From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D5A5CCD6E55 for ; Mon, 1 Jun 2026 20:00:18 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 341E410E906; Mon, 1 Jun 2026 20:00:18 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=google.com header.i=@google.com header.b="JIKmLqKd"; dkim-atps=neutral Received: from mail-qk1-f202.google.com (mail-qk1-f202.google.com [209.85.222.202]) by gabe.freedesktop.org (Postfix) with ESMTPS id 1685810E906 for ; Mon, 1 Jun 2026 20:00:17 +0000 (UTC) Received: by mail-qk1-f202.google.com with SMTP id af79cd13be357-91550eceb13so354923085a.1 for ; Mon, 01 Jun 2026 13:00:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1780344016; x=1780948816; darn=lists.freedesktop.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=msbNDh9TiShw7R12hj6rcfm+XGYU44qZJxoBlWEONAk=; b=JIKmLqKdq7OVMw1Gnvl0VnnN7U2M5si4VQ2KsB2cfg2+6cgU5+TLbNkSY0mZwYfrqv iKdyzlzlyTUpfgudTb4AORglDnt6opvNWFn4xw0CROHySjOG2Ut6/FFtMT4xUczCw5IY 5Dq+gOAt5DczH5pkpo1NI9gHYGy1B8ZyY0prHYGZ3u5LbGzbujnlCCyUT9xn9vofUlTW Ce3ZIe5xkCStmH3odAgny6T/V4nKYb7JBCb+5Wo+GGln7aNgyU5wesKIDkEmHOPTaGok 5RWQsTtxBqra98FziOVMsPEuiR9orKQTwiVn0XX7+ZvuXZjLsNYOlnIQNcqg6hmELgDF bD0A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1780344016; x=1780948816; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=msbNDh9TiShw7R12hj6rcfm+XGYU44qZJxoBlWEONAk=; b=BcmpF9/OgKr0Y5vcsyg17u/VKwMOtCUGpl0Pg+m9jvRbVZ8vYBZ51NPwbE4eVDHcqI d7fjhv+82Qe6vuBnob43URPLpIc98mmxvl2pthMtNrSshKKQ/YHroFfzLixDMONYvU15 +kfh6gDIEOBEyr/owJ66rmKpSB6qZ2ynax05utpayKskg6lY6itlQTTVbuw9FYng5CVe NyeA9BT5NHKSrOSL8Yw6+TnzRStK0CmUylPyg0cXOqlWvReirt8n/YiBrqG4JRdioiLY 3UohxzCITZ78nUw86NiIMd/GRH6gGaHnM/Kg+uxYJy822lPK2Xh5EHKpa9h9y+DK9p3u PA+w== X-Forwarded-Encrypted: i=1; AFNElJ8XcrexZ3CZSU7IFEtgxPsliNVgpSCImPAgTDa0YBpUf1hb+B+sPvccw6i2FfBABg/Ofo2prkSOPTI=@lists.freedesktop.org X-Gm-Message-State: AOJu0Yzboly+hDMDFgVeCXt+40Xk5Rl3MiPon3Ba82Ffvt34rycIiX+M ocmHroACzBPath6J35QDl51ZBqXddFQvIfEjVALCrGLysiBvpmUVh7IgUZf0qVZmQRftI4CX8kg OhNnzRzG5Hw70 X-Received: from qknxz25.prod.google.com ([2002:a05:620a:5e19:b0:910:b90:6ec6]) (user=xuehaohu job=prod-delivery.src-stubby-dispatcher) by 2002:a05:620a:4612:b0:915:5930:94f1 with SMTP id af79cd13be357-91559309603mr1224141185a.47.1780344015096; Mon, 01 Jun 2026 13:00:15 -0700 (PDT) Date: Mon, 1 Jun 2026 20:00:12 +0000 Mime-Version: 1.0 X-Mailer: git-send-email 2.54.0.929.g9b7fa37559-goog Message-ID: <20260601200012.3872274-1-xuehaohu@google.com> Subject: [PATCH v5] dma-buf: Fix silent overflow for phys vec to sgt From: David Hu To: Sumit Semwal , "=?UTF-8?q?Christian=20K=C3=B6nig?=" Cc: Jason Gunthorpe , Nicolin Chen , Leon Romanovsky , Kevin Tian , Ankit Agrawal , Alex Williamson , linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org, iommu@lists.linux.dev, jmoroni@google.com, praan@google.com, David Hu , stable@vger.kernel.org Content-Type: text/plain; charset="UTF-8" X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" In case MMIO size is bigger than 4G and peer2peer DMA goes through host bridge, we trigger a code path that assigns the total linked IOVA (which is greater than 4G) to