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=-13.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_RED autolearn=ham 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 A7D41C4743C for ; Mon, 21 Jun 2021 13:06:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8E7BB600D4 for ; Mon, 21 Jun 2021 13:06:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229804AbhFUNJA (ORCPT ); Mon, 21 Jun 2021 09:09:00 -0400 Received: from forward2-smtp.messagingengine.com ([66.111.4.226]:54355 "EHLO forward2-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229699AbhFUNI7 (ORCPT ); Mon, 21 Jun 2021 09:08:59 -0400 Received: from compute6.internal (compute6.nyi.internal [10.202.2.46]) by mailforward.nyi.internal (Postfix) with ESMTP id 72ACA1940680; Mon, 21 Jun 2021 09:06:45 -0400 (EDT) Received: from mailfrontend2 ([10.202.2.163]) by compute6.internal (MEProxy); Mon, 21 Jun 2021 09:06:45 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:content-type :date:from:message-id:mime-version:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm3; bh=8uVIUb mWP9rVNqsyTlw7q5/wOgaiSBIGoy4mM58JmMc=; b=HDXhMxSCx00UWVXQSI/ov/ ZoPNg8B5pHuaaVWnX0bhiPvI5+aWarPKOx/ddbJxsxFFjgVYEfYf0zSUM3ROJ8WR Gnf1Km4LJTo7SUDSEs85VPu3m42awipO06zpgYPHNIu40Hk9iuRgiet9BLWU0t3G ID9rf23005JtILUcS5D1wPTRfTqk8zUoGEJRiviTdUQ7MQ+h6qvLOLwX/kcmyxR1 DQQ6/H5qhEBF2BI5xTDyMmNdkzwPymJ7mUKEmZzvAkakaPvyj8i9IpgMirnYaQir e5l/rqVlUnK5sWVjZZ/dHlPJdGVPSyjwL4IbocM3xwg6/kzj1Qdl3rdg6ejoekyA == X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduledrfeefledgiedtucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucenucfjughrpefuvffhfffkgggtgfesthekredttd dtlfenucfhrhhomhepoehgrhgvghhkhheslhhinhhugihfohhunhgurghtihhonhdrohhr gheqnecuggftrfgrthhtvghrnhepleelledvgeefleeltdetgedugeffgffhudffudduke egfeelgeeigeekjefhleevnecuffhomhgrihhnpehkvghrnhgvlhdrohhrghenucevlhhu shhtvghrufhiiigvpedunecurfgrrhgrmhepmhgrihhlfhhrohhmpehgrhgvgheskhhroh grhhdrtghomh X-ME-Proxy: Received: by mail.messagingengine.com (Postfix) with ESMTPA; Mon, 21 Jun 2021 09:06:43 -0400 (EDT) Subject: FAILED: patch "[PATCH] mm/slub: actually fix freelist pointer vs redzoning" failed to apply to 5.4-stable tree To: keescook@chromium.org, akpm@linux-foundation.org, cl@linux.com, elver@google.com, guro@fb.com, iamjoonsoo.kim@lge.com, penberg@kernel.org, rientjes@google.com, stable@vger.kernel.org, torvalds@linux-foundation.org, vbabka@suse.cz, zplin@psu.edu Cc: From: Date: Mon, 21 Jun 2021 15:06:34 +0200 Message-ID: <162428079422629@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From e41a49fadbc80b60b48d3c095d9e2ee7ef7c9a8e Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Tue, 15 Jun 2021 18:23:26 -0700 Subject: [PATCH] mm/slub: actually fix freelist pointer vs redzoning It turns out that SLUB redzoning ("slub_debug=Z") checks from s->object_size rather than from s->inuse (which is normally bumped to make room for the freelist pointer), so a cache created with an object size less than 24 would have the freelist pointer written beyond s->object_size, causing the redzone to be corrupted by the freelist pointer. This was very visible with "slub_debug=ZF": BUG test (Tainted: G B ): Right Redzone overwritten ----------------------------------------------------------------------------- INFO: 0xffff957ead1c05de-0xffff957ead1c05df @offset=1502. First byte 0x1a instead of 0xbb INFO: Slab 0xffffef3950b47000 objects=170 used=170 fp=0x0000000000000000 flags=0x8000000000000200 INFO: Object 0xffff957ead1c05d8 @offset=1496 fp=0xffff957ead1c0620 Redzone (____ptrval____): bb bb bb bb bb bb bb bb ........ Object (____ptrval____): 00 00 00 00 00 f6 f4 a5 ........ Redzone (____ptrval____): 40 1d e8 1a aa @.... Padding (____ptrval____): 00 00 00 00 00 00 00 00 ........ Adjust the offset to stay within s->object_size. (Note that no caches of in this size range are known to exist in the kernel currently.) Link: https://lkml.kernel.org/r/20210608183955.280836-4-keescook@chromium.org Link: https://lore.kernel.org/linux-mm/20200807160627.GA1420741@elver.google.com/ Link: https://lore.kernel.org/lkml/0f7dd7b2-7496-5e2d-9488-2ec9f8e90441@suse.cz/Fixes: 89b83f282d8b (slub: avoid redzone when choosing freepointer location) Link: https://lore.kernel.org/lkml/CANpmjNOwZ5VpKQn+SYWovTkFB4VsT-RPwyENBmaK0dLcpqStkA@mail.gmail.com Signed-off-by: Kees Cook Reported-by: Marco Elver Reported-by: "Lin, Zhenpeng" Tested-by: Marco Elver Acked-by: Vlastimil Babka Cc: Christoph Lameter Cc: David Rientjes Cc: Joonsoo Kim Cc: Pekka Enberg Cc: Roman Gushchin Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds diff --git a/mm/slub.c b/mm/slub.c index f58cfd456548..fe30df460fad 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -3689,7 +3689,6 @@ static int calculate_sizes(struct kmem_cache *s, int forced_order) { slab_flags_t flags = s->flags; unsigned int size = s->object_size; - unsigned int freepointer_area; unsigned int order; /* @@ -3698,13 +3697,6 @@ static int calculate_sizes(struct kmem_cache *s, int forced_order) * the possible location of the free pointer. */ size = ALIGN(size, sizeof(void *)); - /* - * This is the area of the object where a freepointer can be - * safely written. If redzoning adds more to the inuse size, we - * can't use that portion for writing the freepointer, so - * s->offset must be limited within this for the general case. - */ - freepointer_area = size; #ifdef CONFIG_SLUB_DEBUG /* @@ -3730,7 +3722,7 @@ static int calculate_sizes(struct kmem_cache *s, int forced_order) /* * With that we have determined the number of bytes in actual use - * by the object. This is the potential offset to the free pointer. + * by the object and redzoning. */ s->inuse = size; @@ -3753,13 +3745,13 @@ static int calculate_sizes(struct kmem_cache *s, int forced_order) */ s->offset = size; size += sizeof(void *); - } else if (freepointer_area > sizeof(void *)) { + } else { /* * Store freelist pointer near middle of object to keep * it away from the edges of the object to avoid small * sized over/underflows from neighboring allocations. */ - s->offset = ALIGN(freepointer_area / 2, sizeof(void *)); + s->offset = ALIGN_DOWN(s->object_size / 2, sizeof(void *)); } #ifdef CONFIG_SLUB_DEBUG