lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <11900179483116-git-send-email-avi@qumranet.com>
Date:	Mon, 17 Sep 2007 10:31:36 +0200
From:	Avi Kivity <avi@...ranet.com>
To:	kvm-devel@...ts.sourceforge.net
Cc:	linux-kernel@...r.kernel.org, Avi Kivity <avi@...ranet.com>
Subject: [PATCH 054/104] KVM: Close minor race in signal handling

We need to check for signals inside the critical section, otherwise a
signal can be sent which we will not notice.  Also move the check
before entry, so that if the signal happens before the first entry,
we exit immediately instead of waiting for something to happen to the
guest.

Signed-off-by: Avi Kivity <avi@...ranet.com>
---
 drivers/kvm/svm.c |   19 ++++++++++---------
 drivers/kvm/vmx.c |   23 ++++++++++++-----------
 2 files changed, 22 insertions(+), 20 deletions(-)

diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c
index e3c6d89..cc674bf 100644
--- a/drivers/kvm/svm.c
+++ b/drivers/kvm/svm.c
@@ -1398,11 +1398,19 @@ again:
 	if (unlikely(r))
 		return r;
 
+	clgi();
+
+	if (signal_pending(current)) {
+		stgi();
+		++vcpu->stat.signal_exits;
+		post_kvm_run_save(svm, kvm_run);
+		kvm_run->exit_reason = KVM_EXIT_INTR;
+		return -EINTR;
+	}
+
 	if (!vcpu->mmio_read_completed)
 		do_interrupt_requests(svm, kvm_run);
 
-	clgi();
-
 	vcpu->guest_mode = 1;
 	if (vcpu->requests)
 		if (test_and_clear_bit(KVM_TLB_FLUSH, &vcpu->requests))
@@ -1582,13 +1590,6 @@ again:
 
 	r = handle_exit(svm, kvm_run);
 	if (r > 0) {
-		if (signal_pending(current)) {
-			++vcpu->stat.signal_exits;
-			post_kvm_run_save(svm, kvm_run);
-			kvm_run->exit_reason = KVM_EXIT_INTR;
-			return -EINTR;
-		}
-
 		if (dm_request_for_irq_injection(svm, kvm_run)) {
 			++vcpu->stat.request_irq_exits;
 			post_kvm_run_save(svm, kvm_run);
diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index 906d4fa..a9b4cb5 100644
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -2066,9 +2066,6 @@ again:
 
 	preempt_disable();
 
-	if (!vcpu->mmio_read_completed)
-		do_interrupt_requests(vcpu, kvm_run);
-
 	vmx_save_host_state(vmx);
 	kvm_load_guest_fpu(vcpu);
 
@@ -2079,6 +2076,18 @@ again:
 
 	local_irq_disable();
 
+	if (signal_pending(current)) {
+		local_irq_enable();
+		preempt_enable();
+		r = -EINTR;
+		kvm_run->exit_reason = KVM_EXIT_INTR;
+		++vcpu->stat.signal_exits;
+		goto out;
+	}
+
+	if (!vcpu->mmio_read_completed)
+		do_interrupt_requests(vcpu, kvm_run);
+
 	vcpu->guest_mode = 1;
 	if (vcpu->requests)
 		if (test_and_clear_bit(KVM_TLB_FLUSH, &vcpu->requests))
@@ -2227,14 +2236,6 @@ again:
 
 	r = kvm_handle_exit(kvm_run, vcpu);
 	if (r > 0) {
-		/* Give scheduler a change to reschedule. */
-		if (signal_pending(current)) {
-			r = -EINTR;
-			kvm_run->exit_reason = KVM_EXIT_INTR;
-			++vcpu->stat.signal_exits;
-			goto out;
-		}
-
 		if (dm_request_for_irq_injection(vcpu, kvm_run)) {
 			r = -EINTR;
 			kvm_run->exit_reason = KVM_EXIT_INTR;
-- 
1.5.3

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