From patchwork Fri Dec 15 01:40:50 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Wanpeng Li X-Patchwork-Id: 10113513 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 959D4602B3 for ; Fri, 15 Dec 2017 01:41:09 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8843829D3D for ; Fri, 15 Dec 2017 01:41:09 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 7D10129DC5; Fri, 15 Dec 2017 01:41:09 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, FREEMAIL_FROM, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 078FF29D3D for ; Fri, 15 Dec 2017 01:41:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754596AbdLOBk5 (ORCPT ); Thu, 14 Dec 2017 20:40:57 -0500 Received: from mail-pg0-f65.google.com ([74.125.83.65]:44620 "EHLO mail-pg0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754538AbdLOBkz (ORCPT ); Thu, 14 Dec 2017 20:40:55 -0500 Received: by mail-pg0-f65.google.com with SMTP id j9so4702318pgc.11; Thu, 14 Dec 2017 17:40:55 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=tPNeFVX1in0kvFMsgFXZ0CjH0SMfE+2OFQ3c8fM9pvc=; b=DKVT11aE2ngSEcnZsHhVcW81NLbQgv18Ulm//zZuVrN7AMvbdb7GgRhqZehLJwgWdz 9kEPNWxSKO5LnjYKENIutx5KmG58DKYIENX/hmrctYDjSCp7qP+vzg1VGzxQHaaFM8hq eHjB7pLr1NKgoZX2/Ul26VsQ+8EStGjarWzSfaFt6wPnFT6oQ7Va7lR2OaWMm2sAUPsG L8ntZQ/LZLK7sSfBvEGw605EG0Je5uSP+hUIZwFI09Fuiu5P6np7NVMZxm/BzH3hqk/1 MIesVboKcyg0ZIzAB8tL9Mz3eKRt9S+wsyzSEkUHztKPVz9CKMOWZWjigCC7ralRQRCE rDcw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=tPNeFVX1in0kvFMsgFXZ0CjH0SMfE+2OFQ3c8fM9pvc=; b=iC201KfKuHgyoAOHIxaQBciTkgw8odPusDhTi07+xJKBT0S/FCIgqN6OinCXhaG/VY OIAtSAHrM0oq8WHby23UGYPuudL98BaS2tTGyXnCzSBCMk2dZg4Ai7aIuyzJ0ckyWaA8 Z0wc0qxKw226URSw250LFnyu9ghQlZMMeHMH7Yw3WgptW0FG6lLJEEb3ABbgI9PnS1Hl Mim8IMAFsasTwQgPvm9pQMc1x0PcmfKfXT5eaVYCm5MsiZOyns4sqXUaxr1KLgxB7Yo9 knnXu3/wzEUm4dRFrCU4WXHWJLYEvy60heEJqqnw80z57BWqoa8jby0WlNyoQ84/LtcL qwVw== X-Gm-Message-State: AKGB3mIL40oZJNeBKlsHHHu2cPE5iUYXTLQC2rwbCLV/AzJaZBv4I5So yVwztL+KOVYgJzdKYbNjFTpsaA== X-Google-Smtp-Source: ACJfBos0Id8TTzSUYlbYDzwrfUFDidtJ8sckUxV2RBEaBJGdXBpRwgVqrSoYnkWvIthxBRVF8lTwKQ== X-Received: by 10.159.214.134 with SMTP id n6mr11751214plp.47.1513302054817; Thu, 14 Dec 2017 17:40:54 -0800 (PST) Received: from localhost ([203.205.141.123]) by smtp.gmail.com with ESMTPSA id i85sm10019791pfi.54.2017.12.14.17.40.53 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 14 Dec 2017 17:40:54 -0800 (PST) From: Wanpeng Li X-Google-Original-From: Wanpeng Li To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , Wanpeng Li , Marc Zyngier , Christoffer Dall Subject: [PATCH v4] KVM: Fix stack-out-of-bounds read in write_mmio Date: Thu, 14 Dec 2017 17:40:50 -0800 Message-Id: <1513302050-14253-1-git-send-email-wanpeng.li@hotmail.com> X-Mailer: git-send-email 2.7.4 MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Wanpeng Li Reported by syzkaller: BUG: KASAN: stack-out-of-bounds in write_mmio+0x11e/0x270 [kvm] Read of size 8 at addr ffff8803259df7f8 by task syz-executor/32298 CPU: 6 PID: 32298 Comm: syz-executor Tainted: G OE 4.15.0-rc2+ #18 Hardware name: LENOVO ThinkCentre M8500t-N000/SHARKBAY, BIOS FBKTC1AUS 02/16/2016 Call Trace: dump_stack+0xab/0xe1 print_address_description+0x6b/0x290 kasan_report+0x28a/0x370 write_mmio+0x11e/0x270 [kvm] emulator_read_write_onepage+0x311/0x600 [kvm] emulator_read_write+0xef/0x240 [kvm] emulator_fix_hypercall+0x105/0x150 [kvm] em_hypercall+0x2b/0x80 [kvm] x86_emulate_insn+0x2b1/0x1640 [kvm] x86_emulate_instruction+0x39a/0xb90 [kvm] handle_exception+0x1b4/0x4d0 [kvm_intel] vcpu_enter_guest+0x15a0/0x2640 [kvm] kvm_arch_vcpu_ioctl_run+0x549/0x7d0 [kvm] kvm_vcpu_ioctl+0x479/0x880 [kvm] do_vfs_ioctl+0x142/0x9a0 SyS_ioctl+0x74/0x80 entry_SYSCALL_64_fastpath+0x23/0x9a The path of patched vmmcall will patch 3 bytes opcode 0F 01 C1(vmcall) to the guest memory, however, write_mmio tracepoint always prints 8 bytes through *(u64 *)val since kvm splits the mmio access into 8 bytes. This can result in stack-out-of-bounds read due to access the extra 5 bytes. This patch fixes it by just accessing the bytes which we operates on. Before patch: syz-executor-5567 [007] .... 