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 95AB3299AA0; Mon, 5 May 2025 22:19:15 +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=1746483555; cv=none; b=rpSjiMHN++t96WecvxySRCr+yY8bf4HJo5uHRuTiJEvjkbQHmqQSkEYS9shImrqn2XJJF4nuKLDMUh/Dfj1qJOfRGsG63/o8cvP9CGQnHyyNXARm19PWYuogyOH84AG2S9mrQrLdEDPRW6bL6EetFnSrJbkMXlxILm5hQ/sRPBk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746483555; c=relaxed/simple; bh=9weVegpYXoQ9xLpHIcIuPVDiPw1gpg0ij9gTTrw3cNE=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=LdGYcCwC+2kqFv952eLhOMO/o8dC9bpkjgfklPW+DZE7cWOxEmmXn4e9Lh4hOapVC7rM4ZRfW2lW3OddhJBM7PoGbnUv+5orQ8lQGkBlLM8Q804BvLJJRVZDdwqKJLpxacYEwyex2fdau7OXYFNF/0z1CxMmM3OuKaJXOFLS2Ug= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=qNulUB5A; 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="qNulUB5A" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 09C3DC4CEEE; Mon, 5 May 2025 22:19:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1746483555; bh=9weVegpYXoQ9xLpHIcIuPVDiPw1gpg0ij9gTTrw3cNE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qNulUB5AU7oz9HvkwOwQ5rAhGoIE+OrXEy0iQgktSpwJNv5uow5EKgRQOx6+Mfeyz H5nrD5zZKOqaKLJsDNoF1X7I6fTQ90gCDChzoLPgMfTftMBnuRVuu9WFMJoE5bHHdS yThXZMzUDgSWjBIahFzgtk1Qd1YnMevDR5vsU9PUFl4U4OmwaR0s1IzDaL2b27pSzj Qoo7i/e4XDxOod9hFwuPkbRNt3dtP+LP3QGqsXvFOTzLwsjOoIU0jEnzR9HeRMhuT3 YW4qyCGcxoEac7PnUw4+obMiJQz/9ApR3MjLgE7D/B2pW+VkwHaKyhzSlcfLlIexwX YMu+KOy7a++Kw== 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 6.14 113/642] um: Store full CSGSFS and SS register from mcontext Date: Mon, 5 May 2025 18:05:29 -0400 Message-Id: <20250505221419.2672473-113-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250505221419.2672473-1-sashal@kernel.org> References: <20250505221419.2672473-1-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 6.14.5 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 e80ab7d281177..1b0d95328b2c7 100644 --- a/arch/x86/um/os-Linux/mcontext.c +++ b/arch/x86/um/os-Linux/mcontext.c @@ -27,7 +27,6 @@ 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