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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 41649C678D4 for ; Mon, 16 Jan 2023 17:09:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234205AbjAPRJo (ORCPT ); Mon, 16 Jan 2023 12:09:44 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33818 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234215AbjAPRJS (ORCPT ); Mon, 16 Jan 2023 12:09:18 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0C5D3265A9 for ; Mon, 16 Jan 2023 08:49:53 -0800 (PST) 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 dfw.source.kernel.org (Postfix) with ESMTPS id 9DEEF6108C for ; Mon, 16 Jan 2023 16:49:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B6B4AC433D2; Mon, 16 Jan 2023 16:49:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1673887792; bh=WJUcanwjyblsc1ntcBylx4M4TKLiAvggkHBKzf8gpc0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vGTPwxnyTnKvOvu+s3DFb4ywpkMIfxrtiq+MpVfYyE1IFmczJxMkO/YnT3Z0Dz1A8 /8DJUSFvYtE1T1Q72iBLf6k3E854AakFvk+XP13EFEabLdRwoVAs6xfyB7KWCFuNn6 P3N9WEi6rdJuWG2h/axE0Ef7wSAW6rm3ZIIwqntw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Nicholas Piggin , Michael Ellerman , Sasha Levin Subject: [PATCH 4.19 283/521] powerpc/perf: callchain validate kernel stack pointer bounds Date: Mon, 16 Jan 2023 16:49:05 +0100 Message-Id: <20230116154859.807901927@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230116154847.246743274@linuxfoundation.org> References: <20230116154847.246743274@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Nicholas Piggin [ Upstream commit 32c5209214bd8d4f8c4e9d9b630ef4c671f58e79 ] The interrupt frame detection and loads from the hypothetical pt_regs are not bounds-checked. The next-frame validation only bounds-checks STACK_FRAME_OVERHEAD, which does not include the pt_regs. Add another test for this. The user could set r1 to be equal to the address matching the first interrupt frame - STACK_INT_FRAME_SIZE, which is in the previous page due to the kernel redzone, and induce the kernel to load the marker from there. Possibly this could cause a crash at least. If the user could induce the previous page to contain a valid marker, then it might be able to direct perf to read specific memory addresses in a way that could be transmitted back to the user in the perf data. Fixes: 20002ded4d93 ("perf_counter: powerpc: Add callchain support") Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20221127124942.1665522-4-npiggin@gmail.com Signed-off-by: Sasha Levin --- arch/powerpc/perf/callchain.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/powerpc/perf/callchain.c b/arch/powerpc/perf/callchain.c index 0af051a1974e..26a31a3b661e 100644 --- a/arch/powerpc/perf/callchain.c +++ b/arch/powerpc/perf/callchain.c @@ -68,6 +68,7 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *re next_sp = fp[0]; if (next_sp == sp + STACK_INT_FRAME_SIZE && + validate_sp(sp, current, STACK_INT_FRAME_SIZE) && fp[STACK_FRAME_MARKER] == STACK_FRAME_REGS_MARKER) { /* * This looks like an interrupt frame for an -- 2.35.1