From nobody Thu Oct 2 15:34:43 2025 Received: from mail-wm1-f41.google.com (mail-wm1-f41.google.com [209.85.128.41]) (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 8ADD7213E6A for ; Tue, 16 Sep 2025 09:01:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.41 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758013283; cv=none; b=XvboLE+gebKCBWCkmhZZIK0782wohoEeQ7LWFv46LhZ6GNgQuJc+usnQRkVxAr/gCPPCvFbbeL5VdFvUq6BQBTb2BOiJw+6Jez1Luaot+g4O45jDKWgm20Grhz25SZSR72nD94lJSMKNu9zta3I0ETkuO8uFG+O5GkmnByDg2qg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758013283; c=relaxed/simple; bh=qJDnwsi8rYP5Wp+H8LxkPOvT+aBCJa1jnIBCRmNCEj4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Hbt8YLTeVbIL5CfjQye2VSySfN97Pm3yrElgU/vkXL1v89gGqS3gNDt3RXi+r24AArIlO4nf2N85VA+MZYuMOI/ZTD8Cxk7EA45/Zb1zer2JhlulqRr1KMOObDmCLrbrwsNTeqlON4AROFvXIXAufBsOVufOGeMg7bXWCh1fWnk= 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=AbjscKHF; arc=none smtp.client-ip=209.85.128.41 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="AbjscKHF" Received: by mail-wm1-f41.google.com with SMTP id 5b1f17b1804b1-45f2b062b86so15316275e9.1 for ; Tue, 16 Sep 2025 02:01:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1758013280; x=1758618080; 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=2yrCmffzlGuEExOPu+2JuPwFc40pU2sHK0rUuIT3g74=; b=AbjscKHFL8ivpiE4yWO+py7ajRN2ClTsfiDFIRjyAWoo9kIt4V+jaLQmEtXoTMVOoU rrt8EjbnVxENPm5Fi2UHy3/PUzGC3BUeNun/bglZzVRhHIOPWHgmgBIaHl06VqL4S4Rm aPtBklFN924h2JgG7ULc8v5G4BNM+BPurRoQ2azY6NBh+CFMD0rbNoa+FPXInbSZPRZe T+DxzhyzxzX9y4nlWTB4nH/tfnphWTV+1VhiJs5kI3szySOS+f3870jwMy/DKI4YCWb3 9QL2EzjFAb2cQc8SIMZ6rKixzpInrUj/aNN+Hh5csqoziUUtZeLgijcFRrKXSeS8KGmc dtQw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1758013280; x=1758618080; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=2yrCmffzlGuEExOPu+2JuPwFc40pU2sHK0rUuIT3g74=; b=GbiJX/2Bm2HW2k4Hqg/F0DI8+cAnbQGocRsBjuW42rPtfo7LSJHxBfrTqGxXLQ4psf 7zpKIpdvZEpE9lZ70L8rgaNIZVh/P5JZEDHSwoL2CTHtIvJqO0pOKao57RFOIDv8dE1T ha6OpHsqQlWN+bNty9w1d00dg4lZYDGBU7THI3BRffonxDh+IPL6YC6dLjUo7bvd4s6K vkEpsZRGd0ZXziFYWa27Dbltp83mYOpZQiai49KAlccATHR3tQzy7nkR8R+r8guBqCw8 /zoW5WK+ypBMnZX+Sc8/LgtcG30/k1h2DUkA/K3wbhZkRrMBXcetVqxCPOOrbPDbM3LT Sf7g== X-Forwarded-Encrypted: i=1; AJvYcCXlK07LO9LtsODD8Jurb2XoWL3qgkkrTTWnBext2mExmJWZaNvcj7DFakuKewx/xLWtPG9VIGa7lWixx9E=@vger.kernel.org X-Gm-Message-State: AOJu0Yw3pIkm+T1+chsEgeY0nhVXZSbGdnUihYjYyJvujrmeXXs0lW4Q lDvx0zKmlE0RSN6coSre9lxzbPGAHweAlyUlvK22Jt56RD2ml6lq01x9 X-Gm-Gg: ASbGncsYt1KU1bf1SFZ0w8YLS/8ZwzAIiNDQVF5Si4abDT3r5VsXoNlGQzEw3/t3Sjp