From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ej1-f42.google.com (mail-ej1-f42.google.com [209.85.218.42]) (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 21592346E59 for ; Wed, 15 Jul 2026 14:23:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.218.42 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784125434; cv=none; b=IPyoJK8fyMuvim+ngHm3UbH8J3ihWQNAOkdVCbR5ORsreinwvm/kdUHVBI3eZakSSPvhbeO0iZ8holGqzRmSBD/uYip9GVtNVs8q/+Zfj9CpncGyNHT7/AHMsB1jLV88461OXb3A5sc+ALbmNW/15hx/nktQALcWacnxP0vhzYI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784125434; c=relaxed/simple; bh=iLWHG7Z9ifkUCPM3I0W59CT2LgsbHMZPMVoaijdCcg4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FnvkMHGlqFcMkMz7LA/5bjm/6jiwKTtaGbv9lOhPdnigATUvpNYA0k+dZKsNV6IV7E36um4QDGrElgXAgRtHNbyD+7GRIp5aAe7aKiERgX9enIQ8JXH9x5Nn2mY3X+mTChbIyemmfQRvTF3RI7JxKz+LOzTfSv7i6yG6g5cuOn0= 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=G8Cz0cxB; arc=none smtp.client-ip=209.85.218.42 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="G8Cz0cxB" Received: by mail-ej1-f42.google.com with SMTP id a640c23a62f3a-c15ea93028dso602258066b.3 for ; Wed, 15 Jul 2026 07:23:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1784125429; x=1784730229; 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:content-type; bh=Yo/c4CjAVn9rvKKIkMq0mVxy9jNtcNfgzZTIdJ3Ac40=; b=G8Cz0cxBtjZI0A9OyzvOVe6WaDTjkAUQo2PQl5As98uHjZvBKeIntteGshxapy31iy 5ZzjLZJTHP7I6PfqnmNCtT4CHiRiue/ICKfXltfGJirarB+D3diuhWLL9U3IgI0V7a0Q S39zWowuqHX9asgmkJR3zT1mIkGMrRqGCr8zfqnVFfHl4UL9R31hue5mewjcVqdXOP5p ylwwMF2Ojl9MZ8sO2ju1ItEc+qLoOtClTUYBnOrj5jZcVoA/qc3VY4yJetlC78n6GvCS qIPaVsJ7ycejdCn3BUgIdByHVOfdTbY10v0W642S/+s5OyGQh6ZxXC1ebZWLRqQC71QR +N9A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1784125429; x=1784730229; 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:content-type; bh=Yo/c4CjAVn9rvKKIkMq0mVxy9jNtcNfgzZTIdJ3Ac40=; b=ncbGM9bTy5iT2WeywQ0fycPv5ELND4A/p3eS7fqOsXvfaEIFSvut7/D9s8b25vNw6t tax9QvxaBwgvyV21nUSpMVcLWN1E+dz4sgLGrK118+JS/Nv6zxWERJpkl696t6uvF4+B yjEPFKZOkWCE4Zd3nmcHX0DJ63F4DRWQcaIbQONrVG60/6DlKlT1W69FRaPem9sGt79H 5tjogDgm6WtqxEYOu80WxlnbYNdQf2lyd5H4nOiYEj/SdhJ5AZo98bGuYU2S4+ALBsb8 JFg7mQ3RNKLitpEpZ0SyB9XMuqMHzTau2tbsaGfYwbcU6IUx0grVVmmp+tIW5gzXgWfz RUmw== X-Forwarded-Encrypted: i=1; AHgh+RrcE+ZTrcPpTUBHBh5ErHRYNsQ+apQQFDg6FL/Ybr76+mpnTRkV9irlQRT1n20zSXMb+A/L5YhRrSq+iJE=@vger.kernel.org X-Gm-Message-State: AOJu0YxVFkeY6BUNim85GG92PCMn3WtdgSfLHLf1Vol8cceR0txY7r/V 5SpakhU6ZPNxTjj5zEHc1cHhz3GCPpALPAuU37JJTyEmhHHSGjqatIBn X-Gm-Gg: AfdE7cmlRSVhp2jnCy6yta8KWaArE7gQjnufugeZ37gbkd90j4vPDGaszqjiJzVlnzQ 7LlbbpvXjLJ4XiIp9vlPuhzzDVKfEfEwbDvmFssROm3/GA4wXaDow0bDoHDbNlwf2/+lTxZifhs