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=-20.9 required=3.0 tests=BAYES_00,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_AGENT_GIT,USER_IN_DEF_DKIM_WL 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 EA39CC4742A for ; Tue, 29 Sep 2020 13:39:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 901602158C for ; Tue, 29 Sep 2020 13:39:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="P3GJtu0X" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729038AbgI2Ni5 (ORCPT ); Tue, 29 Sep 2020 09:38:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57272 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730001AbgI2Ni4 (ORCPT ); Tue, 29 Sep 2020 09:38:56 -0400 Received: from mail-wr1-x44a.google.com (mail-wr1-x44a.google.com [IPv6:2a00:1450:4864:20::44a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BD284C0613D4 for ; Tue, 29 Sep 2020 06:38:53 -0700 (PDT) Received: by mail-wr1-x44a.google.com with SMTP id v5so1796985wrr.0 for ; Tue, 29 Sep 2020 06:38:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to:cc; bh=RyhekuRkgmFAPj0MnrvGu5klxhimFNDAR1CWyJxk0no=; b=P3GJtu0X8/mJUA5wXsaUMq1f3Ji9qpURBWwQny9MQj/kaOKNiFCaVvpKqfv9QN5Oud NFMOrxdnTB5rI7v2QoRp/m4K+WVjB2ylGW1qPdBOArKXUnFJ5L6PoW/pkBh6PmXz/73W 8/7G7HQGFMyoeeNMMz6h1fJjhyHlhTLhyX6PU1aKQYN2GQWc2d3KINv4gZOdrE8BWj21 GJHchh4d2nVlPH1kVTeRffZXDH01afBmx1rUjt2Y00pfq5tNSgzRmPDv/aMpUFJoBVJq KIhJc862P6f+Xrydgg+lmi00K5DzKPH7jaBf9NDpA9uPWh1EN4SEZOamH3iMcjNFsIq+ 7RNQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=RyhekuRkgmFAPj0MnrvGu5klxhimFNDAR1CWyJxk0no=; b=Agh1aFvFHZfimC8E+dgghM8LzQuEN+aL0dgNlmA2ZLtzPnYP+CStSgwDie1tWuGgG0 p2V/QkuIxykRoO2gqLE70MC0JmuR1aK9ZqA9Jcb9rhRaLzC6ac6kJdv3VyVKUFWUHlBE SRGF+nSi/eLRsueA+aU7pAeucp8IPoWV4Z6/BRnFKbR/WZ0gjxFJsxGp7pE8IkDAk0Py o1MLzAIi3Q9pXiSHKEWTUNptVknI52eTu5qoBEZX7YpgFbX/AZuMe4/gIeKE0FUzCFAH sQVLBU+VAzuyFA13z/rsaNEza/iTKtNtaa1w2xYj3/o+RTnWsYqHBcWidvb6/+BSk95K /aig== X-Gm-Message-State: AOAM530F9sT2dHYCMwr3ldr3vqXTFMpjSYSF/sWaA8qGaEI/K/D7DDL+ CDk/ouLuntMddo9NymuSrrnh02HZUw== X-Google-Smtp-Source: ABdhPJyuDC6Gatzso3JgB/J1LMf7YqlN6iUJcX8/Pa/jxmUp8L+nE4LsQMXIprQXcHL1CT+Uty9p2pRwgA== Sender: "elver via sendgmr" X-Received: from elver.muc.corp.google.com ([2a00:79e0:15:13:f693:9fff:fef4:2449]) (user=elver job=sendgmr) by 2002:a7b:c453:: with SMTP id l19mr4414928wmi.163.1601386732135; Tue, 29 Sep 2020 06:38:52 -0700 (PDT) Date: Tue, 29 Sep 2020 15:38:07 +0200 In-Reply-To: <20200929133814.2834621-1-elver@google.com> Message-Id: <20200929133814.2834621-5-elver@google.com> Mime-Version: 1.0 References: <20200929133814.2834621-1-elver@google.com> X-Mailer: git-send-email 2.28.0.709.gb0816b6eb0-goog Subject: [PATCH v4 04/11] mm, kfence: insert KFENCE hooks for SLAB From: Marco Elver To: elver@google.com, akpm@linux-foundation.org, glider@google.com Cc: hpa@zytor.com, paulmck@kernel.org, andreyknvl@google.com, aryabinin@virtuozzo.com, luto@kernel.org, bp@alien8.de, catalin.marinas@arm.com, cl@linux.com, dave.hansen@linux.intel.com, rientjes@google.com, dvyukov@google.com, edumazet@google.com, gregkh@linuxfoundation.org, hdanton@sina.com, mingo@redhat.com, jannh@google.com, Jonathan.Cameron@huawei.com, corbet@lwn.net, iamjoonsoo.kim@lge.com, keescook@chromium.org, mark.rutland@arm.com, penberg@kernel.org, peterz@infradead.org, sjpark@amazon.com, tglx@linutronix.de, vbabka@suse.cz, will@kernel.org, x86@kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org From: Alexander Potapenko Inserts KFENCE hooks into the SLAB allocator. To pass the originally requested size to