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 641131B29C1; Wed, 25 Sep 2024 11:41:35 +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=1727264495; cv=none; b=r1Me4Gjfs7PlI5xpYG0cVw2BM4wFKfEj08BqPgECcjtiiMhfeC8sWd6AP5JPvziZtsS8Of4Evu04GO5p2XofiL7zW/bjkc+AF2/EF0a+AGEkLcnJ8NF8T50pTXO7A1Xjti37orBFLYshDhwr9j9b0gcXM32rFtZzPYDGSf0nO1c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727264495; c=relaxed/simple; bh=ZYESEMUpErJ4ayIMU3hPmisXks/BT9GQ4NHkdXkKUlA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=jDobW30Yuzq/MTyQTRZY/tPNpJEafP/sL3qWCmskrp26Itr2mBTvoOgZHpeZYCFtLFxLWfZvYdczwVmZi/kzTF1dVYDFH5PjqHl+a2dAdqpLXShceHHLiKNIP8vHKsDUrYXBRI4fZFnR379JyJVBBz5XnZcbLJnbESbq/mrGwWg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=MmS3VT37; 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="MmS3VT37" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A062FC4CEC7; Wed, 25 Sep 2024 11:41:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1727264495; bh=ZYESEMUpErJ4ayIMU3hPmisXks/BT9GQ4NHkdXkKUlA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MmS3VT37yDiqgrF95kCX8+EF+kFBM4f6h+mNy5AzGQ3pfxtj4tBeXDq3utqOhL0CC rhEVKaz9wPRq4QMPphCE4fHGU+DBNuCtK5iDbqpza3yIQB7+1lpuRhb/PWmdymPVxi kdw1yQIojpwQnoKzm59yNBWti52sgqJ98IXc10l06t/yEgrQO4+VHixgz6u2aGrY1b dyDa/jrV4ApNa4JS6rxZfxq91mODFpqh8WlqPqfuW7vXebOwyUvxC6HNafcR8ZoV4N otRxmicITnbJPknZN0t/DjIlXA7vZ1qZe0qC9TR54Tn4MLaf9UYIgEmEADlyLEb7E+ qmmJrao2NDiZw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Aruna Ramakrishna , Thomas Gleixner , Sasha Levin , mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, rick.p.edgecombe@intel.com, hjl.tools@gmail.com Subject: [PATCH AUTOSEL 6.11 102/244] x86/pkeys: Restore altstack access in sigreturn() Date: Wed, 25 Sep 2024 07:25:23 -0400 Message-ID: <20240925113641.1297102-102-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240925113641.1297102-1-sashal@kernel.org> References: <20240925113641.1297102-1-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 6.11 Content-Transfer-Encoding: 8bit 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 8a94053c54446..ee9453891901b 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