From nobody Sun Dec 14 21:52:57 2025 Received: from mail-wm1-f51.google.com (mail-wm1-f51.google.com [209.85.128.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A38A32652B6 for ; Thu, 4 Dec 2025 14:13:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.51 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764857587; cv=none; b=Wv8rxeIStbWqvNY5W6l+LluIrhEI8RKRfFb5UGxM8IxNdlb3eCjKzk36qIiLYeN1theBdIorunYNFlWXXFIC12v7djEgT0wHrzTw8CrKKljeqJt2MSe+eSzxF2Xet6HX35tAu9CKH9zaNLcx/wlGhqCp8FRVOXeQvg5BsqUx5gk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764857587; c=relaxed/simple; bh=sPmkDEwwPWrQdJRXFfdzLMoaCivv4pvJuP/ZwzlRc98=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=TQOqduxyqHd7r3shmv4zIpRuHD7uiJ8YstcLbzb/3EZLzOFHBZOF59Tkh8aehVTqc8pmj0UFyARMvMEsYljvvIYy9QAzJSf6SdrOODQtP2SePgAE4zeoJOP4uOFLalpNTMjRbf+e9+A2ZaX5KjCZFifnfOoIWbz6C719iLTomBw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=JuDUMbTz; arc=none smtp.client-ip=209.85.128.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="JuDUMbTz" Received: by mail-wm1-f51.google.com with SMTP id 5b1f17b1804b1-477b1cc8fb4so6997595e9.1 for ; Thu, 04 Dec 2025 06:13:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1764857584; x=1765462384; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=vvLRPmFVeFXL/FXUoH0yHVRGEwWvQKNGaG9SkVtG73M=; b=JuDUMbTzRHg7EtYfYyfkGNC26E1gxHm3E+RnhS1qsH67E4NPZKcNIx4NJXsUJNnzO5 Z2AjIbuR5Gdf7Mh7d/gRhHwtglZCd3KgJ5dK9cjnWX5nuA0FaxkwDeF0Y+9KGSIPmQ03 Opt5PyrRpDji3+3ynvgaRG04Po2LHlmCJSb1YJ57ua4lSwBUUX1Lv6Ovxk+VRNMTJyjP ze5X0L6KMgFOcj44j8QgAtik7whmf/8IpK2lH5Y9Rz/R2+YXAsmy8klt7roE2EOW9axH cY87Brt8LYuOHYukS3yy/QdBZsOnzHc7U9at16L86H+TVCZd78tbzcsEQGIi5KAM+Mw2 YnuQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1764857584; x=1765462384; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=vvLRPmFVeFXL/FXUoH0yHVRGEwWvQKNGaG9SkVtG73M=; b=Oxo3+JP4UYaKuT/qdQD61Gmu82QTpYdb53sS9DQQ7dyXhfBVyzDYO05VT+MdGiK+2V aItISY7mOVn971sCzlEdWPXYjcPFfnGPbwxxHDG63L/ksassvqs7W2alm7JgbuKGNSTk xpdfPv4y+Z+GcIpN1gOT9pflezVQapqm/S4F06+v+YUrpO/HEPLZXQYfsGuqGBvsG+Vr Y2KR2eeJpPOtZ4gi9KYXET+czH+1occBpQ2YcWXvXC7xWivVHE2H7NTdGwJ6E3x+xKMy 88oM945B+V3mfTd81dBBhY5rf80mS+gDphnRREO/H7qN3TuSmVKansMwwDcm27snoRtO UlHg== X-Forwarded-Encrypted: i=1; AJvYcCX1NHwTpZN5PSEvonSvMUhq4ukcRPlqMlJh+luqGLqEVYh1BThsiPtYeWO76jQPYS2mEwfofIo4mQ7lSNE=@vger.kernel.org X-Gm-Message-State: AOJu0YxIRcOArcc5Rle/rKZPmixwPFgkRtbiLWKYjTFUizsihwBGpPdQ xa8QLWFMXzyK7CaQTterI0BzkfvikMyRWhuti7meRUrYdGS2QxT4W5qc X-Gm-Gg: ASbGnctQUQ97Y+Ugtbba/qZdq9Xe7eRwakphcwmCGuHsixuN/GDGvYfzebVlFKSccBy 6tr5swHwoifJ71wRbgFbpGgtVb2xnSGcVPVEL/GEjSwXqV/zXryxv44k04vSMcHncLRK8QnmLuL VnIfHOVJWQiZxp/PiAvjjtWwZoC0DotDYDnJeAIO1J/eGoaKat4j5KmMxfPPCa6DGwX4RRNSaXu kX/RnnneYu6PHYVEIaBWlVBB2LE7wKsMaIW6EI0wx64i/0BhPRXPze8BE5vvp6Vr9A24tIN+hcY Oe+cYtAQFAkYA50pKUNQ2r8QusU36MrPSdxWuooHjtcFAEyppI1Xqb01YsPQXdTiWDl5ru5+YgQ KJsSb8GhGr5S12EbZw8e+tmieTji0okN/eaR3SBu4aY7Isz2bmEdge5e6fiXxGY8uYWyOO8XiPV +Xwv+LuepiW/4DrbG/9yOCQH+gN8/R2qKFQ5936ae+pVKZVFkbL7C8rQMg8+iobQ2Vpw== X-Google-Smtp-Source: AGHT+IHVRlhcJRejGEsgP4K4cLss0ObE1mVBCmN6UHr1S399d5qS3NN/eNqDmcGxbLusiL5cPl9foQ== X-Received: by 2002:a05:600c:3545:b0:46e:74cc:42b8 with SMTP id 5b1f17b1804b1-4792f3860e4mr28572475e9.17.1764857583596; Thu, 04 Dec 2025 06:13:03 -0800 (PST) Received: from ethan-tp.d.ethz.ch (2001-67c-10ec-5744-8000--626.net6.ethz.ch. [2001:67c:10ec:5744:8000::626]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-42f7cbfeae9sm3605808f8f.13.2025.12.04.06.13.