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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 42A00C4332F for ; Thu, 22 Dec 2022 18:14:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=7wwDixQ35SLex1UgaF/nxE3PlAcP2Oib0V3qwz+CkjU=; b=gWqCWdbTHwXFzs P0d3Rog0NjUcQUdD/Q3XA1wKCftHK+QskMfmugBzhivle39sx/Kw//aj719rRtGlLv5QXKpLiyRvv c/vq7uNTxgsgdfMt+N8vDJYObDv1G9aEbxQvwgTl7a1NJTv75zS1AikZ6WV0N20V5gfonzaTBX4+m L0NovVPeKt24JxEW8uh2u0m55gfBbWGtl6YoJ97sjKqLZaP2AzgX78XGhnYZXXBJR2cwA1JiVN+/Q 6vpBrfMikyL8vYsKjchJ5xPYGUXynqYtX2MLM+erCGoIfiprFPYYFpjKEyZiOZMyW/90gISuNKAbe HNdoRdyeZ7CL/8JDeelQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1p8Q4c-00FRGl-UJ; Thu, 22 Dec 2022 18:13:43 +0000 Received: from ams.source.kernel.org ([2604:1380:4601:e00::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1p8Q40-00FR7X-7w for linux-arm-kernel@lists.infradead.org; Thu, 22 Dec 2022 18:13:06 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id A7738B81F31; Thu, 22 Dec 2022 18:13:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DE896C433F1; Thu, 22 Dec 2022 18:12:59 +0000 (UTC) From: Catalin Marinas To: Will Deacon , Seth Jenkins Cc: Eric Biederman , Kees Cook , Greg Kroah-Hartman , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org Subject: [PATCH 3/3] arm64: mte: Avoid the racy walk of the vma list during core dump Date: Thu, 22 Dec 2022 18:12:51 +0000 Message-Id: <20221222181251.1345752-4-catalin.marinas@arm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20221222181251.1345752-1-catalin.marinas@arm.com> References: <20221222181251.1345752-1-catalin.marinas@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221222_101304_589563_E2B8C565 X-CRM114-Status: GOOD ( 18.20 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org The MTE coredump code in arch/arm64/kernel/elfcore.c iterates over the vma list without the mmap_lock held. This can race with another process or userfaultfd concurrently modifying the vma list. Change the for_each_mte_vma macro and its callers to instead use the vma snapshot taken by dump_vma_snapshot() and stored in the cprm object. Fixes: 6dd8b1a0b6cb ("arm64: mte: Dump the MTE tags in the core file") Cc: # 5.18.x Signed-off-by: Catalin Marinas Reported-by: Seth Jenkins Suggested-by: Seth Jenkins Cc: Will Deacon --- arch/arm64/kernel/elfcore.c | 56 +++++++++++++++++-------------------- 1 file changed, 26 insertions(+), 30 deletions(-) diff --git a/arch/arm64/kernel/elfcore.c b/arch/arm64/kernel/elfcore.c index b2388f15223e..662a61e5e75e 100644 --- a/arch/arm64/kernel/elfcore.c +++ b/arch/arm64/kernel/elfcore.c @@ -8,28 +8,27 @@ #include #include -#define for_each_mte_vma(vmi, vma) \ +#define for_each_mte_vma(cprm, i, m) \ if (system_supports_mte()) \ - for_each_vma(vmi, vma) \ - if (vma->vm_flags & VM_MTE) + for (i = 0, m = cprm->vma_meta; \ + i < cprm->vma_count; \ + i++, m = cprm->vma_meta + i) \ + if (m->flags & VM_MTE) -static unsigned long mte_vma_tag_dump_size(struct vm_area_struct *vma) +static unsigned long mte_vma_tag_dump_size(struct core_vma_metadata *m) { - if (vma->vm_flags & VM_DONTDUMP) - return 0; - - return vma_pages(vma) * MTE_PAGE_TAG_STORAGE; + return (m->dump_size >> PAGE_SHIFT) * MTE_PAGE_TAG_STORAGE; } /* Derived from dump_user_range(); start/end must be page-aligned */ static int mte_dump_tag_range(struct coredump_params *cprm, - unsigned long start, unsigned long end) + unsigned long start, unsigned long len) { int ret = 1; unsigned long addr; void *tags = NULL; - for (addr = start; addr < end; addr += PAGE_SIZE) { + for (addr = start; addr < start + len; addr += PAGE_SIZE) { struct page *page = get_dump_page(addr); /* @@ -78,11 +77,11 @@ static int mte_dump_tag_range(struct coredump_params *cprm, Elf_Half elf_core_extra_phdrs(struct coredump_params *cprm) { - struct vm_area_struct *vma; + int i; + struct core_vma_metadata *m; int vma_count = 0; - VMA_ITERATOR(vmi, current->mm, 0); - for_each_mte_vma(vmi, vma) + for_each_mte_vma(cprm, i, m) vma_count++; return vma_count; @@ -90,18 +89,18 @@ Elf_Half elf_core_extra_phdrs(struct coredump_params *cprm) int elf_core_write_extra_phdrs(struct coredump_params *cprm, loff_t offset) { - struct vm_area_struct *vma; - VMA_ITERATOR(vmi, current->mm, 0); + int i; + struct core_vma_metadata *m; - for_each_mte_vma(vmi, vma) { + for_each_mte_vma(cprm, i, m) { struct elf_phdr phdr; phdr.p_type = PT_AARCH64_MEMTAG_MTE; phdr.p_offset = offset; - phdr.p_vaddr = vma->vm_start; + phdr.p_vaddr = m->start; phdr.p_paddr = 0; - phdr.p_filesz = mte_vma_tag_dump_size(vma); - phdr.p_memsz = vma->vm_end - vma->vm_start; + phdr.p_filesz = mte_vma_tag_dump_size(m); + phdr.p_memsz = m->end - m->start; offset += phdr.p_filesz; phdr.p_flags = 0; phdr.p_align = 0; @@ -115,26 +114,23 @@ int elf_core_write_extra_phdrs(struct coredump_params *cprm, loff_t offset) size_t elf_core_extra_data_size(struct coredump_params *cprm) { - struct vm_area_struct *vma; + int i; + struct core_vma_metadata *m; size_t data_size = 0; - VMA_ITERATOR(vmi, current->mm, 0); - for_each_mte_vma(vmi, vma) - data_size += mte_vma_tag_dump_size(vma); + for_each_mte_vma(cprm, i, m) + data_size += mte_vma_tag_dump_size(m); return data_size; } int elf_core_write_extra_data(struct coredump_params *cprm) { - struct vm_area_struct *vma; - VMA_ITERATOR(vmi, current->mm, 0); - - for_each_mte_vma(vmi, vma) { - if (vma->vm_flags & VM_DONTDUMP) - continue; + int i; + struct core_vma_metadata *m; - if (!mte_dump_tag_range(cprm, vma->vm_start, vma->vm_end)) + for_each_mte_vma(cprm, i, m) { + if (!mte_dump_tag_range(cprm, m->start, m->dump_size)) return 0; } _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel