From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f42.google.com (mail-wm1-f42.google.com [209.85.128.42]) (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 080C53BB680 for ; Tue, 19 May 2026 20:35:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.42 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779222937; cv=none; b=JKDl/vcpFkEwP+EIPWQ5ml3F2F6VSZn/TLS07/2ZOzKQEW304/tvzrGGtrpZOKGsWyzoV6qa4NxxpVXYtsG5aeOKkNQSsHNwupa5cxa83wYgdd9jnWwpbayF+E4aUctnsQjGAp5EXAR6tFApdhc3Zvisk/81WlByM0YWCH4aeJk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779222937; c=relaxed/simple; bh=5nJqDD/dXtl9IILNdZwN304brhy7+urj60vJWRhs4Bw=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=GXNjbnUxe88PJFlXShqt5kObKizR3VnscO+kLPM6g9K4WmmQZvYS53nGOqNInF331INHODl1/P6CiAQo/XeY/RVbQQBnhLA0Eq18cbbbygn0Zc6iHk4h7IInkUeR7zwoGND6Ga+EHKDPsIYqFOaTtW1EiX1jR6YV7nJ6cTijYvs= 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=Syds0zMU; arc=none smtp.client-ip=209.85.128.42 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="Syds0zMU" Received: by mail-wm1-f42.google.com with SMTP id 5b1f17b1804b1-488af9fdaa7so19957745e9.1 for ; Tue, 19 May 2026 13:35:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1779222934; x=1779827734; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=e2iG1hz81YAuxXAiaPdaZ3OGfdkiju2FjT0lpwqJRqQ=; b=Syds0zMUNLUQH1tYRXypJNoepH1zZksTSknTM4XtDa9kmqg87iNHufLDAJIy/a9xxx lsegPg/0b2LYqktvO6Unryvegju0ik3q49nvfnTwsUTEZMfqnbm0t5Kn+c/gTmvOAjfL A9OZ8cx8ykCfAIWwtCTzxAI9WJPTmWBhpOLn/D7yOeYB3wOC0y9p6at61my2c4PPkhXr kklHwscHjEu5G+eOLdRYUO7oJcJuivtJnh3sP3Ve+SYbMVGQ9TQQzeKssET+t2186nKN OfnOpTWHI0iy2RWpevHB4Ir5ra+MObQobOhb8tbTkWLrtCKdK3qDNgwZ6+PNDaTAar1K V1Xw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1779222934; x=1779827734; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=e2iG1hz81YAuxXAiaPdaZ3OGfdkiju2FjT0lpwqJRqQ=; b=tJauBBfH0qv9KzSqliNE2UD4d4BrOS6fs54CQszvirhTCbVwXU6pf0iyoOOyZb+HIX 6wb5+W1/hzcTKPsccDmLS3b9lk3abAiHS369roomt2KhC5OT4nWZR6PL8pCNdsHDfIOI 4qHDsWEDxzT6uu767GM1QxYFA54fSgAxi8CRtzO4O/F61oBraZ9f0joI+vcyVt6EP87E ddcCcPbnvcOM5T/Gp5bOAudtenzAl5JLUkfpbjQIjFKkEUbVtPus3vhICfizAXkUYJ8A EBaPODbBfMl0hApRz2CgX8drgZ7pshs12QldMp1glE0cRUD05O9KozWdpmWNEUhXZHiT uQvQ== X-Gm-Message-State: AOJu0YyNYBxvyLtxOnI8e+R9w1jQ+rqPUaL32y8oQaCiFlbUivvjr8Az fLCcJqNUIYV+He6Pr6rrRk9bIcA+SmdaZfikkIN0/l6C0bLS37uAsX1XnnZB7vTyJVY= X-Gm-Gg: Acq92OH2+lK30mwNA2dUcgQ4BTEQvnljJ6VJhSouerNfKJoeYbHXFYGh+5J3VuQn/x3 f4afX0hM10x6mrirf0kxGYIaoCXUElf7fnVC90t7ccNkuDPSBg9eb11ggsPN68TtV1P8ZCyVHt7 cMomqVt6egbBXzXtGIbQR9pZQcUO4ev+APK4zwV4/1e5CFaYCGCPc2+D67slyLf+ok5O6JFGluj luutXwDzHzdsALe+dXORKxxZZOWv+4n3/rZUNvsjGx7yGRrNzD7WWs814e6Y0XilgZ5jbNo7gOB vBiqFYEgwc0FJEuq9ED9sH7f3JvCQdyq3OzAwOtWZ9w/5qzufxk3hw9gzeqYU3vUNTGJcxHz8PJ DsCC1MJYtWtJud+mg4Z2Kq9aYJfBBIapk5BVe1wlIDYLfFDRs8autI1fYruSDnm8wFFisT+Lum3 MahbtK0kuiJSeDbaKIvmPFIVpqdUTp07L9T4VyMWoU/UzKfJYewrgZ9feCapqN+mZdLWExDtTHI 8TC0xpCohU= X-Received: by 2002:a05:600c:5298:b0:48e:635a:18d2 with SMTP id 5b1f17b1804b1-48fe60e51d1mr328374555e9.2.1779222934041; Tue, 19 May 2026 13:35:34 -0700 (PDT) Received: from dohko.chello.ie (188-141-5-72.dynamic.upc.ie. [188.141.5.72]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4900c16c744sm177738225e9.3.2026.05.19.13.35.