From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794064578; b=jj8Za/0NPcWHv3n+yKFJnJpGD/XcQ1Lv0+DKHxwR3wboq+dHzspp/+QHRfA0ZtQ/8AkK IvtVm+UQ+wULLXmhghHDeay3MSKX9UPhGdM49+mSdTXCMSw6RyiEOym86HHMaZr7c7r9C dBDkeWJbBRNHdvZwVYVKUqS1GXQalhVLcMwquuL5CK4TKALIsJT3qPg1Bj97+cxTmfe1w VLA15AubSrISgswDeIEDVRPiBCnJ9VdWOdjpQTqLKOZ+WGqWsesIX3oYadDGl5hVay9cB J2cMGlTwGG7Ve0Jl9dnAmgD9GtzDAcQJXI27/1At1/VhjXpzt+v86xinkifMs218hPg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794064578; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=wbLugK9uVtd/K0G8ZxuHGP3wGPzA7IRj2I5Vop+4vuQ=; b=SzxlZUQIW74J9styno7SodaFudcwQczPVnBf4xFuZOHSK2sJEPdlCAHlz5d5bKQ4ps+z yqcauBoJYcDrGNigorN0TbrIN0yv6P8O3oLV/Dsq6Vb5onW0Z+8lvV2+/YqDuM/b1ETTe eeHzegDL7Y86BtdPMCq4w/D3V1Ja93eXYkxR3MEw3oweUAbymvQWZF6wckD2+izn+oW49 fidV9gDkedJbdDiXU1iPm9qyAOnR2aZ9xt+0tLg3Aw6YFtbH0GYI2sy3doIuJfN3bmdms vkmyDMV8ibmJa5tNMLp7NWlcyq6GBPHwGva6AqZaG5JSfIKkoL0JgiNoFmZWH2xc+MA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=hZJdMcTf; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C000C606D809; Sat, 7 Nov 2026 15:16:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=hZJdMcTf Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6D95F1F0089F; Sat, 7 Nov 2026 15:16:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794064577; bh=wbLugK9uVtd/K0G8ZxuHGP3wGPzA7IRj2I5Vop+4vuQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=hZJdMcTfvnibQQ0LbSUx0PddzDDwEI831VjnqNi0wkMpaLVvq0K5I7fqE3dk+PtgU DubKwivnEK293X0ML14mRduqIVY2T4RqW/pZ+ELd8i7Cnn/lPsL3bP5gzbp42Ji91u OFnDgJJchuPZ/HVY8168kSGJ18MAOL4vcEIahipY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Krzysztof Karas , Robin Murphy , Sebastian Brzezinka , Joerg Roedel , Sasha Levin Subject: [PATCH 7.3 0597/1257] iommu/dma: Catch scatterlist length overflows Date: Sat, 7 Nov 2026 08:48:13 -0500 Message-ID: <20261107134955.813952460@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134939.434104957@linuxfoundation.org> References: <20261107134939.434104957@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.3-stable review patch. If anyone has any objections, please let me know. ------------------ From: Krzysztof Karas [ Upstream commit 1c8f6308e557f32412e9d4678b3f029f47f6d9aa ] It is possible, when a very large mapping uses only one scatterlist, that padding overflows scatterlist's length field. This results in: 1) silently wrapping the value 2) smaller than desired mappings produced by iommu_map_sg 3) leaving mapped bytes in memory (no iommu_unmap) Address this issue by adding overflow detection for scatterlist length field. Fixes: 809eac54cdd6 ("iommu/dma: Implement scatterlist segment merging") Cc: stable@vger.kernel.org Assisted-by: LLM Signed-off-by: Krzysztof Karas Reviewed-by: Robin Murphy Reviewed-by: Sebastian Brzezinka Signed-off-by: Joerg Roedel Signed-off-by: Sasha Levin --- drivers/iommu/dma-iommu.c | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index 68ee57800fefc..795a0d6248ceb 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -1477,6 +1477,11 @@ int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg, int nents, sg_dma_len(s) = s_length; s->offset -= s_iova_off; s_length = iova_align(iovad, s_length + s_iova_off); + if (overflows_type(s_length, s->length)) { + ret = -EOVERFLOW; + + goto out_restore_sg; + } s->length = s_length; /* @@ -1493,7 +1498,20 @@ int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg, int nents, * time through here (i.e. before it has a meaningful value). */ if (pad_len && pad_len < s_length - 1) { - prev->length += pad_len; + unsigned int new_prev_len; + + /* + * For large mappings spanning multiple GBs we + * may not be able to fit all needed padding into + * sg->length. + */ + if (check_add_overflow(prev->length, pad_len, &new_prev_len)) { + ret = -EOVERFLOW; + + goto out_restore_sg; + } + + prev->length = new_prev_len; iova_len += pad_len; } -- 2.53.0