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=1794063286; b=dHkMzkcKSz5HeNLsllYMN61STJeeCRR+VwtiBZfeY6Vuas6Aal59BX41t0SvCbTRJgOJ +r6wBRivL4ig3a9+bgIl3ZeI3E8SArXzsHvlAvuwUN5D7AkoZlw4LSbANBAbL/tmyVh8I Dg7bjUITNZdcMZxE5OqLCaw/eZNdhwn9Jp4ARfsmWQ7ZaEaPu8DRI1aNw1apyu1IAWAp7 iYMT+KWy0VR7koiWba5Fe6x3JFQatQQbkTYvceeeSa2p8u1RwR0jgQ+ZUpOHbb66QPY9J oIrKedPthGMDbc/8cgwouC16zCeqGdNlmO5i8n1y+kadoITJm6g9xS9GD6LQ863R91Q== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794063286; 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=XQ7MrLdMEqy7RY/ygZa0+Ik6tcv4XAneWat4tBcnK0Y=; b=n9OHcWM1nEmc8JzU3sJslkc/0ZLIeeh+wTZ0CT+XGZ/TgWbrZRkzmicdz3iQYAj2AZk9 ftXooTuZ3L1nW6iG/MbD8pZ0h1wIe25RmBEelsaUgV8jx/punM0XJ4B9QpEBogMDdTN49 35pCkhWgkqbnon6iDbuPL3xtllSuXJxJo/6AHGfS7JSISKQSRw8AKGXBURJqIwqDo4N7k Dpffiz7WJW8OUstg0S7D3OuywGdEpDoDoIn3O3PeOBT+HSXctLSnN9sxuOP09G6C5peWm QwE3qv9OsvcUUbsbm53BMivFcuAkMDhqV7Zk21d7LxH2mk++6VFXe+hBlAM+jO3cT6Q== 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=lKHZsx7h; 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 AFE19606D809; Sat, 7 Nov 2026 14:54:45 +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=lKHZsx7h Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6057F1F008A6; Sat, 7 Nov 2026 14:54:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794063285; bh=XQ7MrLdMEqy7RY/ygZa0+Ik6tcv4XAneWat4tBcnK0Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=lKHZsx7hrgOBV9QkDwBUcuw0u3T0fIUAv/8ybuly48QjWJ3uFiG2BOL7jgnR76FEC oXs1Ucbn0QRbWWyxwxsrct7RuIXRuywYnnaiMbhrwXxou8/xTlULP0I+Q6CjOVsXfK 85LhtcW/nrqguS53qfogz8Hsf8Dpc3VsD+/yVEpQ= 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 6.18 441/869] iommu/dma: Catch scatterlist length overflows Date: Sat, 7 Nov 2026 08:52:03 -0500 Message-ID: <20261107134908.719562028@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134852.069646174@linuxfoundation.org> References: <20261107134852.069646174@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 6.18-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 9da773ba550ba..aa9ebf2bc96ed 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -1453,6 +1453,11 @@ 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; /* @@ -1469,7 +1474,20 @@ 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