From patchwork Mon Jul 25 11:20:25 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Feng Tang X-Patchwork-Id: 12927973 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 104F1C433EF for ; Mon, 25 Jul 2022 11:20:28 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 9592E940012; Mon, 25 Jul 2022 07:20:28 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8E2FF940011; Mon, 25 Jul 2022 07:20:28 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 78224940012; Mon, 25 Jul 2022 07:20:28 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 6986A940011 for ; Mon, 25 Jul 2022 07:20:28 -0400 (EDT) Received: from smtpin08.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 2F85916041D for ; Mon, 25 Jul 2022 11:20:28 +0000 (UTC) X-FDA: 79725378936.08.72CEAED Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by imf23.hostedemail.com (Postfix) with ESMTP id 5CC0C1400A0 for ; Mon, 25 Jul 2022 11:20:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1658748027; x=1690284027; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=jO7Qfg0Y0D/pt+R0i8YlAmlDiXdD9EWn6RIk91qRj78=; b=ECRFXq1KzuqgfgZmaW6FWskeB/NJq8J9IuGcNMJUgezScM0dKgvF3mmf j0D4vVWuI3xhIJLm/NFUFnNa2vBJ62n1229gTleZ3rotT+MGncg2/lgBL ZuLHG4e5+jAgnc+YcGsHLbHzDtI5JkaOUnUxomFqvU+L2I1lPFZKiwZzW dXbbgItUX+Nt6yFllNkSKWCxyr9hF94TSbsXK5gHGJzHRmgNi0wyg7WIx I90g/OlphZ3g/zyv+56knEZ9r/wWLd95lxdHiEpmQHkqikKR9QAMwAAB9 Dttdvc+66hU+sJLwKUC/LCTOvt8J5s1ffMwWAeAZMOp6s5DTdKBnA96sF Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10418"; a="286432936" X-IronPort-AV: E=Sophos;i="5.93,192,1654585200"; d="scan'208";a="286432936" Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Jul 2022 04:20:26 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.93,192,1654585200"; d="scan'208";a="549954155" Received: from shbuild999.sh.intel.com ([10.239.146.138]) by orsmga003.jf.intel.com with ESMTP; 25 Jul 2022 04:20:23 -0700 From: Feng Tang To: Andrew Morton , Vlastimil Babka , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Dave Hansen , Robin Murphy , John Garry , Feng Tang Subject: [PATCH v2 2/2] mm/slub: extend redzone check to cover all allocated kmalloc space Date: Mon, 25 Jul 2022 19:20:25 +0800 Message-Id: <20220725112025.22625-2-feng.tang@intel.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20220725112025.22625-1-feng.tang@intel.com> References: <20220725112025.22625-1-feng.tang@intel.com> MIME-Version: 1.0 ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1658748027; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=VlvDlmcARPY7rO7aHlXSzBAsS0HgE5b/60ni+SKqTAE=; b=5XuF0ej1f2/40C2w8nGW/zwBK8JNDaF0D82IoMHs85eSBFLXlj07aYzg0KDj4iQr7EHysd 1BpzCIoIRHrHnboCwvzA7caez6MSywAFdMfNY7uf3te42DCz5F4UVtCNzDMi+viMZZf8GC 79Jjui2whijsjampKq1hBNnQUPdSXuI= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=ECRFXq1K; spf=none (imf23.hostedemail.com: domain of feng.tang@intel.com has no SPF policy when checking 192.55.52.120) smtp.mailfrom=feng.tang@intel.com; dmarc=pass (policy=none) header.from=intel.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1658748027; a=rsa-sha256; cv=none; b=nvWldLMGyLKCVtDrw6MF3vP/E2zvq97GoOYJvh6E2Jo914FQ69hE1osYwVyj6jSrbitd3b fajkNIvsaPwJln1HDFZ3uYj0Zw9hnxkAOlpEVyP2JLJi0AO9flCg/dv+lK8lJuG4pOaH5H gpWUSAHWRQmCokbBJT8cAcVEIanme8U= X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 5CC0C1400A0 X-Stat-Signature: tdzw39o75hzrhb8onpa3i65tp6jorp3h X-Rspam-User: Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=ECRFXq1K; spf=none (imf23.hostedemail.com: domain of feng.tang@intel.com has no SPF policy when checking 192.55.52.120) smtp.mailfrom=feng.tang@intel.com; dmarc=pass (policy=none) header.from=intel.com X-HE-Tag: 1658748027-952982 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: kmalloc will round up the request size to a fixes size (mostly power of 2), so there could be a extra space than what user request, whose size is the actual buffer size minus original request size. To better detect out of bound access or abuse of this space, add redzone sannity check for it. And in current kernel, some kmalloc user already knows the existence of the space and utilize it after calling 'ksize()' to know the real size of the allocated buffer. So we skip the sanity check for objects which have been called with ksize(), as treating them as legitimate users. Suggested-by: Vlastimil Babka Signed-off-by: Feng Tang --- Hi reviewers, I'm not sure if I should carve out the legitimizing ksize() check and kzalloc() zeroing buffer to separate ones, and just put them together as one patch. pls let me know if you think this should be separated. Thanks, Feng mm/slab.c | 8 ++++---- mm/slab.h | 9 +++++++-- mm/slub.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++------- 3 files changed, 57 insertions(+), 13 deletions(-) diff --git a/mm/slab.c b/mm/slab.c index f8cd00f4ba13..9501510c3940 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -3236,7 +3236,7 @@ slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid, size_t orig_ init = slab_want_init_on_alloc(flags, cachep); out_hooks: - slab_post_alloc_hook(cachep, objcg, flags, 1, &ptr, init); + slab_post_alloc_hook(cachep, objcg, flags, 1, &ptr, init, 0); return ptr; } @@ -3299,7 +3299,7 @@ slab_alloc(struct kmem_cache *cachep, struct list_lru *lru, gfp_t flags, init = slab_want_init_on_alloc(flags, cachep); out: - slab_post_alloc_hook(cachep, objcg, flags, 1, &objp, init); + slab_post_alloc_hook(cachep, objcg, flags, 1, &objp, init, 0); return objp; } @@ -3546,13 +3546,13 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, * Done outside of the IRQ disabled section. */ slab_post_alloc_hook(s, objcg, flags, size, p, - slab_want_init_on_alloc(flags, s)); + slab_want_init_on_alloc(flags, s), 0); /* FIXME: Trace call missing. Christoph would like a bulk variant */ return size; error: local_irq_enable(); cache_alloc_debugcheck_after_bulk(s, flags, i, p, _RET_IP_); - slab_post_alloc_hook(s, objcg, flags, i, p, false); + slab_post_alloc_hook(s, objcg, flags, i, p, false, 0); __kmem_cache_free_bulk(s, i, p); return 0; } diff --git a/mm/slab.h b/mm/slab.h index db9fb5c8dae7..806822c78d24 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -733,12 +733,17 @@ static inline struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s, static inline void slab_post_alloc_hook(struct kmem_cache *s, struct obj_cgroup *objcg, gfp_t flags, - size_t size, void **p, bool init) + size_t size, void **p, bool init, + unsigned int orig_size) { size_t i; flags &= gfp_allowed_mask; + /* If original request size(kmalloc) is not set, use object_size */ + if (!orig_size) + orig_size = s->object_size; + /* * As memory initialization might be integrated into KASAN, * kasan_slab_alloc and initialization memset must be @@ -749,7 +754,7 @@ static inline void slab_post_alloc_hook(struct kmem_cache *s, for (i = 0; i < size; i++) { p[i] = kasan_slab_alloc(s, p[i], flags, init); if (p[i] && init && !kasan_has_integrated_init()) - memset(p[i], 0, s->object_size); + memset(p[i], 0, orig_size); kmemleak_alloc_recursive(p[i], s->object_size, 1, s->flags, flags); } diff --git a/mm/slub.c b/mm/slub.c index 9763a38bc4f0..8f3314f0725d 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -193,8 +193,8 @@ static inline bool