From nobody Mon Jun 8 14:36:13 2026 Received: from mail-qt1-f201.google.com (mail-qt1-f201.google.com [209.85.160.201]) (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 55CFF34107D for ; Thu, 28 May 2026 19:17:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779995823; cv=none; b=L7SRuWe64f6FxIhE1nIw3EBFfHIao/dp5ZR+FdwZPox7ZnbMqJ20oZg7or1vldOoBEoNZciCurUEw9U7+MqF/llTvHF2YU69onxKwzw04tdc57uwu2kiNhym62rY1hsr1NN+U453ykHL9uunG5NI1tYwrIAdWvWL6wXjdF2Nwg8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779995823; c=relaxed/simple; bh=7nsiCepyNb7uhyn7v++Qgh6kBtGu5mTdr2I4JeUzJwg=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=JOBEOzeG2BchtIGIIHHtUY4KdLYPzqxj2rQiFWwOiusF8oy1wgXlFIEKpkVI/oG5X11w8zCxmhpL3OQhMRUl4u/hWGGexS7jijmfx/CqouUX+RN1OWHCzojpli9MLibsHEUSb4iPMIdVJ8FBLjfkG8e941P0Z4hXFXOl6GdSOXQ= 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=WBK5gB3g; arc=none smtp.client-ip=209.85.160.201 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="WBK5gB3g" Received: by mail-qt1-f201.google.com with SMTP id d75a77b69052e-5104b861649so60504041cf.1 for ; Thu, 28 May 2026 12:17:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1779995821; x=1780600621; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=ruTGaXcXn18lBWCvQSOsc+J+nN/WfLLq3tF9jPQMx3w=; b=WBK5gB3gz0knR7r1QSCw2Hgqe4P+flmyYn+HX4a6wgABeJudGCp9uiKxyM2G6QVCJH OWK91reZahY3emKrdytKrTEl2mImWVBoLoqfbE4FNkNZsCkofLk8F+FjUPga8PgsPSMq hcTtAlTCzVgPEBU8wynmFWad7DRL4ei5NYMpUk0uYMNN/2klnittp4erQaQ4iRJwyrSF Is5b+0ZfN1A7Yj8ETSjEMbGLN/9XW24dJOgbUOxk0t0jYJqjczWRS1p9XvGkHQQ6GoBE rIvujSOt8964PhapkcSA65LXa7HrGWmJ1j1z7/XMoqsspDEx+mUNjURsp0AzcPRyCNtO BCPg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1779995821; x=1780600621; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=ruTGaXcXn18lBWCvQSOsc+J+nN/WfLLq3tF9jPQMx3w=; b=I+zzUW//XDl6pbKyCYO2g0xpO230B7y8mbu1zHN2r13mn5SQZYuIXSQLJyXcjG0r9E KeUkCXcMU7j4OqgGkgXkdQouVQ55Tn3414ZOfsZrXWIjlzQJseS1gUZmsn3GHcEybv77 NSQ8yfWwKbYLXcOfLIiIjOWUv5qWrSMdUBJh5STRUFi1OcN3jUGdROfGEXVZSZfdXfmn Q2YULdYl1KDqAY7eVWL/XRQiPMkr5EH6W0u0NAn3YnRYcY3Dvh4eyauk2F2dZcRNY2ad zZljyj+8lf5CeexGh2GF1ONWPwtRzq1XjqsB90hmy5urfbfzJBhnAj+M391DNB0X/Zoq Ow5Q== X-Forwarded-Encrypted: i=1; AFNElJ/imcHC99VlBERZa3tcyvAKFrA/DDQF0itgIoz/Z3+JpAMMyfQRrURuJ5TgjErE5HZkarinHCa4t3JGjOg=@vger.kernel.org X-Gm-Message-State: AOJu0YzYgi4/9GwbSw5tFfVgfXbLO2no+XFoBaeB5a0dGkNfXbbxZM39 a9YgB0h6RhLJvjeVClneZJlU0lGP49sezrrHAHdvAqK+GvjdDOjMoHtM/zqKFblh3q1GQCB80ih oZvizRy4peH89 X-Received: from qtlo20.prod.google.com ([2002:ac8:4294:0:b0:50f:d8f5:705f]) (user=xuehaohu job=prod-delivery.src-stubby-dispatcher) by 2002:a05:622a:4c8c:b0:516:e8aa:271 with SMTP id d75a77b69052e-5172cb95a12mr2327291cf.26.1779995821046; Thu, 28 May 2026 12:17:01 -0700 (PDT) Date: Thu, 28 May 2026 19:16:58 +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 2.54.0.929.g9b7fa37559-goog Message-ID: <20260528191658.2506362-1-xuehaohu@google.com> Subject: [PATCH v4] dma-buf: Fix silent overflow for phys vec to sgt From: David Hu To: Sumit Semwal , "=?UTF-8?q?Christian=20K=C3=B6nig?=" Cc: Nicolin Chen , Leon Romanovsky , 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, 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. 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 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 =3D 0` initialization (previously stated as removed in the v2 changelog) as it is strictly required for the `+=3D` 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 | 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..1aabc0ee70bb 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 (WARN_ON_ONCE(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 2.54.0.929.g9b7fa37559-goog