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 2DE4015CAB for ; Tue, 8 Nov 2022 13:44:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8968FC4314D; Tue, 8 Nov 2022 13:44:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1667915070; bh=cn/D4miHMAh3UbaG+RCo2+HezdPgLbeL4bfdIIMI8Z0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=oxkzep9E61wqgZdJ+j+0BQ0BJeDg74WOHofdrcMN4QF1+Gt+9KlxKtiPCH+IwzBFV 3ihxHhw+E1HoPkIsYhgKj2qZ1EpVIpNECg1FRSCqRxrdDAVJD4y3yhfe+XerLyVO+5 OKOxqYWiWtelfXECMQN+Qb5ocGrNYUReyGJsFZmk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Maxim Levitsky , Paolo Bonzini Subject: [PATCH 4.14 34/40] KVM: x86: emulator: em_sysexit should update ctxt->mode Date: Tue, 8 Nov 2022 14:39:19 +0100 Message-Id: <20221108133329.621426523@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221108133328.351887714@linuxfoundation.org> References: <20221108133328.351887714@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Maxim Levitsky commit 5015bb89b58225f97df6ac44383e7e8c8662c8c9 upstream. SYSEXIT is one of the instructions that can change the processor mode, thus ctxt->mode should be updated after it. Note that this is likely a benign bug, because the only problematic mode change is from 32 bit to 64 bit which can lead to truncation of RIP, and it is not possible to do with sysexit, since sysexit running in 32 bit mode will be limited to 32 bit version. Signed-off-by: Maxim Levitsky Message-Id: <20221025124741.228045-11-mlevitsk@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/emulate.c | 1 + 1 file changed, 1 insertion(+) --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -2889,6 +2889,7 @@ static int em_sysexit(struct x86_emulate ops->set_segment(ctxt, ss_sel, &ss, 0, VCPU_SREG_SS); ctxt->_eip = rdx; + ctxt->mode = usermode; *reg_write(ctxt, VCPU_REGS_RSP) = rcx; return X86EMUL_CONTINUE;