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([103.230.148.188]) by smtp.gmail.com with ESMTPSA id ms3-20020a17090b234300b001ead46e77e2sm5450642pjb.13.2022.06.26.10.04.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 26 Jun 2022 10:04:18 -0700 (PDT) From: Gautam Menghani To: ryabinin.a.a@gmail.com, glider@google.com, andreyknvl@gmail.com, dvyukov@google.com, vincenzo.frascino@arm.com, akpm@linux-foundation.org Cc: Gautam Menghani , kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, skhan@linuxfoundation.org Subject: [PATCH] mm/kasan: Fix null pointer dereference warning in qlink_to_cache() Date: Sun, 26 Jun 2022 22:33:55 +0530 Message-Id: <20220626170355.198913-1-gautammenghani201@gmail.com> X-Mailer: git-send-email 2.36.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1656263061; 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:references:dkim-signature; bh=oFSj1F+cvrzuMgRbVJtsNeMg49O8qOKUhwSEI2b4t3A=; b=ixh+LrBmvXlICPKpuZ6sVyBS1UjBQ+URlectzHBZ7mLzqCGAt0sBchVUQPLkcDWqz66Wph /BN9vCEiTZ4guIGBPP6M/yotSVsBphQyvYZURoVDSCj6Ow81bzLNlTeHv7ML9lMHYMnjcG +25Um8AD6/ZbgRWxAZ+rVNJfzDfUbQU= ARC-Authentication-Results: i=1; imf25.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=AAAVJXiW; spf=pass (imf25.hostedemail.com: domain of gautammenghani201@gmail.com designates 209.85.216.43 as permitted sender) smtp.mailfrom=gautammenghani201@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1656263061; a=rsa-sha256; cv=none; b=rIONC0ntY9Jl5780YzfvPMEJ7WkrF8Vkb4jg+JFq200XTo2rvYwuvIQeVFmXsfIMaGNrYS j1b0vRwf/yMHnCGp6HZtxbdwr48VHduGrPaogIY3oagugt5Oqfu80j46jFc9l4/3gVj9WD TbkrEfwBvBPQk4ebDH0L98vuO+TJl4s= Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=AAAVJXiW; spf=pass (imf25.hostedemail.com: domain of gautammenghani201@gmail.com designates 209.85.216.43 as permitted sender) smtp.mailfrom=gautammenghani201@gmail.com; dmarc=pass (policy=none) header.from=gmail.com X-Rspam-User: X-Rspamd-Server: rspam06 X-Stat-Signature: de1n3whszq93xu9qmxi8bxhnwtyf1qhn X-Rspamd-Queue-Id: 08082A0027 X-HE-Tag: 1656263060-793676 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: The function virt_to_slab() declared in slab.h can return NULL if the address does not belong to a slab. This case is not handled in the function qlink_to_cache() in the file quarantine.c, which can cause a NULL pointer dereference in "virt_to_slab(qlink)->slab_cache". This issue was discovered by fanalyzer (my gcc version: 12.1.1 20220507) Signed-off-by: Gautam Menghani --- mm/kasan/quarantine.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c index 75585077eb6d..c7554f5b9fb6 100644 --- a/mm/kasan/quarantine.c +++ b/mm/kasan/quarantine.c @@ -128,7 +128,13 @@ static unsigned long quarantine_batch_size; static struct kmem_cache *qlink_to_cache(struct qlist_node *qlink) { - return virt_to_slab(qlink)->slab_cache; + struct slab *folio_slab = virt_to_slab(qlink); + + if (!folio_slab) { + pr_warn("The address %p does not belong to a slab", qlink); + return NULL; + } + return folio_slab->slab_cache; } static void *qlink_to_object(struct qlist_node *qlink, struct kmem_cache *cache) -- 2.36.1