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 A5651280A37; Mon, 5 May 2025 22:58:18 +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=1746485898; cv=none; b=lYOfNu8v03P/L1jQZvLATCAi8DEGIacaMA1tEEHTf+dcaMkkb4DK6aE8z585M9kq3s/MSZH2aoyERIx0XfOsrTmOWYFc5M+EyMUvcNfuyVZQqcz5m3oKUleeGL8M5xLxyto/gngySPIolSH8W5GGjm5wZk4RmAJzn+G7EwpPtr4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746485898; c=relaxed/simple; bh=o6vPQm8ORAMEIjP7fhptjMtwSNq9nMRVlWGY99NWjZw=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=bYomrnqa33OLYKJjNqiUlfdlgbIeb1lMfqMzJnS/DYBbDb8E1v/2bqrxMFfrv6k99Xzbx1Zzu6Kwpnw0HGF6834Bc2pFHUesgxUS1rnJtseggxeQD9mWhnOv16rhG0y6IIhDDeQUla+sF+qauaRZumtl5/yaHYNUyytlWCmFnn8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ckvpb0mO; 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="ckvpb0mO" 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> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.6.89 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