From patchwork Wed Apr 29 21:49:50 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jann Horn X-Patchwork-Id: 11518587 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 9281515E6 for ; Wed, 29 Apr 2020 21:50:37 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 6D620214AF for ; Wed, 29 Apr 2020 21:50:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="kzZp9oJp"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=google.com header.i=@google.com header.b="hq7/1zfU" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6D620214AF Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:To:From:Subject:References:Mime-Version :Message-Id:In-Reply-To:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=swVXf+92JXyJ4vJLxRWSb5s71RW1mCHIsBYRTGg1jEU=; b=kzZp9oJpWUK+AB HnbGBEffFGWvEgZHWZhaDWU3FVnefM6OpBT1Iuw30Nm/OvuiucT42w3lSB+WG8pkardYT/hG/ZLXS CLttBCWtEu5fwwDFD8rHLV0VpbdP+lKqOvJU2esCCsHC830wHwkR7C9UJ3px6LRjSpuZ5JR1HL32V LZAKCx3Z/13qVGmbhcgElMHeoTSoBPGmd8/wjlb6X4sDVyBchbk3uOk1R26dVS8YF6Z+ks9HRlBZK 8NXz5F11cGJIdPzNieaeOxCLQ076viOqj2nJ5fmie7BsJ22D3P4tW6zZc0yonU8GQrO3RWx73pFk4 ZShibTqzdQ0f1YuXYFrw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jTubA-0000GW-Pg; Wed, 29 Apr 2020 21:50:32 +0000 Received: from mail-yb1-xb4a.google.com ([2607:f8b0:4864:20::b4a]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jTuas-0008Rw-OC for linux-arm-kernel@lists.infradead.org; Wed, 29 Apr 2020 21:50:17 +0000 Received: by mail-yb1-xb4a.google.com with SMTP id e2so5132251ybm.19 for ; Wed, 29 Apr 2020 14:50:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=X8Ilta2TozKsEzasXrZac28hkMQagz57pEK9xvAhCMU=; b=hq7/1zfUEsP2iAtt4ZQ4PwzfpMH/LEAjv1O6M4T2kyI5ocMSPyrezh78agwH8E2fzC 5UoVyHnot4yvU3uT3T/gW30svDPED38wwzcwKUzc1ikntjBs+9t1DIScbtC1T7t5gt+O mS6z/RcBXMryw96KRHKWMXSzRFEqU6HnTb477iWgeCgmihZ523VW2z3+tpWL0Olncc0H DbIb3P9b+pQ9ux7Mr0Ope9w48HA1d2qcLTAWT5s9KeaNQb1A3h6o/n0bM6oiKdKbONLG xXvcA9wtEp7X3YvX7oN/lCMYNvQZ5hT+jnRwGzIUoXJDAz6icA6ycOc2YEueJSe+gqSn I33Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=X8Ilta2TozKsEzasXrZac28hkMQagz57pEK9xvAhCMU=; b=e4ff/vSmw2rfaKHHbxHzAWZKDGYPNLUtLvR2rmrOrLLPK56aW5yZ9iicd4Zog4xTpj KiOLh/ezoqb7Ti9rcu1bZ1yuMX4qenSX3et6uU1JoO+5lL5my5UeDAZm4lORwUhbvhss bpawDXwNPJugz2jnZJjuDKadB/s8TQtEsB9uxnhzpYA9HwRbMfdbr43qiDddNlZ9Wsd9 A1g8KfKI8wp76QHNV1bTqjzdoWt+CkjvKIJX2jvKWARIqP139dLIPaKJFHcYy6ddIQsd hCQnSB45B2WucPUVMfz3MVfpMpdM5EggzX7hqtxZZCudNwBrqctXNE+AqeghPJPfhAbu A35g== X-Gm-Message-State: AGi0PuaXrkZ7vglQj9zd/xa2ERh9W+hy+ce5W+0RofHv+0qw1L58B3go N5GbAC+Qm+wjJU8ZZo63xWdmRrdcRg== X-Google-Smtp-Source: APiQypK393UboBZKtVhF2VXC53kboONpVDbYMmk4wx3dfVKrxYMarbZX5Q8DMVWqcVWoG5mrxwWJr8Q+6w== X-Received: by 2002:a25:c048:: with SMTP id c69mr565867ybf.169.1588197012786; Wed, 29 Apr 2020 14:50:12 -0700 (PDT) Date: Wed, 29 Apr 2020 23:49:50 +0200 In-Reply-To: <20200429214954.44866-1-jannh@google.com> Message-Id: <20200429214954.44866-2-jannh@google.com> Mime-Version: 1.0 References: <20200429214954.44866-1-jannh@google.com> X-Mailer: git-send-email 2.26.2.526.g744177e7f7-goog Subject: [PATCH v2 1/5] binfmt_elf_fdpic: Stop using dump_emit() on user pointers on !MMU From: Jann Horn To: Andrew Morton X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200429_145014_790324_63E61065 X-CRM114-Status: GOOD ( 14.79 ) X-Spam-Score: -7.7 (-------) X-Spam-Report: SpamAssassin version 3.4.4 on bombadil.infradead.org summary: Content analysis details: (-7.7 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at https://www.dnswl.org/, no trust [2607:f8b0:4864:20:0:0:0:b4a listed in] [list.dnswl.org] -7.5 USER_IN_DEF_DKIM_WL From: address is in the default DKIM white-list -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature -0.0 DKIMWL_WL_MED DKIMwl.org - Medium sender X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Rich Felker , linux-c6x-dev@linux-c6x.org, Yoshinori Sato , linux-sh@vger.kernel.org, linux-kernel@vger.kernel.org, Oleg Nesterov , linux-mm@kvack.org, Alexander Viro , Mark Salter , linux-fsdevel@vger.kernel.org, Russell