mapped_len. Previously, `mapped_len` was declared as 32-bit `unsigned int`. When accumulating `size_t` lengths, this leads to a silent wrap-around. This truncation causes truncated lengths to be passed to functions like `fill_sg_entry()`. Fix this by changing `mapped_len` to `size_t` (64-bit). While at it, fix similar potential overflow issues in `calc_sg_nents` by using `size_t` for `nents` and checking against `UINT_MAX` and using `unsigned int` for the loop iterator in `fill_sg_entry` to match. Fixes: 3aa31a8bb11e ("dma-buf: provide phys_vec to scatter-gather mapping routine") Cc: stable@vger.kernel.org Cc: iommu@lists.linux.dev Reviewed-by: Pranjal Shrivastava Signed-off-by: David Hu --- Changes in v5: - Removed WARN_ON_ONCE from calc_sg_nents() to avoid log noise (Jason). - Added explicit check for `!nents` in dma_buf_phys_vec_to_sgt() to cleanly return -EINVAL on overflow (Jason). Changes in v4: - Added WARN_ON_ONCE() to the nents overflow check to prevent silent failures (Claude Bot). Changes in v3: - Removed leftover sentence fragment from the commit message. - Kept `nents = 0` initialization (previously stated as removed in the v2 changelog) as it is strictly required for the `+=` accumulation loop in `calc_sg_nents()`. Changes in v2: - Fixed 'IVOA' -> 'IOVA' typo and expanded commit message (Claude Bot). - Added Reverse Xmas tree formatting (Pranjal). - Folded in extra bounds checking for calc_sg_nents() (Pranjal). - Folded in type consistency fix for fill_sg_entry() (Pranjal). drivers/dma-buf/dma-buf-mapping.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/drivers/dma-buf/dma-buf-mapping.c b/drivers/dma-buf/dma-buf-mapping.c index 794acff2546a..607b7998463d 100644 --- a/drivers/dma-buf/dma-buf-mapping.c +++ b/drivers/dma-buf/dma-buf-mapping.c @@ -10,7 +10,7 @@ static struct scatterlist *fill_sg_entry(struct scatterlist *sgl, size_t length, dma_addr_t addr) { unsigned int len, nents; - int i; + unsigned int i; nents = DIV_ROUND_UP(length, UINT_MAX); for (i = 0; i < nents; i++) { @@ -36,7 +36,7 @@ static unsigned int calc_sg_nents(struct dma_iova_state *state, struct phys_vec *phys_vec, size_t nr_ranges, size_t size) { - unsigned int nents = 0; + size_t nents = 0; size_t i; if (!state || !dma_use_iova(state)) { @@ -51,6 +51,9 @@ static unsigned int calc_sg_nents(struct dma_iova_state *state, nents = DIV_ROUND_UP(size, UINT_MAX); } + if (nents > UINT_MAX) + return 0; + return nents; } @@ -95,9 +98,10 @@ struct sg_table *dma_buf_phys_vec_to_sgt(struct dma_buf_attachment *attach, size_t nr_ranges, size_t size, enum dma_data_direction dir) { - unsigned int nents, mapped_len = 0; struct dma_buf_dma *dma; struct scatterlist *sgl; + size_t mapped_len = 0; + unsigned int nents; dma_addr_t addr; size_t i; int ret; @@ -133,6 +137,11 @@ struct sg_table *dma_buf_phys_vec_to_sgt(struct dma_buf_attachment *attach, } nents = calc_sg_nents(dma->state, phys_vec, nr_ranges, size); + if (!nents) { + ret = -EINVAL; + goto err_free_state; + } + ret = sg_alloc_table(&dma->sgt, nents, GFP_KERNEL | __GFP_ZERO); if (ret) goto err_free_state; -- 2.54.0.929.g9b7fa37559-goog