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authorJustin M. Forbes <jforbes@fedoraproject.org>2018-06-11 16:15:37 -0500
committerJustin M. Forbes <jforbes@fedoraproject.org>2018-06-11 16:15:37 -0500
commit088f35853be6303ddf60d321ef5f4ef44fd636cf (patch)
tree2af26bceece53619b42f47c00615f02a2df27237
parent659cba17dc6ad120c1b4909de6ee2fc3469eccaf (diff)
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Fix CVE-2018-10853 (rhbz 1589890 1589892)
-rw-r--r--kernel.spec6
-rw-r--r--kvm-x86-Check-CPL-in-segmented_write_std.patch43
2 files changed, 49 insertions, 0 deletions
diff --git a/kernel.spec b/kernel.spec
index a4e0f98c7..455b46d9d 100644
--- a/kernel.spec
+++ b/kernel.spec
@@ -668,6 +668,9 @@ Patch513: ext4-correctly-handle-a-zero-length-xattr-with-a-non.patch
# https://www.spinics.net/lists/kernel/msg2818652.html applies cleanly to 4.17
Patch514: libata-Drop-SanDisk-SD7UB3Q-G1001-NOLPM-quirk.patch
+# CVE-2018-10853 rhbz 1589890 1589892
+Patch515: kvm-x86-Check-CPL-in-segmented_write_std.patch
+
# END OF PATCH DEFINITIONS
%endif
@@ -1918,6 +1921,9 @@ fi
#
#
%changelog
+* Mon Jun 11 2018 Justin M. Forbes <jforbes@fedoraproject.org>
+- Fix CVE-2018-10853 (rhbz 1589890 1589892)
+
* Tue Jun 05 2018 Jeremy Cline <jeremy@jcline.org>
- Enable CONFIG_SCSI_DH on s390x (rhbz 1586189)
diff --git a/kvm-x86-Check-CPL-in-segmented_write_std.patch b/kvm-x86-Check-CPL-in-segmented_write_std.patch
new file mode 100644
index 000000000..a0447d31c
--- /dev/null
+++ b/kvm-x86-Check-CPL-in-segmented_write_std.patch
@@ -0,0 +1,43 @@
+From patchwork Tue Jun 5 20:04:16 2018
+Content-Type: text/plain; charset="utf-8"
+MIME-Version: 1.0
+Content-Transfer-Encoding: 7bit
+Subject: kvm: x86: Check CPL in segmented_write_std
+From: Bandan Das <bsd@redhat.com>
+X-Patchwork-Id: 10449159
+Message-Id: <jpgtvqhuhj3.fsf@linux.bootlegged.copy>
+To: kvm@vger.kernel.org
+Cc: Paolo Bonzini <pbonzini@redhat.com>,
+ Radim =?utf-8?B?S3LEjW3DocWZ?= <rkrcmar@redhat.com>,
+ Andy Lutomirski <luto@kernel.org>
+Date: Tue, 05 Jun 2018 16:04:16 -0400
+
+Certain instructions such as sgdt/sidt call segmented_write_std that
+doesn't propagate access correctly. As such, during userspace induced
+exception, the guest can incorrectly assume that the exception
+happened in the kernel and panic. The emulated write function
+segmented_write does seem to check access correctly.
+
+Reported-by: Andy Lutomirski <luto@kernel.org>
+Signed-off-by: Bandan Das <bsd@redhat.com>
+---
+ 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 71e7cda6d014..871265f6a35f 100644
+--- a/arch/x86/kvm/x86.c
++++ b/arch/x86/kvm/x86.c
+@@ -4824,10 +4824,11 @@ int kvm_write_guest_virt_system(struct x86_emulate_ctxt *ctxt,
+ struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
+ void *data = val;
+ int r = X86EMUL_CONTINUE;
++ u32 access = (kvm_x86_ops->get_cpl(vcpu) == 3) ? PFERR_USER_MASK : 0;
+
+ while (bytes) {
+ gpa_t gpa = vcpu->arch.walk_mmu->gva_to_gpa(vcpu, addr,
+- PFERR_WRITE_MASK,
++ access | PFERR_WRITE_MASK,
+ exception);
+ unsigned offset = addr & (PAGE_SIZE-1);
+ unsigned towrite = min(bytes, (unsigned)PAGE_SIZE - offset);