From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 597263009E4 for ; Mon, 3 Nov 2025 11:02:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762167729; cv=none; b=nPKBIAxYYF+UcA9F1dK6rSVbje6wO6gnajxkgpNhUB1Ju+LbalPdXPULjrgxWCimhLrGN5r0kBVfgpt5aBeYpfmgNGEhQRGwlUTqTjmSJ4wIHhNSCryFuDI3N4SPvZzG1WPtBJYVkbM1oeX8S/gwRLWiASBGM3GQ1gh1uiQ/WLc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762167729; c=relaxed/simple; bh=dBEGE7Q2FKfgjAlIXnLQQ3kv27gx1kpdPQtSwVZaBLg=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=fEH5wfRYxRob1DG02B8oRYYkMYOfh1WCAEvUMxgQIXAslA/9XClumz1hsRDanwQS1fGTw8GDOv8bnokMyAMRTQFZwo+fkADm4dvTIJ5OmVMf3uR9Ydagb+I7dYS5llZVURlrv9vdiDGRfrkjOv2onCZjFW8Cr0h+M4r9FOQVDMY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Zq8xyZaP; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Zq8xyZaP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 742AAC4CEE7; Mon, 3 Nov 2025 11:02:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1762167727; bh=dBEGE7Q2FKfgjAlIXnLQQ3kv27gx1kpdPQtSwVZaBLg=; h=From:To:Cc:Subject:Date:From; b=Zq8xyZaPRCiSAPW57VhpsgAiTBwBqP6XkDgxOvn5vZzA1sYnqgh0RK5mD5wnjGYGK Hu0MC0hbd6ILJ24QPsYjK8AvwJlo6q3ygStghGvD32c6OmXG8C5HjncIMB9PZpxato J4d2LnumJHSpZbzkzdQ0c+4R7sixgMQU/dRonIMHaL5Em2sFwnlppVzwgrIZhsXuG3 Og0dec424Y3aGwlYl0f+1ns2Q6LnPqADoaWiu6OjG0zo0fVswYDtBIWirBCBfuYtW2 Ex22L8WzhNXm3fHjLOWEViWi8YdGBaF1JvcxixiNfx8swlRvyHsquMloLFfUCHjitS seAV/qWGeefQg== From: Pratyush Yadav To: Andrew Morton , Baoquan He , Alexander Graf , Mike Rapoport , Pasha Tatashin , Pratyush Yadav Cc: kexec@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH] kho: fix out-of-bounds access of vmalloc chunk Date: Mon, 3 Nov 2025 12:01:57 +0100 Message-ID: <20251103110159.8399-1-pratyush@kernel.org> X-Mailer: git-send-email 2.51.2 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The list of pages in a vmalloc chunk is NULL-terminated. So when looping through the pages in a vmalloc chunk, both kho_restore_vmalloc() and kho_vmalloc_unpreserve_chunk() rightly make sure to stop when encountering a NULL page. But when the chunk is full, the loops do not stop and go past the bounds of chunk->phys, resulting in out-of-bounds memory access, and possibly the restoration or unpreservation of an invalid page. Fix this by making sure the processing of chunk stops at the end of the array. Fixes: a667300bd53f2 ("kho: add support for preserving vmalloc allocations") Signed-off-by: Pratyush Yadav --- Notes: Commit 89a3ecca49ee8 ("kho: make sure page being restored is actually from KHO") was quite helpful in catching this since kho_restore_page() errored out due to missing magic number, instead of "restoring" a random page and causing errors at other random places. kernel/kexec_handover.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/kexec_handover.c b/kernel/kexec_handover.c index 76f0940fb4856..cc5aaa738bc50 100644 --- a/kernel/kexec_handover.c +++ b/kernel/kexec_handover.c @@ -869,7 +869,7 @@ static void kho_vmalloc_unpreserve_chunk(struct kho_vmalloc_chunk *chunk) __kho_unpreserve(track, pfn, pfn + 1); - for (int i = 0; chunk->phys[i]; i++) { + for (int i = 0; i < ARRAY_SIZE(chunk->phys) && chunk->phys[i]; i++) { pfn = PHYS_PFN(chunk->phys[i]); __kho_unpreserve(track, pfn, pfn + 1); } @@ -992,7 +992,7 @@ void *kho_restore_vmalloc(const struct kho_vmalloc *preservation) while (chunk) { struct page *page; - for (int i = 0; chunk->phys[i]; i++) { + for (int i = 0; i < ARRAY_SIZE(chunk->phys) && chunk->phys[i]; i++) { phys_addr_t phys = chunk->phys[i]; if (idx + contig_pages > total_pages) base-commit: dcb6fa37fd7bc9c3d2b066329b0d27dedf8becaa -- 2.47.3