From nobody Fri Dec 19 07:23:40 2025 Received: from mail-pf1-f201.google.com (mail-pf1-f201.google.com [209.85.210.201]) (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 CF7FB1BBBCC for ; Fri, 30 Aug 2024 19:26:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725046003; cv=none; b=UUepBlCoIXXVJ26Su7p7+vFokT2ihZo/D9soebleWQkrRxcKlXekd8789K+85cYE4vyjUeh67fuKLX58tTjwjM5+S/dEMmCVgk4JX22YpuEeDkFUEyu7IL2GQ5CJj6ViCe1YmumbHVm967jXz8wsW8zuIZ/pO4tg6/TqOQfCfLo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725046003; c=relaxed/simple; bh=8QVHSbxNTzTLHDg1HVfV1vyaxEg8m3Y3kEmk4ONuLIw=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=SqzBQ+vSKQxric+wyARlNE1N7aZ7vSuaH5uuCHEYv7NDdFe1P2s/T+8r8tRaRqOAZDqt2vV4C7wUd88oo96oeBaVi8huU/+p0dm7PhE3wRTahVyBCrzxZSXEy2V+ChIAsMnEp/63RXLkWzFz3zErnytuYQrnZ05b+3XIk0+yHvE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--tjmercier.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=ZradwWnG; arc=none smtp.client-ip=209.85.210.201 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--tjmercier.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ZradwWnG" Received: by mail-pf1-f201.google.com with SMTP id d2e1a72fcca58-7141ab07fddso1937913b3a.0 for ; Fri, 30 Aug 2024 12:26:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1725046000; x=1725650800; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=FuDRdZr3lnXIzC7C2IwkgUCCNdeMT8LTC1OgvHLHr0o=; b=ZradwWnG8IGjO1RyDHLcT1zpjxOiiS8oTt5cQ2TqaPIlVryG5CVghopJTjq5sAAQCp EDlLJxcZrD3MQnj8P7rLI5jDr74RgzzYSqoF8USz4zV9xz7Efdkna5V6lqpRz8skk+z2 oR0DgvIIXL5FDc4c5N3HJvDgii64X3kIV7ItTWi9M98NOxSVxnOMmYpicIgvCkfvllMK fpD/KbvqLRE2FGefXlqlEPpMytlLb7zzPBbmDBFVQVpzaca09BkMu3LcWoMjyNO8MPyK wsrWPDNZvd9BlIXGYSUFZWTDGqU4kzhFlnRd+eF6TrtT5ul5hyIXu02fQVsOudKUTrfE f0Mw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1725046000; x=1725650800; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=FuDRdZr3lnXIzC7C2IwkgUCCNdeMT8LTC1OgvHLHr0o=; b=Gnc+mXnbkQ0nz2iKogD89jMNgKhzzC5tT9JagRuegY3Un8z2gTQROeE2y1r4w6cKNN 9/Fbc33dRFh7oWP88Ml1yYMsjQhYmiO1Oue+sqqOrq/bvk45ki6uGWcT6Jk6DL8w8Brr 0qeqwOFmZeHt9PdLe+4EfByQPrn2pWSQsCfmGHErOkuE90kvT0JlOSoWOGNzQF4TjVMX tv39CiRufAc/Zw82g8FQDHrlfnzLpbQUFZVentOfKtrr7V3MT8TmKJnOeqZokqxSRwiu gBOL+sMkRuHO6+Bj3COYPdLaII6fpOWGLpMwIxIZKg/+jj0k+gvzi1mPJFme4pgAyFwP Rypw== X-Forwarded-Encrypted: i=1; AJvYcCU92k32gxKSfo3hZf0gJIYxYF5WcNFPKuSXLVXbLRQgkdEDiYHkJzqBnroyI0vnWGURBte6hINn5MJHFOc=@vger.kernel.org X-Gm-Message-State: AOJu0YzsCEEveaA/pRXcYXiTg9vOy3A7cp1cHzIMe0s/959mMPcRDMa2 JgTHAG6I29eG72iCA4V971VuGF5C3geQJpQtCqfGogg1OLKOxbP66vt+Zn5YyrFHtAUf7gTcUDZ EseUO+VCgzbdFUA== X-Google-Smtp-Source: AGHT+IEYDT5yTYPujoEQ0Ej+aCUk5iv9pvxNQHghRZEWhY4u/r1jH/tjVnZ/WpOzBL4HVQ0C2o97rg0PjRinvWA= X-Received: from tj-virt.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5683]) (user=tjmercier job=sendgmr) by 2002:a05:6a00:8585:b0:714:1436:1cef with SMTP id d2e1a72fcca58-717307cbc9bmr7143b3a.6.1725045999943; Fri, 30 Aug 2024 12:26:39 -0700 (PDT) Date: Fri, 30 Aug 2024 19:26:26 +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 2.46.0.469.g59c65b2a67-goog Message-ID: <20240830192627.2546033-1-tjmercier@google.com> Subject: [PATCH] dma-buf: heaps: Fix off-by-one in CMA heap fault handler From: "T.J. Mercier" To: Sumit Semwal , Benjamin Gaignard , Brian Starkey , John Stultz , "T.J. Mercier" , "=?UTF-8?q?Christian=20K=C3=B6nig?=" Cc: android-mm@google.com, Xingyu Jin , stable@vger.kernel.org, John Stultz , Brian Starkey , linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Until VM_DONTEXPAND was added in commit 1c1914d6e8c6 ("dma-buf: heaps: Don't track CMA dma-buf pages under RssFile") it was possible to obtain a mapping larger than the buffer size via mremap and bypass the overflow check in dma_buf_mmap_internal. When using such a mapping to attempt to fault past the end of the buffer, the CMA heap fault handler also checks the fault offset against the buffer size, but gets the boundary wrong by 1. Fix the boundary check so that we don't read off the end of the pages array and insert an arbitrary page in the mapping. Reported-by: Xingyu Jin Fixes: a5d2d29e24be ("dma-buf: heaps: Move heap-helper logic into the cma_h= eap implementation") Cc: stable@vger.kernel.org # Applicable >=3D 5.10. Needs adjustments only f= or 5.10. Signed-off-by: T.J. Mercier Acked-by: John Stultz --- drivers/dma-buf/heaps/cma_heap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/dma-buf/heaps/cma_heap.c b/drivers/dma-buf/heaps/cma_h= eap.c index c384004b918e..93be88b805fe 100644 --- a/drivers/dma-buf/heaps/cma_heap.c +++ b/drivers/dma-buf/heaps/cma_heap.c @@ -165,7 +165,7 @@ static vm_fault_t cma_heap_vm_fault(struct vm_fault *vm= f) struct vm_area_struct *vma =3D vmf->vma; struct cma_heap_buffer *buffer =3D vma->vm_private_data; =20 - if (vmf->pgoff > buffer->pagecount) + if (vmf->pgoff >=3D buffer->pagecount) return VM_FAULT_SIGBUS; =20 return vmf_insert_pfn(vma, vmf->address, page_to_pfn(buffer->pages[vmf->p= goff])); --=20 2.46.0.469.g59c65b2a67-goog