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 5D845C433F5 for ; Mon, 20 Dec 2021 15:02:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240906AbhLTPCT (ORCPT ); Mon, 20 Dec 2021 10:02:19 -0500 Received: from ams.source.kernel.org ([145.40.68.75]:34030 "EHLO ams.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237542AbhLTO4Y (ORCPT ); Mon, 20 Dec 2021 09:56:24 -0500 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 D1502B80EF2; Mon, 20 Dec 2021 14:56:22 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0E154C36AF8; Mon, 20 Dec 2021 14:56:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1640012181; bh=KbG2sf3M/w5o6lkbivBdu3cIy6jqTVRS6yXejm+KbIw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Bh74io0nFtOhNIz1nh4on71SK2n1bf6LWyyDU2FUmfmFYk1rBWOqGwUtQYJlZWTmq mWbkrIaE+73lijRBFGmBbXUXiPRqa7q7EFJlJVNMzELaiAUt1BxRFOL14mcx0ChLnb zOxr+3a3nluBIEHgWK53Vv1/NkQXpQcVXX6G7LJs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexei Starovoitov , Daniel Borkmann , Sasha Levin Subject: [PATCH 5.15 110/177] bpf: Fix extable fixup offset. Date: Mon, 20 Dec 2021 15:34:20 +0100 Message-Id: <20211220143043.773689575@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20211220143040.058287525@linuxfoundation.org> References: <20211220143040.058287525@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Alexei Starovoitov [ Upstream commit 433956e91200734d09958673a56df02d00a917c2 ] The prog - start_of_ldx is the offset before the faulting ldx to the location after it, so this will be used to adjust pt_regs->ip for jumping over it and continuing, and with old temp it would have been fixed up to the wrong offset, causing crash. Fixes: 4c5de127598e ("bpf: Emit explicit NULL pointer checks for PROBE_LDX instructions.") Signed-off-by: Alexei Starovoitov Reviewed-by: Daniel Borkmann Signed-off-by: Daniel Borkmann Signed-off-by: Sasha Levin --- arch/x86/net/bpf_jit_comp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 9ea57389c554b..462d8e68b3f43 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -1332,7 +1332,7 @@ st: if (is_imm8(insn->off)) * End result: x86 insn "mov rbx, qword ptr [rax+0x14]" * of 4 bytes will be ignored and rbx will be zero inited. */ - ex->fixup = (prog - temp) | (reg2pt_regs[dst_reg] << 8); + ex->fixup = (prog - start_of_ldx) | (reg2pt_regs[dst_reg] << 8); } break; -- 2.33.0