From 838e3893300a078ef12aa1d8d8c2336df259d2e0 Mon Sep 17 00:00:00 2001 From: Andreas Wellving Date: Mon, 4 Feb 2019 13:23:53 +0100 Subject: KVM: CVE-2018-19407 KVM: X86: Fix scan ioapic use-before-initialization References: https://nvd.nist.gov/vuln/detail/CVE-2018-19407 https://lkml.org/lkml/2018/11/20/580 Change-Id: I25db67cd123956dbcf240a99f316e914c283d0e2 Signed-off-by: Andreas Wellving --- patches/cve/4.14.x.scc | 1 + ...Fix-scan-ioapic-use-before-initialization.patch | 112 +++++++++++++++++++++ 2 files changed, 113 insertions(+) create mode 100644 patches/cve/CVE-2018-19407-KVM-X86-Fix-scan-ioapic-use-before-initialization.patch diff --git a/patches/cve/4.14.x.scc b/patches/cve/4.14.x.scc index f47c792..9a53416 100644 --- a/patches/cve/4.14.x.scc +++ b/patches/cve/4.14.x.scc @@ -10,3 +10,4 @@ patch CVE-2018-14610-btrfs-Check-that-each-block-group-has-corresponding-.patch patch CVE-2018-14611-btrfs-validate-type-when-reading-a-chunk.patch patch CVE-2018-14614-f2fs-fix-to-do-sanity-check-with-cp_pack_start_sum.patch patch CVE-2018-18690-xfs-don-t-fail-when-converting-shortform-attr-to-lon.patch +patch CVE-2018-19407-KVM-X86-Fix-scan-ioapic-use-before-initialization.patch diff --git a/patches/cve/CVE-2018-19407-KVM-X86-Fix-scan-ioapic-use-before-initialization.patch b/patches/cve/CVE-2018-19407-KVM-X86-Fix-scan-ioapic-use-before-initialization.patch new file mode 100644 index 0000000..55cc7e4 --- /dev/null +++ b/patches/cve/CVE-2018-19407-KVM-X86-Fix-scan-ioapic-use-before-initialization.patch @@ -0,0 +1,112 @@ +From 83f00ab9a7c03e9f1410727d985b7fe9473002e1 Mon Sep 17 00:00:00 2001 +From: Wanpeng Li +Date: Tue, 20 Nov 2018 16:34:18 +0800 +Subject: [PATCH] KVM: X86: Fix scan ioapic use-before-initialization +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +commit e97f852fd4561e77721bb9a4e0ea9d98305b1e93 upstream. + +Reported by syzkaller: + + BUG: unable to handle kernel NULL pointer dereference at 00000000000001c8 + PGD 80000003ec4da067 P4D 80000003ec4da067 PUD 3f7bfa067 PMD 0 + Oops: 0000 [#1] PREEMPT SMP PTI + CPU: 7 PID: 5059 Comm: debug Tainted: G OE 4.19.0-rc5 #16 + RIP: 0010:__lock_acquire+0x1a6/0x1990 + Call Trace: + lock_acquire+0xdb/0x210 + _raw_spin_lock+0x38/0x70 + kvm_ioapic_scan_entry+0x3e/0x110 [kvm] + vcpu_enter_guest+0x167e/0x1910 [kvm] + kvm_arch_vcpu_ioctl_run+0x35c/0x610 [kvm] + kvm_vcpu_ioctl+0x3e9/0x6d0 [kvm] + do_vfs_ioctl+0xa5/0x690 + ksys_ioctl+0x6d/0x80 + __x64_sys_ioctl+0x1a/0x20 + do_syscall_64+0x83/0x6e0 + entry_SYSCALL_64_after_hwframe+0x49/0xbe + +The reason is that the testcase writes hyperv synic HV_X64_MSR_SINT6 msr +and triggers scan ioapic logic to load synic vectors into EOI exit bitmap. +However, irqchip is not initialized by this simple testcase, ioapic/apic +objects should not be accessed. +This can be triggered by the following program: + + #define _GNU_SOURCE + + #include + #include + #include + #include + #include + #include + #include + #include + + uint64_t r[3] = {0xffffffffffffffff, 0xffffffffffffffff, 0xffffffffffffffff}; + + int main(void) + { + syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0); + long res = 0; + memcpy((void*)0x20000040, "/dev/kvm", 9); + res = syscall(__NR_openat, 0xffffffffffffff9c, 0x20000040, 0, 0); + if (res != -1) + r[0] = res;Backport + res = syscall(__NR_ioctl, r[0], 0xae01, 0); + if (res != -1) + r[1] = res; + res = syscall(__NR_ioctl, r[1], 0xae41, 0); + if (res != -1) + r[2] = res; + memcpy( + (void*)0x20000080, + "\x01\x00\x00\x00\x00\x5b\x61\xbb\x96\x00\x00\x40\x00\x00\x00\x00\x01\x00" + "\x08\x00\x00\x00\x00\x00\x0b\x77\xd1\x78\x4d\xd8\x3a\xed\xb1\x5c\x2e\x43" + "\xaa\x43\x39\xd6\xff\xf5\xf0\xa8\x98\xf2\x3e\x37\x29\x89\xde\x88\xc6\x33" + "\xfc\x2a\xdb\xb7\xe1\x4c\xac\x28\x61\x7b\x9c\xa9\xbc\x0d\xa0\x63\xfe\xfe" + "\xe8\x75\xde\xdd\x19\x38\xdc\x34\xf5\xec\x05\xfd\xeb\x5d\xed\x2e\xaf\x22" + "\xfa\xab\xb7\xe4\x42\x67\xd0\xaf\x06\x1c\x6a\x35\x67\x10\x55\xcb", + 106); + syscall(__NR_ioctl, r[2], 0x4008ae89, 0x20000080); + syscall(__NR_ioctl, r[2], 0xae80, 0); + return 0; + } + +This patch fixes it by bailing out scan ioapic if ioapic is not initialized in +kernel. + +CVE: CVE-2018-19407 +Upstream-Status: Backport + +Reported-by: Wei Wu +Cc: Paolo Bonzini +Cc: Radim Krčmář +Cc: Wei Wu +Signed-off-by: Wanpeng Li +Cc: stable@vger.kernel.org +Signed-off-by: Paolo Bonzini +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Andreas Wellving +--- + arch/x86/kvm/x86.c | 3 ++- + 1 file changed, 2 insertions(+), 1 deletion(-) + +diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c +index 7c4d02dba110..f24329659bea 100644 +--- a/arch/x86/kvm/x86.c ++++ b/arch/x86/kvm/x86.c +@@ -6885,7 +6885,8 @@ static void vcpu_scan_ioapic(struct kvm_vcpu *vcpu) + else { + if (kvm_x86_ops->sync_pir_to_irr && vcpu->arch.apicv_active) + kvm_x86_ops->sync_pir_to_irr(vcpu); +- kvm_ioapic_scan_entry(vcpu, vcpu->arch.ioapic_handled_vectors); ++ if (ioapic_in_kernel(vcpu->kvm)) ++ kvm_ioapic_scan_entry(vcpu, vcpu->arch.ioapic_handled_vectors); + } + bitmap_or((ulong *)eoi_exit_bitmap, vcpu->arch.ioapic_handled_vectors, + vcpu_to_synic(vcpu)->vec_bitmap, 256); +-- +2.19.2 -- cgit v1.2.3-54-g00ecf