From nobody Mon Jun 8 05:26:40 2026 Received: from mail-qk1-f202.google.com (mail-qk1-f202.google.com [209.85.222.202]) (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 CC16237D13D for ; Mon, 1 Jun 2026 20:00:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.222.202 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780344019; cv=none; b=bjsNYXWN7+7GGGrK6Uw8s9GpO+uDo5Ye+g8HUELFH4++5RR3QltSO96J+aBBPdUMA3fZNM+CNxBYTVVnm8312dkWJ6PHg7U1FIPYjWZEsLiKS7hBhtvJklFZbzQsi2pIvgKkgKyzKBrH+aGzR8xuo47OvZcpbYTaCeBMWpnoH7k= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780344019; c=relaxed/simple; bh=oyRMYCBipJFGfyqAL11a48wj6WtAhuqVNSVZiDf1eLI=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=jDO18KPZU7BzUPSlIz22Cu+vdl++9Oyd/B8M6OSVVcTG9OUF6DAebWkEvKXkIxPA8NHz7O2v8QbJTdSXAIRzGlwbvVTpVY5/KGnQXfdO2MgRaOoHwfxLuQhT5YQ/Mgltk6bBw3vvtVrIl/WEza/1c+6cP0Z+G87lVc62aEKH66Q= 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=CDHDznwi; arc=none smtp.client-ip=209.85.222.202 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="CDHDznwi" Received: by mail-qk1-f202.google.com with SMTP id af79cd13be357-9157a31ac37so8646485a.2 for ; Mon, 01 Jun 2026 13:00:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1780344016; x=1780948816; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=msbNDh9TiShw7R12hj6rcfm+XGYU44qZJxoBlWEONAk=; b=CDHDznwiq0j6K9sq4AIkVFeqNLP5QqSrI8nemAd0XRksZoinE7W/mpWiRtYVqLbj/k TuRjevMST1wvtW6iCud8yua2kqBWGXO2NhMoqLnsY6bkkixnwAqz4Betcy0MeFhMrB1W ECVpL31TqN6fQaeYsIpYlhADCi06obFO7PeKH2uy37KszFpb5+eZ826dmcClQoIVM7Ao 6lxm5yTxcupeFAQI3oL87LfCttljq0kIzJxMtc99uKuJEd55fSITjG/MOrNTYPBDXapM dvPDrPmhHa0OSaMd8ZTbNkYzZBiIYURNspyEAuUgYfW9/tLuXs49PGEmDfBRJ8lTc5Rl FaqQ== 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=LAZuMaz4hZaBsxPH36YqVin5mTSnpaZW8d+7NVhSPGv6wsAAdDum3Fd5e3ccKsIQRj 1iGSX4Dewpt31Hs+TeERmDrHDOeed2rdb8HZrewb42NCGoxpe6/ZAYu4jZSrH9MEAt5m g18GlCJYkZHknq5hsbqWQBI3weNC28NWnm+9PmsknabpunHApocjrSLyT1huL+Rf75cG OF2euQl44YnonoLxP55RhXfde3QUbVx33UPcQUxEzq9nxFG85J46IZqmz5sxv1RCnKE+ +J0h9GOhRSsKgT/JmiymKLuBTv9jBe6Veu1WfoLZmRHEr1ovZwcZ4lCvh7wuAK88GkPc VMSg== X-Forwarded-Encrypted: i=1; AFNElJ9jeX89fbUWg5U/56adPGTSMjO2zgUTyRpRedM6jIkHmukNN3414xcmHv7dHAJ+jB8XZ7zL9qJOG9HoI2g=@vger.kernel.org X-Gm-Message-State: AOJu0Yy6JjVFwf3Jv0MJ4EwhxOE+xSGKzP7KdvAfVUfoKgA+scb/6Tit tIj4MHqCsDxE7wsd3GLVLV9QS/YWIdyK8Zkb7tyd5JOunM/+5GwaI5ly77+Xp69cxNC6LQWEmpg NURk8fWIhhlJJ 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 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: <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-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 Reviewed-by: Kevin Tian --- 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 =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 | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/drivers/dma-buf/dma-buf-mapping.c b/drivers/dma-buf/dma-buf-ma= pping.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 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; @@ -133,6 +137,11 @@ struct sg_table *dma_buf_phys_vec_to_sgt(struct dma_bu= f_attachment *attach, } =20 nents =3D calc_sg_nents(dma->state, phys_vec, nr_ranges, size); + if (!nents) { + ret =3D -EINVAL; + goto err_free_state; + } + ret =3D sg_alloc_table(&dma->sgt, nents, GFP_KERNEL | __GFP_ZERO); if (ret) goto err_free_state; --=20 2.54.0.929.g9b7fa37559-goog