SGiJ8eKvONyHADVIcT84oJbrlQuBN29+tRn3li3jQpE+kUJ3zad7+S/9f/WZ348SDlGr95DRShz +bQkmyywpeZpceFDmCV/w8BNwCf25iSMve3nRbeYMolBfL5HPjtSvFTKxewxVlCKZM+ZTFFhnvA 3NYHrdgtBlFC0+FW/g+AKWJGVOYorgo3SzLwnet5n6U9Tcl38X8XYTLx9QaTh1SRuoeuxuaN8sw j4A4NhFIkob16wdspfO9fIPyv9AEmAMbveEkh46MrKtFc48cCLdo/8aoO8wDRdU4ElQFdjPaVx+ K+My2g+ed5nz1fBEtX8Xg0k2KIKsHYUbVTdAVZTj46/BtaZF3Mfkx6fz+cwJAvv5Ogr4pl72YIB 8JI1yHMkq/Y7lk= X-Received: by 2002:a17:907:e1ca:20b0:c16:8933:3501 with SMTP id a640c23a62f3a-c1689334452mr16024566b.42.1784125428901; Wed, 15 Jul 2026 07:23:48 -0700 (PDT) Received: from misharu.home (2a02-a463-a071-0-8f3f-3afb-28f6-19c0.fixed6.kpn.net. [2a02:a463:a071:0:8f3f:3afb:28f6:19c0]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-c168744bd40sm38743766b.43.2026.07.15.07.23.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Jul 2026 07:23:48 -0700 (PDT) From: Hari Mishal To: Amit Shah , Arnd Bergmann , Greg Kroah-Hartman , Gerd Hoffmann , "Michael S . Tsirkin" , Jason Wang , David Hildenbrand , Henrik Rydberg Cc: Xuan Zhuo , =?UTF-8?q?Eugenio=20P=C3=A9rez?= , virtualization@lists.linux.dev, linux-kernel@vger.kernel.org, linux-input@vger.kernel.org, Hari Mishal Subject: [PATCH 1/4] virtio-mem: validate device-reported block size Date: Wed, 15 Jul 2026 16:22:40 +0200 Message-ID: <20260715142337.22811-2-harimishal1@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260715142337.22811-1-harimishal1@gmail.com> References: <20260715142337.22811-1-harimishal1@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: 8bit The device_block_size read from the virtio-mem config space is used as a divisor and also in ALIGN_DOWN() further down the code path in the driver without further validation. A zero value leads to a division by zero, and a non-power-of-two value corrupts the ALIGN_DOWN() bitmask arithmetic leading to a misreporting of guest usable guest ram, post crash. Reject both at init time instead of trusting the device. Assisted-by: gkh_clanker:t1000 Signed-off-by: Hari Mishal --- drivers/virtio/virtio_mem.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c index 11c441501582..43d12ec7c323 100644 --- a/drivers/virtio/virtio_mem.c +++ b/drivers/virtio/virtio_mem.c @@ -2847,6 +2847,13 @@ static int virtio_mem_init(struct virtio_mem *vm) &vm->plugged_size); virtio_cread_le(vm->vdev, struct virtio_mem_config, block_size, &vm->device_block_size); + if (!vm->device_block_size || + !is_power_of_2(vm->device_block_size)) { + dev_err(&vm->vdev->dev, + "invalid device block size: 0x%llx\n", + (unsigned long long)vm->device_block_size); + return -EINVAL; + } virtio_cread_le(vm->vdev, struct virtio_mem_config, node_id, &node_id); vm->nid = virtio_mem_translate_node_id(vm, node_id); -- 2.43.0