kmem_cache_debug(struct kmem_cache *s) static inline bool slub_debug_orig_size(struct kmem_cache *s) { - return (s->flags & SLAB_KMALLOC && - kmem_cache_debug_flags(s, SLAB_STORE_USER)); + return (kmem_cache_debug_flags(s, SLAB_STORE_USER | SLAB_RED_ZONE) && + (s->flags & SLAB_KMALLOC)); } void *fixup_red_left(struct kmem_cache *s, void *p) @@ -838,6 +838,11 @@ static inline void set_orig_size(struct kmem_cache *s, *(unsigned int *)p = orig_size; } +static inline void skip_orig_size_check(struct kmem_cache *s, const void *object) +{ + set_orig_size(s, (void *)object, s->object_size); +} + static unsigned int get_orig_size(struct kmem_cache *s, void *object) { void *p = kasan_reset_tag(object); @@ -970,13 +975,28 @@ static __printf(3, 4) void slab_err(struct kmem_cache *s, struct slab *slab, static void init_object(struct kmem_cache *s, void *object, u8 val) { u8 *p = kasan_reset_tag(object); + unsigned int orig_size = s->object_size; if (s->flags & SLAB_RED_ZONE) memset(p - s->red_left_pad, val, s->red_left_pad); + if (slub_debug_orig_size(s) && val == SLUB_RED_ACTIVE) { + unsigned int zone_start; + + orig_size = get_orig_size(s, object); + zone_start = orig_size; + + if (!freeptr_outside_object(s)) + zone_start = max_t(unsigned int, orig_size, s->offset + sizeof(void *)); + + /* Redzone the allocated by kmalloc but unused space */ + if (zone_start < s->object_size) + memset(p + zone_start, val, s->object_size - zone_start); + } + if (s->flags & __OBJECT_POISON) { - memset(p, POISON_FREE, s->object_size - 1); - p[s->object_size - 1] = POISON_END; + memset(p, POISON_FREE, orig_size - 1); + p[orig_size - 1] = POISON_END; } if (s->flags & SLAB_RED_ZONE) @@ -1122,6 +1142,7 @@ static int check_object(struct kmem_cache *s, struct slab *slab, { u8 *p = object; u8 *endobject = object + s->object_size; + unsigned int orig_size; if (s->flags & SLAB_RED_ZONE) { if (!check_bytes_and_report(s, slab, object, "Left Redzone", @@ -1139,6 +1160,20 @@ static int check_object(struct kmem_cache *s, struct slab *slab, } } + if (slub_debug_orig_size(s) && val == SLUB_RED_ACTIVE) { + orig_size = get_orig_size(s, object); + + if (!freeptr_outside_object(s)) + orig_size = max_t(unsigned int, orig_size, + s->offset + sizeof(void *)); + if (s->object_size > orig_size && + !check_bytes_and_report(s, slab, object, + "kmalloc unused part", p + orig_size, + val, s->object_size - orig_size)) { + return 0; + } + } + if (s->flags & SLAB_POISON) { if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) && (!check_bytes_and_report(s, slab, p, "Poison", p, @@ -3287,7 +3322,7 @@ static __always_inline void *slab_alloc_node(struct kmem_cache *s, struct list_l init = slab_want_init_on_alloc(gfpflags, s); out: - slab_post_alloc_hook(s, objcg, gfpflags, 1, &object, init); + slab_post_alloc_hook(s, objcg, gfpflags, 1, &object, init, orig_size); return object; } @@ -3802,11 +3837,11 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, * Done outside of the IRQ disabled fastpath loop. */ slab_post_alloc_hook(s, objcg, flags, size, p, - slab_want_init_on_alloc(flags, s)); + slab_want_init_on_alloc(flags, s), 0); return i; error: slub_put_cpu_ptr(s->cpu_slab); - slab_post_alloc_hook(s, objcg, flags, i, p, false); + slab_post_alloc_hook(s, objcg, flags, i, p, false, 0); __kmem_cache_free_bulk(s, i, p); return 0; } @@ -4611,6 +4646,10 @@ size_t __ksize(const void *object) if (unlikely(!folio_test_slab(folio))) return folio_size(folio); +#ifdef CONFIG_SLUB_DEBUG + skip_orig_size_check(folio_slab(folio)->slab_cache, object); +#endif + return slab_ksize(folio_slab(folio)->slab_cache); } EXPORT_SYMBOL(__ksize);