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 4FCAEC3ABB6 for ; Tue, 6 May 2025 02:29:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=tgnN4Domvqg2C9gUVOcTsb3vsqp3L1SX9kWq7T1Rkh4=; b=J03tice6Qt2/4eAqR0q0Mh6cnn hVfuY6+0KDysD1Ehv9YDikZROlfq+e0/EE+hryC79mcpsXNwGD2sXpOTJi5R6Mi0kNkzwU5DDPaZ0 gGzeu6yi6Afd2SLjtGTFbMtxC95J1TsfY8QCREQ2VOVnS+cy+8KMOdEAjNvIHwwiWAwFxbuxIjxmo r4YBHXrgAQ+OXQRjK7F1kb80szjTxi2e0CfGxL3md9IjeNrJQAPQRmebjnbPO5nTS8TwtTfZf4Oay YPHfB3HKhYwstdKdca/JzTOowUvvECE9sUK5uUQE9JDeCUlQYkbLCy4BP29LBvgmbtjYpOq0EQOxC TrATRenQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uC83K-00000009l5m-06rE; Tue, 06 May 2025 02:29:02 +0000 Received: from tor.source.kernel.org ([2600:3c04:e001:324:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uC4lP-00000008v5I-1mIF for linux-um@lists.infradead.org; Mon, 05 May 2025 22:58:19 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 06DB7629CA; Mon, 5 May 2025 22:57:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B82F2C4CEEE; Mon, 5 May 2025 22:58:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1746485898; bh=o6vPQm8ORAMEIjP7fhptjMtwSNq9nMRVlWGY99NWjZw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ckvpb0mO+BiWldk1mU6CORIigqhCbO4QLRDdfHhgHbhBdy4GbDq6mM9BGY/X4ZzGT iWp/GvYQNAC/76w6heje6A/b6+ugENNvSkrpKH1vaGGj1BOKOAVuHgjd8AeLjAAijQ 4NDwMAjvIsKp2jlJHuqZIIPDfZ7ohXMKKfp/d/yF3oB2SNU3gMh9wS49NWMyby8dbn fxcZ5Q7g9w9YlMvpaIE3OpvcU1Ch1AWnLFqZOMPRqpn8V3gST8IkoI+09/RUn2MoN0 JLf2rdJaFJTDdsiXESLwOzhzlCG+se+s09ZmUVi7EyLM4Tm/w3KYFqW7UQhcfvpcRS XzUwrFUjwKJJA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Benjamin Berg , Johannes Berg , Sasha Levin , richard@nod.at, anton.ivanov@cambridgegreys.com, johannes@sipsolutions.net, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, linux-um@lists.infradead.org Subject: [PATCH AUTOSEL 6.6 054/294] um: Store full CSGSFS and SS register from mcontext Date: Mon, 5 May 2025 18:52:34 -0400 Message-Id: <20250505225634.2688578-54-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250505225634.2688578-1-sashal@kernel.org> References: <20250505225634.2688578-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.6.89 Content-Transfer-Encoding: 8bit X-BeenThere: linux-um@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-um" Errors-To: linux-um-bounces+linux-um=archiver.kernel.org@lists.infradead.org From: Benjamin Berg [ Upstream commit cef721e0d53d2b64f2ba177c63a0dfdd7c0daf17 ] Doing this allows using registers as retrieved from an mcontext to be pushed to a process using PTRACE_SETREGS. It is not entirely clear to me why CSGSFS was masked. Doing so creates issues when using the mcontext as process state in seccomp and simply copying the register appears to work perfectly fine for ptrace. Signed-off-by: Benjamin Berg Link: https://patch.msgid.link/20250224181827.647129-2-benjamin@sipsolutions.net Signed-off-by: Johannes Berg Signed-off-by: Sasha Levin --- arch/x86/um/os-Linux/mcontext.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/arch/x86/um/os-Linux/mcontext.c b/arch/x86/um/os-Linux/mcontext.c index 49c3744cac371..81b9d1f9f4e68 100644 --- a/arch/x86/um/os-Linux/mcontext.c +++ b/arch/x86/um/os-Linux/mcontext.c @@ -26,7 +26,6 @@ void get_regs_from_mc(struct uml_pt_regs *regs, mcontext_t *mc) COPY(RIP); COPY2(EFLAGS, EFL); COPY2(CS, CSGSFS); - regs->gp[CS / sizeof(unsigned long)] &= 0xffff; - regs->gp[CS / sizeof(unsigned long)] |= 3; + regs->gp[SS / sizeof(unsigned long)] = mc->gregs[REG_CSGSFS] >> 48; #endif } -- 2.39.5