From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 14A5FC433E9 for ; Wed, 23 Dec 2020 03:09:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DBA47207B1 for ; Wed, 23 Dec 2020 03:08:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728306AbgLWCSt (ORCPT ); Tue, 22 Dec 2020 21:18:49 -0500 Received: from mail.kernel.org ([198.145.29.99]:46280 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728292AbgLWCSr (ORCPT ); Tue, 22 Dec 2020 21:18:47 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2B34A2339F; Wed, 23 Dec 2020 02:17:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1608689860; bh=iWzg31RLXFLyr1F1ofVX5D4HpfNs+Ez3nHD7pp/fla4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eeWid6RKZiaqsDY4+TXAMVkeEvAvIt9ZskHtJNnG5NPjDsjT853957VW3PA2G3YaH UQefbOP/bmDAHYrrdJaGtKX//Lv81rAcSKxIJJEnaseIAhQbtZwNNUGnA9a63UPlSk UrQpmy9DzRC+xIvEhgOdLr3ZlS/wUR1IeI7xeTc9rYjdPHHOaxiYEabKIiJmF99562 NU5LTaGuqeiZbZmEeGBW8hKmtPSdnFXxo7+o+zJQp7OSFJJB9BzgP2/2OsH1YubzNe epSf3MVXeyvOO0l4E0MQsopmMHBQ/d9WkuIFuh+Ma2LJ96vhuYJp2M2SDvY1H0Lm7N 70zbbANQRFxYw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Daniel Vetter , Gerald Schaefer , Daniel Vetter , Jason Gunthorpe , Dan Williams , Kees Cook , Andrew Morton , John Hubbard , =?UTF-8?q?J=C3=83=C2=A9r=C3=83=C2=B4me=20Glisse?= , Jan Kara , linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-media@vger.kernel.org, linux-s390@vger.kernel.org, Niklas Schnelle , Heiko Carstens , Sasha Levin Subject: [PATCH AUTOSEL 5.10 056/217] s390/pci: remove races against pte updates Date: Tue, 22 Dec 2020 21:13:45 -0500 Message-Id: <20201223021626.2790791-56-sashal@kernel.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20201223021626.2790791-1-sashal@kernel.org> References: <20201223021626.2790791-1-sashal@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Daniel Vetter [ Upstream commit a67a88b0b8de16b4cd6ad50bfe0e03605904dc75 ] 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 commit 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're 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: 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: Gerald Schaefer Cc: linux-s390@vger.kernel.org Cc: Niklas Schnelle Signed-off-by: Daniel Vetter Signed-off-by: Niklas Schnelle Signed-off-by: Heiko Carstens Signed-off-by: Sasha Levin --- 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 401cf670a2439..1a6adbc68ee8c 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; -- 2.27.0