From patchwork Fri Oct 9 07:59:25 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Daniel Vetter X-Patchwork-Id: 11825203 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6BA0F109B for ; Fri, 9 Oct 2020 08:00:21 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 064F4222C2 for ; Fri, 9 Oct 2020 08:00:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=ffwll.ch header.i=@ffwll.ch header.b="bCCEbrj8" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 064F4222C2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ffwll.ch Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 8BCF86EC86; Fri, 9 Oct 2020 08:00:13 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mail-wr1-x443.google.com (mail-wr1-x443.google.com [IPv6:2a00:1450:4864:20::443]) by gabe.freedesktop.org (Postfix) with ESMTPS id 9D4D66ECAB for ; Fri, 9 Oct 2020 08:00:05 +0000 (UTC) Received: by mail-wr1-x443.google.com with SMTP id m6so9257641wrn.0 for ; Fri, 09 Oct 2020 01:00:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=X4YPw4aMBEIEW3EKL3Rrjh8cYpxDDu/3udcPtwUh360=; b=bCCEbrj8HXwsYeCGdtRhueW/WP3h5AIUVs+0WKR5JezCZAxpSZJLP7pJbouSWNLwcP Siv24sIgXKCEbpQ5T7HWnt5hai8j4gqTeIle2FvkXGfHuEX2Ja+XvENt3NXUpNLV6z9i mhbDix/VH2lJsWJIvcVQl1Cf7Nhf3QI7cNCDw= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=X4YPw4aMBEIEW3EKL3Rrjh8cYpxDDu/3udcPtwUh360=; b=hWLVvLdIX5nLPAfZftjJevFfrhqTWCyDx2s00pU6eYItWmPST+ExmqvSNZZgLxKTil Cd/2gNr7PggVo+Kv6cGj+KlD9Y0YwkdJLNZhCDr/kZjZLpQBiF4HoG0uYhU0OUmXpIRt lq79saqH1OEAt/681EAhVHTGsUb0QYiOqGxESrS/4N+sZ18z46yA7ce8D1llqo2GiHK/ hxmHZaDxj3gJgu/KjG25Tshk2juks0gGDtCavzP6FVvKPS1knmCCzp+T522RNdXi+mNV gjLm1WFTBwTNsiB6Jn+CRYAJsZ8TuDlC3MFc/2PJKaWjRy2fN3WDAhD4OdFzd42IEAfM smeQ== X-Gm-Message-State: AOAM5300VZeRcmaVmb52/2fCAsbaTXGSHK68q7qIHsJCaWFxS5ALNG1O WNG8KiG8wPcgwb9ctMvNHPuwQ8UwoUeJVwU/ X-Google-Smtp-Source: ABdhPJwzQNY2KcIc5e/GuTH1z0+BpDCjhxbMoVaEX6dxiObPD8e9HbCzPtgw4CPmEpaFAJRAX6EU4g== X-Received: by 2002:a5d:5449:: with SMTP id w9mr14288781wrv.182.1602230403743; Fri, 09 Oct 2020 01:00:03 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id u17sm11634118wri.45.2020.10.09.01.00.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 09 Oct 2020 01:00:03 -0700 (PDT) From: Daniel Vetter To: DRI Development , LKML Subject: [PATCH v2 08/17] s390/pci: Remove races against pte updates Date: Fri, 9 Oct 2020 09:59:25 +0200 Message-Id: <20201009075934.3509076-9-daniel.vetter@ffwll.ch> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201009075934.3509076-1-daniel.vetter@ffwll.ch> References: <20201009075934.3509076-1-daniel.vetter@ffwll.ch> MIME-Version: 1.0 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: , Cc: linux-s390@vger.kernel.org, linux-samsung-soc@vger.kernel.org, Jan Kara , Kees Cook , kvm@vger.kernel.org, Jason Gunthorpe , Daniel Vetter , Niklas Schnelle , Andrew Morton , linux-mm@kvack.org, =?utf-8?b?SsOpcsO0bWUgR2xpc3Nl?= , John Hubbard , Daniel Vetter , Gerald Schaefer , Dan Williams , linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Way back it was a reasonable assumptions that iomem mappings never change the pfn range they point at. But this has changed: - gpu drivers dynamically manage their memory nowadays, invalidating ptes with unmap_mapping_range when buffers get moved - contiguous dma allocations have moved from dedicated carvetouts to cma regions. This means if we miss the unmap the pfn might contain pagecache or anon memory (well anything allocated with GFP_MOVEABLE) - even /dev/mem now invalidates mappings when the kernel requests that iomem region when CONFIG_IO_STRICT_DEVMEM is set, see 3234ac664a87 ("/dev/mem: Revoke mappings when a driver claims the region") Accessing pfns obtained from ptes without holding all the locks is therefore no longer a good idea. Fix this. Since zpci_memcpy_from|toio seems to not do anything nefarious with locks we just need to open code get_pfn and follow_pfn and make sure we drop the locks only after we've done. The write function also needs the copy_from_user move, since we can't take userspace faults while holding the mmap sem. Reviewed-by: Gerald Schaefer Signed-off-by: Daniel Vetter Cc: Jason Gunthorpe Cc: Dan Williams Cc: Kees Cook Cc: Andrew Morton Cc: John Hubbard Cc: Jérôme Glisse Cc: Jan Kara Cc: Dan Williams Cc: linux-mm@kvack.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-samsung-soc@vger.kernel.org Cc: linux-media@vger.kernel.org Cc: Niklas Schnelle Cc: Gerald Schaefer Cc: linux-s390@vger.kernel.org Acked-by: Niklas Schnelle --- v2: Move VM_IO | VM_PFNMAP checks around so they keep returning EINVAL like before (Gerard) --- arch/s390/pci/pci_mmio.c | 98 +++++++++++++++++++++++----------------- 1 file changed, 57 insertions(+), 41 deletions(-) diff --git a/arch/s390/pci/pci_mmio.c b/arch/s390/pci/pci_mmio.c index 401cf670a243..1a6adbc68ee8 100644 --- a/arch/s390/pci/pci_mmio.c +++ b/arch/s390/pci/pci_mmio.c @@ -119,33 +119,15 @@ static inline int __memcpy_toio_inuser(void __iomem *dst, return rc; } -static long get_pfn(unsigned long user_addr, unsigned long access, - unsigned long *pfn) -{ - struct vm_area_struct *vma; - long ret; - - mmap_read_lock(current->mm); - ret = -EINVAL; - vma = find_vma(current->mm, user_addr); - if (!vma) - goto out; - ret = -EACCES; - if (!(vma->vm_flags & access)) - goto out; - ret = follow_pfn(vma, user_addr, pfn); -out: - mmap_read_unlock(current->mm); - return ret; -} - SYSCALL_DEFINE3(s390_pci_mmio_write, unsigned long, mmio_addr, const void __user *, user_buffer, size_t, length) { u8 local_buf[64]; void __iomem *io_addr; void *buf; - unsigned long pfn; + struct vm_area_struct *vma; + pte_t *ptep; + spinlock_t *ptl; long ret; if (!zpci_is_enabled()) @@ -158,7 +140,7 @@ SYSCALL_DEFINE3(s390_pci_mmio_write, unsigned long, mmio_addr, * We only support write access to MIO capable devices if we are on * a MIO enabled system. Otherwise we would have to check for every * address if it is a special ZPCI_ADDR and would have to do - * a get_pfn() which we don't need for MIO capable devices. Currently + * a pfn lookup which we don't need for MIO capable devices. Currently * ISM devices are the only devices without MIO support and there is no * known need for accessing these from userspace. */ @@ -176,21 +158,37 @@ SYSCALL_DEFINE3(s390_pci_mmio_write, unsigned long, mmio_addr, } else buf = local_buf; - ret = get_pfn(mmio_addr, VM_WRITE, &pfn); + ret = -EFAULT; + if (copy_from_user(buf, user_buffer, length)) + goto out_free; + + mmap_read_lock(current->mm); + ret = -EINVAL; + vma = find_vma(current->mm, mmio_addr); + if (!vma) + goto out_unlock_mmap; + if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) + goto out_unlock_mmap; + ret = -EACCES; + if (!