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 19 May 2026 13:35:33 -0700 (PDT) From: David Carlier To: netdev@vger.kernel.org Cc: stable@vger.kernel.org, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, sdf@fomichev.me, sdf.kernel@gmail.com, kaiyuanz@google.com, almasrymina@google.com, bobbyeshleman@gmail.com, linux-kernel@vger.kernel.org, David Carlier Subject: [PATCH net v2] net: devmem: reject dma-buf bind with non-page-aligned size or SG length Date: Tue, 19 May 2026 21:35:30 +0100 Message-ID: <20260519203530.66310-1-devnexen@gmail.com> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit net_devmem_bind_dmabuf() trusts dmabuf->size and sg_dma_len() to be PAGE_SIZE multiples without checking: - tx_vec is sized dmabuf->size / PAGE_SIZE, and net_devmem_get_niov_at() only bounds-checks virt_addr < dmabuf->size before indexing tx_vec[virt_addr / PAGE_SIZE]. With size = N*PAGE_SIZE + r (1 <= r < PAGE_SIZE), sendmsg() at iov_base = N*PAGE_SIZE passes the bound check and reads tx_vec[N] -- one past. - owner->area.num_niovs = len / PAGE_SIZE while gen_pool_add_owner() covers the full byte len, so a non-page-multiple non-final sg desyncs num_niovs from the gen_pool region for every later sg, on both RX and TX. dma-buf does not require page-aligned sizes, so the bind path has to enforce what its own indexing assumes. Reject both with -EINVAL. The size check is TX-only (only tx_vec is sized off dmabuf->size); the SG-length check covers both directions. Fixes: bd61848900bf ("net: devmem: Implement TX path") Cc: stable@vger.kernel.org Signed-off-by: David Carlier --- Changes in v2: - Reframe commit message around the kernel-side OOB instead of "real exporters already page-align", which read as the OOB being unreachable and undercut Cc: stable (Stanislav Fomichev). - Hoist the SG-length check out of the if (TX) branch so it covers RX too; RX has the same num_niovs / gen_pool desync on a contract-violating exporter, just without an OOB. Keep the size-multiple check TX-only (Stanislav Fomichev). - Drop bool todevice; compare direction == DMA_TO_DEVICE inline to match the existing call site at the tx_vec[] assignment (Bobby Eshleman). net/core/devmem.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/net/core/devmem.c b/net/core/devmem.c index 468344739db2..4f71de44c0fb 100644 --- a/net/core/devmem.c +++ b/net/core/devmem.c @@ -241,6 +241,11 @@ net_devmem_bind_dmabuf(struct net_device *dev, } if (direction == DMA_TO_DEVICE) { + if (!IS_ALIGNED(dmabuf->size, PAGE_SIZE)) { + err = -EINVAL; + NL_SET_ERR_MSG(extack, "TX dma-buf size must be a multiple of PAGE_SIZE"); + goto err_unmap; + } binding->tx_vec = kvmalloc_objs(struct net_iov *, dmabuf->size / PAGE_SIZE); if (!binding->tx_vec) { @@ -267,6 +272,12 @@ net_devmem_bind_dmabuf(struct net_device *dev, size_t len = sg_dma_len(sg); struct net_iov *niov; + if (!IS_ALIGNED(len, PAGE_SIZE)) { + err = -EINVAL; + NL_SET_ERR_MSG(extack, "dma-buf SG length must be PAGE_SIZE aligned"); + goto err_free_chunks; + } + owner = kzalloc_node(sizeof(*owner), GFP_KERNEL, dev_to_node(&dev->dev)); if (!owner) { -- 2.53.0