:02:22 +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 1iGIXb-0005Ee-9x; Fri, 04 Oct 2019 08:02:21 +0000 X-UUID: 5bb6f250c3cb40d692d4f7e9e8c16692-20191004 X-UUID: 5bb6f250c3cb40d692d4f7e9e8c16692-20191004 Received: from mtkcas66.mediatek.inc [(172.29.193.44)] by mailgw01.mediatek.com (envelope-from ) (musrelay.mediatek.com ESMTP with TLS) with ESMTP id 112094616; Fri, 04 Oct 2019 00:02:12 -0800 Received: from mtkmbs07n1.mediatek.inc (172.21.101.16) by MTKMBS62N1.mediatek.inc (172.29.193.41) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Fri, 4 Oct 2019 01:02:11 -0700 Received: from mtkcas07.mediatek.inc (172.21.101.84) by mtkmbs07n1.mediatek.inc (172.21.101.16) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Fri, 4 Oct 2019 16:02:10 +0800 Received: from [172.21.84.99] (172.21.84.99) by mtkcas07.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1395.4 via Frontend Transport; Fri, 4 Oct 2019 16:02:10 +0800 Message-ID: <1570176131.19702.105.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 16:02:11 +0800 In-Reply-To: <1570164140.19702.97.camel@mtksdccf07> 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> 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_010219_350995_69C6CAF8 X-CRM114-Status: GOOD ( 24.14 ) 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 12:42 +0800, Walter Wu wrote: > On Thu, 2019-10-03 at 16:53 +0200, Dmitry Vyukov wrote: > > On Thu, Oct 3, 2019 at 3:51 PM Walter Wu wrote:> > > > > > > static void print_error_description(struct kasan_access_info *info) > > > { > > > - pr_err("BUG: KASAN: %s in %pS\n", > > > - get_bug_type(info), (void *)info->ip); > > > - pr_err("%s of size %zu at addr %px by task %s/%d\n", > > > - info->is_write ? "Write" : "Read", info->access_size, > > > - info->access_addr, current->comm, task_pid_nr(current)); > > > + if ((long)info->access_size < 0) { > > > + pr_err("BUG: KASAN: invalid size %zu in %pS\n", > > > + info->access_size, (void *)info->ip); > > > > I would not introduce a new bug type. > > These are parsed and used by some systems, e.g. syzbot. If size is > > user-controllable, then a new bug type for this will mean 2 bug > > reports. > > It also won't harm to print Read/Write, definitely the address, so no > > reason to special case this out of a dozen of report formats. > > This can qualify as out-of-bounds (definitely will cross some > > bounds!), so I would change get_bug_type() to return > > "slab-out-of-bounds" (as the most common OOB) in such case (with a > > comment). > > > Print Read/Write and address information, it is ok. > But if we can directly point to the root cause of this problem, why we > not do it? see 1) and 2) to get a point, if we print OOB, then user > needs one minute to think what is root case of this problem, but if we > print invalid size, then user can directly get root case. this is my > original thinking. > 1)Invalid size is true then OOB is true. > 2)OOB is true then invalid size may be true or false. > > But I see you say some systems have used bug report so that avoid this > trouble, i will print the wrong type is "out-of-bound" in a unified way > when size<0. > Updated my patch, please help to review it. thanks. commit 13e10a7e4264eb25c5a14193068027afc9c261f6 Author: Walter-zh Wu Date: Fri Oct 4 15:27:17 2019 +0800 kasan: detect negative 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/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(); diff --git a/mm/kasan/common.c b/mm/kasan/common.c index 6814d6d6a023..97dd6eecc3e7 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); } @@ -110,7 +111,8 @@ 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_); + if (!check_memory_region((unsigned long)src, len, false, _RET_IP_)) + return NULL; check_memory_region((unsigned long)dest, len, true, _RET_IP_); return __memmove(dest, src, len); @@ -119,7 +121,8 @@ 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_); + if (!check_memory_region((unsigned long)src, len, false, _RET_IP_)) + return NULL; check_memory_region((unsigned long)dest, len, true, _RET_IP_); 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..ae9596210394 100644 --- a/mm/kasan/generic_report.c +++ b/mm/kasan/generic_report.c @@ -107,6 +107,13 @@ 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. + */ + 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..1e1ca81214b5 100644 --- a/mm/kasan/tags_report.c +++ b/mm/kasan/tags_report.c @@ -36,6 +36,13 @@ 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. + */ + 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; _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel