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 E0E4E3AC5BD; Mon, 5 May 2025 23:19:03 +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=1746487145; cv=none; b=H/dV/xTfqGr/moGzcZ9d9e/7NeQN3KS0hhb5+ulm/3hvCuGFcnNLanSW4I+o6KquL79IpYGp1xXiHmuXCPesWFu4Rb4HhUYRsbByPvsaEjINkB20a56lEuJHcG6b671qZZJKnvGj+X/PDisKg9JXh9Nvb0btW96KR7LR9ldSQkw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746487145; c=relaxed/simple; bh=o6vPQm8ORAMEIjP7fhptjMtwSNq9nMRVlWGY99NWjZw=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=Xa/cXbGA9fhdIV8nY2Q2IDEKt2mQlfOLHYYdogISreAY63NoYb+A3EyBNATW2t1FW6LcnRdsQmqMu3t9zW8Cuc6lKII6NqZ9lIy8Mz714iXQXI7EdZ+KCKVpX76+vqBs6g2dqma0nvuKGKZb267d8UAzPGnPGCYrrEH47SmJ4I4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gSrc4YGQ; 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="gSrc4YGQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8D5F2C4CEEE; Mon, 5 May 2025 23:19:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1746487143; bh=o6vPQm8ORAMEIjP7fhptjMtwSNq9nMRVlWGY99NWjZw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gSrc4YGQXNcraedU3V9MzwlkEmcOiZF+MaSYYjotDqktpWMZFN++hOvTMeNeFmfzh 2yA1SDlJ8HruqWDIzeSgNZvtt28MIK/m6tI1AakTe/KaW0Ot9soVf7kaFjJ4E+xdF0 OE5FwOBc1uUzOLtl5W32o/QBSbXs8tZJaXiyco81Iw5TAYC7LGEWOtkXakoHTAnBpF SBQGUL4GQBLvgSOD+j4qWsmY11aR/z6at+dMXoFe4eKG59COieSRzHO8REmMNLl6gQ JHKbfsn7H5L7e7VLUe8vo1Lk5xab6OR1NgNOdW92+a3K+DDAkLI6I2WrGwxd7tvLVu oKDXQOTTM4a2Q== 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 5.10 022/114] um: Store full CSGSFS and SS register from mcontext Date: Mon, 5 May 2025 19:16:45 -0400 Message-Id: <20250505231817.2697367-22-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250505231817.2697367-1-sashal@kernel.org> References: <20250505231817.2697367-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 5.10.237 Content-Transfer-Encoding: 8bit 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