KFENCE, add an argument 'orig_size' to slab_alloc*(). The additional argument is required to preserve the requested original size for kmalloc() allocations, which uses size classes (e.g. an allocation of 272 bytes will return an object of size 512). Therefore, kmem_cache::size does not represent the kmalloc-caller's requested size, and we must introduce the argument 'orig_size' to propagate the originally requested size to KFENCE. Without the originally requested size, we would not be able to detect out-of-bounds accesses for objects placed at the end of a KFENCE object page if that object is not equal to the kmalloc-size class it was bucketed into. When KFENCE is disabled, there is no additional overhead, since slab_alloc*() functions are __always_inline. Reviewed-by: Dmitry Vyukov Co-developed-by: Marco Elver Signed-off-by: Marco Elver Signed-off-by: Alexander Potapenko --- v3: * Rewrite patch description to clarify need for 'orig_size' [reported by Christopher Lameter]. --- mm/slab.c | 46 ++++++++++++++++++++++++++++++++++------------ mm/slab_common.c | 6 +++++- 2 files changed, 39 insertions(+), 13 deletions(-) diff --git a/mm/slab.c b/mm/slab.c index 3160dff6fd76..30aba06ae02b 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -100,6 +100,7 @@ #include #include #include +#include #include #include #include @@ -3206,7 +3207,7 @@ static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, } static __always_inline void * -slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid, +slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid, size_t orig_size, unsigned long caller) { unsigned long save_flags; @@ -3219,6 +3220,10 @@ slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid, if (unlikely(!cachep)) return NULL; + ptr = kfence_alloc(cachep, orig_size, flags); + if (unlikely(ptr)) + goto out_hooks; + cache_alloc_debugcheck_before(cachep, flags); local_irq_save(save_flags); @@ -3251,6 +3256,7 @@ slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid, if (unlikely(slab_want_init_on_alloc(flags, cachep)) && ptr) memset(ptr, 0, cachep->object_size); +out_hooks: slab_post_alloc_hook(cachep, objcg, flags, 1, &ptr); return ptr; } @@ -3288,7 +3294,7 @@ __do_cache_alloc(struct kmem_cache *cachep, gfp_t flags) #endif /* CONFIG_NUMA */ static __always_inline void * -slab_alloc(struct kmem_cache *cachep, gfp_t flags, unsigned long caller) +slab_alloc(struct kmem_cache *cachep, gfp_t flags, size_t orig_size, unsigned long caller) { unsigned long save_flags; void *objp; @@ -3299,6 +3305,10 @@ slab_alloc(struct kmem_cache *cachep, gfp_t flags, unsigned long caller) if (unlikely(!cachep)) return NULL; + objp = kfence_alloc(cachep, orig_size, flags); + if (unlikely(objp)) + goto leave; + cache_alloc_debugcheck_before(cachep, flags); local_irq_save(save_flags); objp = __do_cache_alloc(cachep, flags); @@ -3309,6 +3319,7 @@ slab_alloc(struct kmem_cache *cachep, gfp_t flags, unsigned long caller) if (unlikely(slab_want_init_on_alloc(flags, cachep)) && objp) memset(objp, 0, cachep->object_size); +leave: slab_post_alloc_hook(cachep, objcg, flags, 1, &objp); return objp; } @@ -3414,6 +3425,11 @@ static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac) static __always_inline void __cache_free(struct kmem_cache *cachep, void *objp, unsigned long caller) { + if (kfence_free(objp)) { + kmemleak_free_recursive(objp, cachep->flags); + return; + } + /* Put the object into the quarantine, don't touch it for now. */ if (kasan_slab_free(cachep, objp, _RET_IP_)) return; @@ -3479,7 +3495,7 @@ void ___cache_free(struct kmem_cache *cachep, void *objp, */ void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags) { - void *ret = slab_alloc(cachep, flags, _RET_IP_); + void *ret = slab_alloc(cachep, flags, cachep->object_size, _RET_IP_); trace_kmem_cache_alloc(_RET_IP_, ret, cachep->object_size, cachep->size, flags); @@ -3512,7 +3528,7 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, local_irq_disable(); for (i = 0; i < size; i++) { - void *objp = __do_cache_alloc(s, flags); + void *objp = kfence_alloc(s, s->object_size, flags) ?: __do_cache_alloc(s, flags); if (unlikely(!objp)) goto error; @@ -3545,7 +3561,7 @@ kmem_cache_alloc_trace(struct kmem_cache *cachep, gfp_t flags, size_t size) { void *ret; - ret = slab_alloc(cachep, flags, _RET_IP_); + ret = slab_alloc(cachep, flags, size, _RET_IP_); ret = kasan_kmalloc(cachep, ret, size, flags); trace_kmalloc(_RET_IP_, ret, @@ -3571,7 +3587,7 @@ EXPORT_SYMBOL(kmem_cache_alloc_trace); */ void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid) { - void *ret = slab_alloc_node(cachep, flags, nodeid, _RET_IP_); + void *ret = slab_alloc_node(cachep, flags, nodeid, cachep->object_size, _RET_IP_); trace_kmem_cache_alloc_node(_RET_IP_, ret, cachep->object_size, cachep->size, @@ -3589,7 +3605,7 @@ void *kmem_cache_alloc_node_trace(struct kmem_cache *cachep, { void *ret; - ret = slab_alloc_node(cachep, flags, nodeid, _RET_IP_); + ret = slab_alloc_node(cachep, flags, nodeid, size, _RET_IP_); ret = kasan_kmalloc(cachep, ret, size, flags); trace_kmalloc_node(_RET_IP_, ret, @@ -3650,7 +3666,7 @@ static __always_inline void *__do_kmalloc(size_t size, gfp_t flags, cachep = kmalloc_slab(size, flags); if (unlikely(ZERO_OR_NULL_PTR(cachep))) return cachep; - ret = slab_alloc(cachep, flags, caller); + ret = slab_alloc(cachep, flags, size, caller); ret = kasan_kmalloc(cachep, ret, size, flags); trace_kmalloc(caller, ret, @@ -4138,18 +4154,24 @@ void __check_heap_object(const void *ptr, unsigned long n, struct page *page, bool to_user) { struct kmem_cache *cachep; - unsigned int objnr; + unsigned int objnr = 0; unsigned long offset; + bool is_kfence = is_kfence_address(ptr); ptr = kasan_reset_tag(ptr); /* Find and validate object. */ cachep = page->slab_cache; - objnr = obj_to_index(cachep, page, (void *)ptr); - BUG_ON(objnr >= cachep->num); + if (!is_kfence) { + objnr = obj_to_index(cachep, page, (void *)ptr); + BUG_ON(objnr >= cachep->num); + } /* Find offset within object. */ - offset = ptr - index_to_obj(cachep, page, objnr) - obj_offset(cachep); + if (is_kfence_address(ptr)) + offset = ptr - kfence_object_start(ptr); + else + offset = ptr - index_to_obj(cachep, page, objnr) - obj_offset(cachep); /* Allow address range falling entirely within usercopy region. */ if (offset >= cachep->useroffset && diff --git a/mm/slab_common.c b/mm/slab_common.c index f9ccd5dc13f3..6e35e273681a 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include #include @@ -448,6 +449,9 @@ static int shutdown_cache(struct kmem_cache *s) /* free asan quarantined objects */ kasan_cache_shutdown(s); + if (!kfence_shutdown_cache(s)) + return -EBUSY; + if (__kmem_cache_shutdown(s) != 0) return -EBUSY; @@ -1171,7 +1175,7 @@ size_t ksize(const void *objp) if (unlikely(ZERO_OR_NULL_PTR(objp)) || !__kasan_check_read(objp, 1)) return 0; - size = __ksize(objp); + size = kfence_ksize(objp) ?: __ksize(objp); /* * We assume that ksize callers could use whole allocated area, * so we need to unpoison this area. -- 2.28.0.709.gb0816b6eb0-goog