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 A632B1D3653; Tue, 8 Oct 2024 13:15:19 +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=1728393319; cv=none; b=gKqG0lON80aa5DqU3vYE9tVS2ef/VyxJQG+7DHtGs8gy7NSvDf0Oy3MdOI5IQfof5lGiESji+blpiQeQQvDboENT15ebpdyhcI9KP1kgUcg/M6axfOr/sxmE5gjFkQCKrK8xsnd136zx71+tgaJrXV8f/GzvMmWokTImr+lQvgg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728393319; c=relaxed/simple; bh=BM+LgGwU71X9VPdp2HY+jHaiB7zWJPxTueMr0W66GE4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=S5hAqTA27p9oou45xarPgV65O5mjT4w8YSAuTeYXdgiU6hljvZYaryY7kpyjZDYVFH1qJYwnHz9ediUnQlX59HZ/E9Htx4Z7gtYXo2vo9V7jksir9q06uHPZJAlTK4GEHVJLoX4ZYI4jRnh5cw5BPvNjCqNqINvnnzEX8ZyJspU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=QQqINEbx; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="QQqINEbx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 29BC0C4CEC7; Tue, 8 Oct 2024 13:15:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1728393319; bh=BM+LgGwU71X9VPdp2HY+jHaiB7zWJPxTueMr0W66GE4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QQqINEbxQHENVA052MCOp/Jpm8EYHTwrWLxb+NekGNJ1Ar8HfW0OmmPkbmDrbXI8K tMyTQLsVQpU60Ba/mweAxbxbLXADV5crl8XdFmknjVrKO1mEyFaiwl0aceo6yqm+E7 dBqKSQdEF11lmwGv2etasauuuAU8aYG8b5ebkuW0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Aruna Ramakrishna , Thomas Gleixner , Sasha Levin Subject: [PATCH 6.6 116/386] x86/pkeys: Restore altstack access in sigreturn() Date: Tue, 8 Oct 2024 14:06:01 +0200 Message-ID: <20241008115634.007507328@linuxfoundation.org> X-Mailer: git-send-email 2.46.2 In-Reply-To: <20241008115629.309157387@linuxfoundation.org> References: <20241008115629.309157387@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Aruna Ramakrishna [ Upstream commit d10b554919d4cc8fa8fe2e95b57ad2624728c8e4 ] A process can disable access to the alternate signal stack by not enabling the altstack's PKEY in the PKRU register. Nevertheless, the kernel updates the PKRU temporarily for signal handling. However, in sigreturn(), restore_sigcontext() will restore the PKRU to the user-defined PKRU value. This will cause restore_altstack() to fail with a SIGSEGV as it needs read access to the altstack which is prohibited by the user-defined PKRU value. Fix this by restoring altstack before restoring PKRU. Signed-off-by: Aruna Ramakrishna Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/all/20240802061318.2140081-5-aruna.ramakrishna@oracle.com Signed-off-by: Sasha Levin --- arch/x86/kernel/signal_64.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/signal_64.c b/arch/x86/kernel/signal_64.c index 23d8aaf8d9fd1..449a6ed0b8c98 100644 --- a/arch/x86/kernel/signal_64.c +++ b/arch/x86/kernel/signal_64.c @@ -260,13 +260,13 @@ SYSCALL_DEFINE0(rt_sigreturn) set_current_blocked(&set); - if (!restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags)) + if (restore_altstack(&frame->uc.uc_stack)) goto badframe; - if (restore_signal_shadow_stack()) + if (!restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags)) goto badframe; - if (restore_altstack(&frame->uc.uc_stack)) + if (restore_signal_shadow_stack()) goto badframe; return regs->ax; -- 2.43.0