King , Aurelien Jacquiot , Linus Torvalds , Christoph Hellwig , linux-arm-kernel@lists.infradead.org, "Eric W . Biederman" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org dump_emit() is for kernel pointers, and VMAs describe userspace memory. Let's be tidy here and avoid accessing userspace pointers under KERNEL_DS, even if it probably doesn't matter much on !MMU systems - especially given that it looks like we can just use the same get_dump_page() as on MMU if we move it out of the CONFIG_MMU block. Signed-off-by: Jann Horn --- fs/binfmt_elf_fdpic.c | 8 ------ mm/gup.c | 58 +++++++++++++++++++++---------------------- 2 files changed, 29 insertions(+), 37 deletions(-) diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c index c62c17a5c34a9..f5b47076fa762 100644 --- a/fs/binfmt_elf_fdpic.c +++ b/fs/binfmt_elf_fdpic.c @@ -1495,14 +1495,11 @@ static bool elf_fdpic_dump_segments(struct coredump_params *cprm) struct vm_area_struct *vma; for (vma = current->mm->mmap; vma; vma = vma->vm_next) { -#ifdef CONFIG_MMU unsigned long addr; -#endif if (!maydump(vma, cprm->mm_flags)) continue; -#ifdef CONFIG_MMU for (addr = vma->vm_start; addr < vma->vm_end; addr += PAGE_SIZE) { bool res; @@ -1518,11 +1515,6 @@ static bool elf_fdpic_dump_segments(struct coredump_params *cprm) if (!res) return false; } -#else - if (!dump_emit(cprm, (void *) vma->vm_start, - vma->vm_end - vma->vm_start)) - return false; -#endif } return true; } diff --git a/mm/gup.c b/mm/gup.c index 50681f0286ded..76080c4dbff05 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -1490,35 +1490,6 @@ int __mm_populate(unsigned long start, unsigned long len, int ignore_errors) up_read(&mm->mmap_sem); return ret; /* 0 or negative error code */ } - -/** - * get_dump_page() - pin user page in memory while writing it to core dump - * @addr: user address - * - * Returns struct page pointer of user page pinned for dump, - * to be freed afterwards by put_page(). - * - * Returns NULL on any kind of failure - a hole must then be inserted into - * the corefile, to preserve alignment with its headers; and also returns - * NULL wherever the ZERO_PAGE, or an anonymous pte_none, has been found - - * allowing a hole to be left in the corefile to save diskspace. - * - * Called without mmap_sem, but after all other threads have been killed. - */ -#ifdef CONFIG_ELF_CORE -struct page *get_dump_page(unsigned long addr) -{ - struct vm_area_struct *vma; - struct page *page; - - if (__get_user_pages(current, current->mm, addr, 1, - FOLL_FORCE | FOLL_DUMP | FOLL_GET, &page, &vma, - NULL) < 1) - return NULL; - flush_cache_page(vma, addr, page_to_pfn(page)); - return page; -} -#endif /* CONFIG_ELF_CORE */ #else /* CONFIG_MMU */ static long __get_user_pages_locked(struct task_struct *tsk, struct mm_struct *mm, unsigned long start, @@ -1565,6 +1536,35 @@ static long __get_user_pages_locked(struct task_struct *tsk, } #endif /* !CONFIG_MMU */ +/** + * get_dump_page() - pin user page in memory while writing it to core dump + * @addr: user address + * + * Returns struct page pointer of user page pinned for dump, + * to be freed afterwards by put_page(). + * + * Returns NULL on any kind of failure - a hole must then be inserted into + * the corefile, to preserve alignment with its headers; and also returns + * NULL wherever the ZERO_PAGE, or an anonymous pte_none, has been found - + * allowing a hole to be left in the corefile to save diskspace. + * + * Called without mmap_sem, but after all other threads have been killed. + */ +#ifdef CONFIG_ELF_CORE +struct page *get_dump_page(unsigned long addr) +{ + struct vm_area_struct *vma; + struct page *page; + + if (__get_user_pages(current, current->mm, addr, 1, + FOLL_FORCE | FOLL_DUMP | FOLL_GET, &page, &vma, + NULL) < 1) + return NULL; + flush_cache_page(vma, addr, page_to_pfn(page)); + return page; +} +#endif /* CONFIG_ELF_CORE */ + #if defined(CONFIG_FS_DAX) || defined (CONFIG_CMA) static bool check_dax_vmas(struct vm_area_struct **vmas, long nr_pages) {