(vma->vm_flags & VM_WRITE)) + goto out_unlock_mmap; + + ret = follow_pte_pmd(vma->vm_mm, mmio_addr, NULL, &ptep, NULL, &ptl); if (ret) - goto out; - io_addr = (void __iomem *)((pfn << PAGE_SHIFT) | + goto out_unlock_mmap; + + io_addr = (void __iomem *)((pte_pfn(*ptep) << PAGE_SHIFT) | (mmio_addr & ~PAGE_MASK)); - ret = -EFAULT; if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE) - goto out; - - if (copy_from_user(buf, user_buffer, length)) - goto out; + goto out_unlock_pt; ret = zpci_memcpy_toio(io_addr, buf, length); -out: +out_unlock_pt: + pte_unmap_unlock(ptep, ptl); +out_unlock_mmap: + mmap_read_unlock(current->mm); +out_free: if (buf != local_buf) kfree(buf); return ret; @@ -274,7 +272,9 @@ SYSCALL_DEFINE3(s390_pci_mmio_read, unsigned long, mmio_addr, u8 local_buf[64]; void __iomem *io_addr; void *buf; - unsigned long pfn; + struct vm_area_struct *vma; + pte_t *ptep; + spinlock_t *ptl; long ret; if (!zpci_is_enabled()) @@ -287,7 +287,7 @@ SYSCALL_DEFINE3(s390_pci_mmio_read, unsigned long, mmio_addr, * We only support read access to MIO capable devices if we are on * a MIO enabled system. Otherwise we would have to check for every * address if it is a special ZPCI_ADDR and would have to do - * a get_pfn() which we don't need for MIO capable devices. Currently + * a pfn lookup which we don't need for MIO capable devices. Currently * ISM devices are the only devices without MIO support and there is no * known need for accessing these from userspace. */ @@ -306,22 +306,38 @@ SYSCALL_DEFINE3(s390_pci_mmio_read, unsigned long, mmio_addr, buf = local_buf; } - ret = get_pfn(mmio_addr, VM_READ, &pfn); + mmap_read_lock(current->mm); + ret = -EINVAL; + vma = find_vma(current->mm, mmio_addr); + if (!vma) + goto out_unlock_mmap; + if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) + goto out_unlock_mmap; + ret = -EACCES; + if (!(vma->vm_flags & VM_WRITE)) + goto out_unlock_mmap; + + ret = follow_pte_pmd(vma->vm_mm, mmio_addr, NULL, &ptep, NULL, &ptl); if (ret) - goto out; - io_addr = (void __iomem *)((pfn << PAGE_SHIFT) | (mmio_addr & ~PAGE_MASK)); + goto out_unlock_mmap; + + io_addr = (void __iomem *)((pte_pfn(*ptep) << PAGE_SHIFT) | + (mmio_addr & ~PAGE_MASK)); if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE) { ret = -EFAULT; - goto out; + goto out_unlock_pt; } ret = zpci_memcpy_fromio(buf, io_addr, length); - if (ret) - goto out; - if (copy_to_user(user_buffer, buf, length)) + +out_unlock_pt: + pte_unmap_unlock(ptep, ptl); +out_unlock_mmap: + mmap_read_unlock(current->mm); + + if (!ret && copy_to_user(user_buffer, buf, length)) ret = -EFAULT; -out: if (buf != local_buf) kfree(buf); return ret;