From nobody Mon Jun 8 17:55:57 2026 Received: from mail-qv1-f73.google.com (mail-qv1-f73.google.com [209.85.219.73]) (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 A84BC36493E for ; Wed, 27 May 2026 20:50:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.73 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779915053; cv=none; b=dcUGUc06zIRq1J0ogJdDxjWSMSXupO4kpsIRSnHw6x0FAd2eaQTgBvA/d4LGUjnjjVev/PqK8c/P6oqoBQidZy7bR1xBVya4D2H0N3teijceYj66SOVC3JNoLeOKyhJ4ZoXeZUGV6ohIiuGkTHOyQxoziXE62GDSJhmU7Kxtbdw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779915053; c=relaxed/simple; bh=eRR5kbIsSk8uR68Yt/RxW5wJjv4k6qQ3jUkESRdonS4=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=NQYlrmLHN50XfvBAcToWq4hnMoWiDEd8KYhXKBh+7m6JnZKQe9L+SVhGpbxpXdmi98FRHaRSk0h7x4scSCi1K7vUilCCYyb4dMdGbYePa1lMbr/qNdXbGjH6XW7agNusIGh0EPom5WrdsycvzicY+Dv4PTraRGHowLIJF9N36j4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--xuehaohu.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=iNqSXfM3; arc=none smtp.client-ip=209.85.219.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--xuehaohu.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="iNqSXfM3" Received: by mail-qv1-f73.google.com with SMTP id 6a1803df08f44-8acadca1ac4so85614976d6.0 for ; Wed, 27 May 2026 13:50:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1779915051; x=1780519851; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=OnsOZAwcaFX6qrXTkZ3llO87kDjoRN0331vlXYrms0w=; b=iNqSXfM37Tmxky1BVl8faF9mFcxHtxZXQT3kYGd1cCpSVzT2qkeqIMHmr5py3Izxhq WL0s0xUJcTywlm7QR46hLKSRfZ4NTKxv7WA1HTMYa0Me67JPJ9v+TI7vJJ/LjOm3Z1CF fK9V6AAMq1eZ1/Q3F48MajYW7RiEg8ZcFDRmbyO4klZqmV34pVngvDkX+QqL2uWMfA9J DMY0ysA406GJtmp2Q7GmMrAp4cLckKXltx/hA1keAtIsqavJ4r3IbW3CErnh5fVVfwZF wDyiQICo+zGFu3rDumZpk8axgHOlK8wgPw5i28I3ujfQZb3kt+adq0WNkOmVW3UlGbpa Kzog== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1779915051; x=1780519851; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=OnsOZAwcaFX6qrXTkZ3llO87kDjoRN0331vlXYrms0w=; b=nJ9bIQBeGPa3kPEBoRB7x5FoABvQSmVckExH7axN+/YM3aW2q8TZW2syaIllk6elMn Tl7lpYLXbNAysPNFftL/v9eqH9gP4tC9JB7ZxP9/aYZdjjpjnyZlKO2RwHx6Rlq8Jgjb mXorkPlpo3r11mTyQl5dFTfKLaitpjrWf/tX+WR7F49/XZEsfSOEfhSX81mKWklsblmt buM9QyCHZTNRxai2iEErzYUb6At0z1DHN9HEnAkcnCUkjhcB0DrSaLTvkheJfedVcQek xQI5dfEQmejCbTilGlR0sQkxweczn5xJNQx/RZL95UVxyF30PFbenPVJTH5H2Jumxkk6 bPkw== X-Forwarded-Encrypted: i=1; AFNElJ8cbdeXAWb0jiR8+yzUylbdh/ZvuFBfRqo50SFqEKoO/ipKJToRq/KNoL/Bm2Q1DBk5EWPlFoA8pg4WFV4=@vger.kernel.org X-Gm-Message-State: AOJu0Yw+JvKVD7g1Bet9qsHcA1M/mABkSW0xOUoUZ9pJMBm4WpGq/Ui4 f9NgiSM/fCZ/2i2JYI7o5VHOPEh6rAKgA74ueBiGp+I6HPfVUa9B0GmO5xnf1ku4US/FGP83gQk AEZ5ta4Xv5QyU X-Received: from qviu6.prod.google.com ([2002:a0c:c486:0:b0:8cc:2486:6603]) (user=xuehaohu job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6214:54ca:b0:8ac:b237:9fb5 with SMTP id 6a1803df08f44-8cc7b5fe0d8mr387104406d6.49.1779915050519; Wed, 27 May 2026 13:50:50 -0700 (PDT) Date: Wed, 27 May 2026 20:50:47 +0000 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.54.0.794.g4f17f83d09-goog Message-ID: <20260527205048.2168808-1-xuehaohu@google.com> Subject: [PATCH v2] dma-buf: Fix silent overflow for phys vec to sgt From: David Hu To: Sumit Semwal , "=?UTF-8?q?Christian=20K=C3=B6nig?=" Cc: Kevin Tian , Ankit Agrawal , Jason Gunthorpe , Alex Williamson , linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org, jmoroni@google.com, praan@google.com, leonro@nvidia.com, David Hu , stable@vger.kernel.org, iommu@lists.linux.dev Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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. to mapped_len, and leading to a silent overflow Fixes: 3aa31a8bb11e ("dma-buf: provide phys_vec to scatter-gather mapping r= outine") Cc: stable@vger.kernel.org Cc: iommu@lists.linux.dev Reviewed-by: Pranjal Shrivastava Signed-off-by: David Hu --- 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). Droped unnecessary `nents =3D 0` initialization (Claude Bot). drivers/dma-buf/dma-buf-mapping.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/dma-buf/dma-buf-mapping.c b/drivers/dma-buf/dma-buf-ma= pping.c index 794acff2546a..5bc769fc42ea 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 scatterli= st *sgl, size_t length, dma_addr_t addr) { unsigned int len, nents; - int i; + unsigned int i; =20 nents =3D DIV_ROUND_UP(length, UINT_MAX); for (i =3D 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 =3D 0; + size_t nents =3D 0; size_t i; =20 if (!state || !dma_use_iova(state)) { @@ -51,6 +51,9 @@ static unsigned int calc_sg_nents(struct dma_iova_state *= state, nents =3D DIV_ROUND_UP(size, UINT_MAX); } =20 + if (nents > UINT_MAX) + return 0; + return nents; } =20 @@ -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 =3D 0; struct dma_buf_dma *dma; struct scatterlist *sgl; + size_t mapped_len =3D 0; + unsigned int nents; dma_addr_t addr; size_t i; int ret; --=20 2.54.0.794.g4f17f83d09-goog