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 04 Dec 2025 06:13:03 -0800 (PST) From: Ethan Graham To: ethan.w.s.graham@gmail.com, glider@google.com Cc: andreyknvl@gmail.com, andy@kernel.org, andy.shevchenko@gmail.com, brauner@kernel.org, brendan.higgins@linux.dev, davem@davemloft.net, davidgow@google.com, dhowells@redhat.com, dvyukov@google.com, elver@google.com, herbert@gondor.apana.org.au, ignat@cloudflare.com, jack@suse.cz, jannh@google.com, johannes@sipsolutions.net, kasan-dev@googlegroups.com, kees@kernel.org, kunit-dev@googlegroups.com, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, lukas@wunner.de, rmoar@google.com, shuah@kernel.org, sj@kernel.org, tarasmadan@google.com, Ethan Graham Subject: [PATCH 01/10] mm/kasan: implement kasan_poison_range Date: Thu, 4 Dec 2025 15:12:40 +0100 Message-ID: <20251204141250.21114-2-ethan.w.s.graham@gmail.com> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251204141250.21114-1-ethan.w.s.graham@gmail.com> References: <20251204141250.21114-1-ethan.w.s.graham@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Ethan Graham Introduce a new helper function, kasan_poison_range(), to encapsulate the logic for poisoning an arbitrary memory range of a given size, and expose it publically in . This is a preparatory change for the upcoming KFuzzTest patches, which requires the ability to poison the inter-region padding in its input buffers. No functional change to any other subsystem is intended by this commit. Signed-off-by: Ethan Graham Signed-off-by: Ethan Graham Reviewed-by: Alexander Potapenko --- PR v3: - Move kasan_poison_range into mm/kasan/common.c so that it is built with HW_TAGS mode enabled. - Add a runtime check for kasan_enabled() in kasan_poison_range. - Add two WARN_ON()s in kasan_poison_range when the input is invalid. PR v1: - Enforce KASAN_GRANULE_SIZE alignment for the end of the range in kasan_poison_range(), and return -EINVAL when this isn't respected. --- --- include/linux/kasan.h | 11 +++++++++++ mm/kasan/common.c | 37 +++++++++++++++++++++++++++++++++++++ 2 files changed, 48 insertions(+) diff --git a/include/linux/kasan.h b/include/linux/kasan.h index 890011071f2b..cd6cdf732378 100644 --- a/include/linux/kasan.h +++ b/include/linux/kasan.h @@ -102,6 +102,16 @@ static inline bool kasan_has_integrated_init(void) } =20 #ifdef CONFIG_KASAN + +/** + * kasan_poison_range - poison the memory range [@addr, @addr + @size) + * + * The exact behavior is subject to alignment with KASAN_GRANULE_SIZE, def= ined + * in : if @start is unaligned, the initial partial gran= ule + * at the beginning of the range is only poisoned if CONFIG_KASAN_GENERIC= =3Dy. + */ +int kasan_poison_range(const void *addr, size_t size); + void __kasan_unpoison_range(const void *addr, size_t size); static __always_inline void kasan_unpoison_range(const void *addr, size_t = size) { @@ -402,6 +412,7 @@ static __always_inline bool kasan_check_byte(const void= *addr) =20 #else /* CONFIG_KASAN */ =20 +static inline int kasan_poison_range(const void *start, size_t size) { ret= urn 0; } static inline void kasan_unpoison_range(const void *address, size_t size) = {} static inline void kasan_poison_pages(struct page *page, unsigned int orde= r, bool init) {} diff --git a/mm/kasan/common.c b/mm/kasan/common.c index 9142964ab9c9..c83579ef37c6 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -570,3 +570,40 @@ bool __kasan_check_byte(const void *address, unsigned = long ip) } return true; } + +int kasan_poison_range(const void *addr, size_t size) +{ + uintptr_t start_addr =3D (uintptr_t)addr; + uintptr_t head_granule_start; + uintptr_t poison_body_start; + uintptr_t poison_body_end; + size_t head_prefix_size; + uintptr_t end_addr; + + if (!kasan_enabled()) + return 0; + + end_addr =3D start_addr + size; + if (WARN_ON(end_addr % KASAN_GRANULE_SIZE)) + return -EINVAL; + + if (WARN_ON(start_addr >=3D end_addr)) + return -EINVAL; + + head_granule_start =3D ALIGN_DOWN(start_addr, KASAN_GRANULE_SIZE); + head_prefix_size =3D start_addr - head_granule_start; + + if (IS_ENABLED(CONFIG_KASAN_GENERIC) && head_prefix_size > 0) + kasan_poison_last_granule((void *)head_granule_start, + head_prefix_size); + + poison_body_start =3D ALIGN(start_addr, KASAN_GRANULE_SIZE); + poison_body_end =3D end_addr; + + if (poison_body_start < poison_body_end) + kasan_poison((void *)poison_body_start, + poison_body_end - poison_body_start, + KASAN_SLAB_REDZONE, false); + return 0; +} +EXPORT_SYMBOL(kasan_poison_range); --=20 2.51.0