51370.561696: kvm_mmio: mmio write len 3 gpa 0x10 val 0x1ffff10077c1010f After patch: syz-executor-13416 [002] .... 51302.299573: kvm_mmio: mmio write len 3 gpa 0x10 val 0xc1010f Reported-by: Dmitry Vyukov Cc: Paolo Bonzini Cc: Radim Krčmář Cc: Marc Zyngier Cc: Christoffer Dall Signed-off-by: Wanpeng Li Reviewed-by: Darren Kenny Reviewed-by: Marc Zyngier Tested-by: Marc Zyngier --- v3 -> v4: * fix the arm tracepoint v2 -> v3: * fix sparse warning v1 -> v2: * do the memcpy in kvm_mmio tracepoint arch/x86/kvm/x86.c | 8 ++++---- include/trace/events/kvm.h | 6 ++++-- virt/kvm/arm/mmio.c | 6 +++--- 3 files changed, 11 insertions(+), 9 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 0f82e2c..c7071e7 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4456,7 +4456,7 @@ static int vcpu_mmio_read(struct kvm_vcpu *vcpu, gpa_t addr, int len, void *v) addr, n, v)) && kvm_io_bus_read(vcpu, KVM_MMIO_BUS, addr, n, v)) break; - trace_kvm_mmio(KVM_TRACE_MMIO_READ, n, addr, *(u64 *)v); + trace_kvm_mmio(KVM_TRACE_MMIO_READ, n, addr, v); handled += n; addr += n; len -= n; @@ -4715,7 +4715,7 @@ static int read_prepare(struct kvm_vcpu *vcpu, void *val, int bytes) { if (vcpu->mmio_read_completed) { trace_kvm_mmio(KVM_TRACE_MMIO_READ, bytes, - vcpu->mmio_fragments[0].gpa, *(u64 *)val); + vcpu->mmio_fragments[0].gpa, val); vcpu->mmio_read_completed = 0; return 1; } @@ -4737,14 +4737,14 @@ static int write_emulate(struct kvm_vcpu *vcpu, gpa_t gpa, static int write_mmio(struct kvm_vcpu *vcpu, gpa_t gpa, int bytes, void *val) { - trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, bytes, gpa, *(u64 *)val); + trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, bytes, gpa, val); return vcpu_mmio_write(vcpu, gpa, bytes, val); } static int read_exit_mmio(struct kvm_vcpu *vcpu, gpa_t gpa, void *val, int bytes) { - trace_kvm_mmio(KVM_TRACE_MMIO_READ_UNSATISFIED, bytes, gpa, 0); + trace_kvm_mmio(KVM_TRACE_MMIO_READ_UNSATISFIED, bytes, gpa, NULL); return X86EMUL_IO_NEEDED; } diff --git a/include/trace/events/kvm.h b/include/trace/events/kvm.h index e4b0b8e..dfd2170 100644 --- a/include/trace/events/kvm.h +++ b/include/trace/events/kvm.h @@ -211,7 +211,7 @@ TRACE_EVENT(kvm_ack_irq, { KVM_TRACE_MMIO_WRITE, "write" } TRACE_EVENT(kvm_mmio, - TP_PROTO(int type, int len, u64 gpa, u64 val), + TP_PROTO(int type, int len, u64 gpa, void *val), TP_ARGS(type, len, gpa, val), TP_STRUCT__entry( @@ -225,7 +225,9 @@ TRACE_EVENT(kvm_mmio, __entry->type = type; __entry->len = len; __entry->gpa = gpa; - __entry->val = val; + __entry->val = 0; + if (val) + memcpy(&__entry->val, val, min(8, len)); ), TP_printk("mmio %s len %u gpa 0x%llx val 0x%llx", diff --git a/virt/kvm/arm/mmio.c b/virt/kvm/arm/mmio.c index b6e715f..dac7ceb 100644 --- a/virt/kvm/arm/mmio.c +++ b/virt/kvm/arm/mmio.c @@ -112,7 +112,7 @@ int kvm_handle_mmio_return(struct kvm_vcpu *vcpu, struct kvm_run *run) } trace_kvm_mmio(KVM_TRACE_MMIO_READ, len, run->mmio.phys_addr, - data); + &data); data = vcpu_data_host_to_guest(vcpu, data, len); vcpu_set_reg(vcpu, vcpu->arch.mmio_decode.rt, data); } @@ -182,14 +182,14 @@ int io_mem_abort(struct kvm_vcpu *vcpu, struct kvm_run *run, data = vcpu_data_guest_to_host(vcpu, vcpu_get_reg(vcpu, rt), len); - trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, len, fault_ipa, data); + trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, len, fault_ipa, &data); kvm_mmio_write_buf(data_buf, len, data); ret = kvm_io_bus_write(vcpu, KVM_MMIO_BUS, fault_ipa, len, data_buf); } else { trace_kvm_mmio(KVM_TRACE_MMIO_READ_UNSATISFIED, len, - fault_ipa, 0); + fault_ipa, NULL); ret = kvm_io_bus_read(vcpu, KVM_MMIO_BUS, fault_ipa, len, data_buf);