hOxX5TxEl/PrqwlTgA7V0TdmIHunccT18bXAxp+BeWkRlj6H4ReY9Znzpd6sUN115lobeKq/Fgd OV1hXhFRwcReIfhie42EXs6BEbNoFvrUSWkHljIhSYfJ+iT9moISVl2KWqpkLJ4/33wQqVTqbcK gppfwWkD/Pi1L6FDCPpJoEX3EXzan4ttpoQJVlFjL6nwBvSyOvGUQz/J0ZgXevS8/kdAZVSrwgV aPamiwrDg0lPAOMUMZ+gywkt9vIucnQSjVp6nV9LgCCe4pQx6DuQio09/XfK2YtZdBd/XCOOcNl rqjDZcO0cjdpThkGsZmWYhlnZ7wmCdWujtQc57/om6KMEyHxsVeMwwiH4aGtzP+9dTg2tE87736 RGLItQCs2/+JyDUadJojnspHM= X-Google-Smtp-Source: AGHT+IG5iZ2HWUjjmWFwCC/GHnLa6bpp4pAlSd7iyIhSqBHOTc39tKRs7gflZ9w5k6y0UE7LS5O+zA== X-Received: by 2002:a05:6000:250e:b0:3ec:d789:b35e with SMTP id ffacd0b85a97d-3ecd789b5b1mr817634f8f.8.1758013279529; Tue, 16 Sep 2025 02:01:19 -0700 (PDT) Received: from xl-nested.c.googlers.com.com (42.16.79.34.bc.googleusercontent.com. [34.79.16.42]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-45e037186e5sm212975035e9.5.2025.09.16.02.01.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 16 Sep 2025 02:01:18 -0700 (PDT) From: Ethan Graham To: ethangraham@google.com, glider@google.com Cc: andreyknvl@gmail.com, andy@kernel.org, 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, tarasmadan@google.com Subject: [PATCH v1 01/10] mm/kasan: implement kasan_poison_range Date: Tue, 16 Sep 2025 09:01:00 +0000 Message-ID: <20250916090109.91132-2-ethan.w.s.graham@gmail.com> X-Mailer: git-send-email 2.51.0.384.g4c02a37b29-goog In-Reply-To: <20250916090109.91132-1-ethan.w.s.graham@gmail.com> References: <20250916090109.91132-1-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. Reviewed-by: Alexander Potapenko --- v3: - Enforce KASAN_GRANULE_SIZE alignment for the end of the range in kasan_poison_range(), and return -EINVAL when this isn't respected. --- Signed-off-by: Ethan Graham --- include/linux/kasan.h | 11 +++++++++++ mm/kasan/shadow.c | 34 ++++++++++++++++++++++++++++++++++ 2 files changed, 45 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/shadow.c b/mm/kasan/shadow.c index d2c70cd2afb1..7faed02264f2 100644 --- a/mm/kasan/shadow.c +++ b/mm/kasan/shadow.c @@ -147,6 +147,40 @@ void kasan_poison(const void *addr, size_t size, u8 va= lue, bool init) } EXPORT_SYMBOL_GPL(kasan_poison); =20 +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 ((start_addr + size) % KASAN_GRANULE_SIZE) + return -EINVAL; + + end_addr =3D ALIGN_DOWN(start_addr + size, KASAN_GRANULE_SIZE); + if (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 ALIGN_DOWN(end_addr, KASAN_GRANULE_SIZE); + + 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); + #ifdef CONFIG_KASAN_GENERIC void kasan_poison_last_granule(const void *addr, size_t size) { --=20 2.51.0.384.g4c02a37b29-goog