Home Home > GIT Browse
summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorPaolo Bonzini <pbonzini@redhat.com>2016-06-01 14:09:21 +0200
committerSasha Levin <sasha.levin@oracle.com>2016-06-19 23:47:42 -0400
commit9a579331430c2cebb99488f664a736654988532d (patch)
tree4764d72ebd035ad6df5a6d3783108807a4a666c8
parentb0f8d64a5f8aa3dceff51bf83b58378627bf27d9 (diff)
KVM: irqfd: fix NULL pointer dereference in kvm_irq_map_gsi
[ Upstream commit c622a3c21ede892e370b56e1ceb9eb28f8bbda6b ] Found by syzkaller: BUG: unable to handle kernel NULL pointer dereference at 0000000000000120 IP: [<ffffffffa0797202>] kvm_irq_map_gsi+0x12/0x90 [kvm] PGD 6f80b067 PUD b6535067 PMD 0 Oops: 0000 [#1] SMP CPU: 3 PID: 4988 Comm: a.out Not tainted 4.4.9-300.fc23.x86_64 #1 [...] Call Trace: [<ffffffffa0795f62>] irqfd_update+0x32/0xc0 [kvm] [<ffffffffa0796c7c>] kvm_irqfd+0x3dc/0x5b0 [kvm] [<ffffffffa07943f4>] kvm_vm_ioctl+0x164/0x6f0 [kvm] [<ffffffff81241648>] do_vfs_ioctl+0x298/0x480 [<ffffffff812418a9>] SyS_ioctl+0x79/0x90 [<ffffffff817a1062>] tracesys_phase2+0x84/0x89 Code: b5 71 a7 e0 5b 41 5c 41 5d 5d f3 c3 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 55 48 8b 8f 10 2e 00 00 31 c0 48 89 e5 <39> 91 20 01 00 00 76 6a 48 63 d2 48 8b 94 d1 28 01 00 00 48 85 RIP [<ffffffffa0797202>] kvm_irq_map_gsi+0x12/0x90 [kvm] RSP <ffff8800926cbca8> CR2: 0000000000000120 Testcase: #include <unistd.h> #include <sys/syscall.h> #include <string.h> #include <stdint.h> #include <linux/kvm.h> #include <fcntl.h> #include <sys/ioctl.h> long r[26]; int main() { memset(r, -1, sizeof(r)); r[2] = open("/dev/kvm", 0); r[3] = ioctl(r[2], KVM_CREATE_VM, 0); struct kvm_irqfd ifd; ifd.fd = syscall(SYS_eventfd2, 5, 0); ifd.gsi = 3; ifd.flags = 2; ifd.resamplefd = ifd.fd; r[25] = ioctl(r[3], KVM_IRQFD, &ifd); return 0; } Reported-by: Dmitry Vyukov <dvyukov@google.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
-rw-r--r--virt/kvm/irqchip.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/virt/kvm/irqchip.c b/virt/kvm/irqchip.c
index 7f256f31df10..da39ee32005f 100644
--- a/virt/kvm/irqchip.c
+++ b/virt/kvm/irqchip.c
@@ -51,7 +51,7 @@ int kvm_irq_map_gsi(struct kvm *kvm,
irq_rt = srcu_dereference_check(kvm->irq_routing, &kvm->irq_srcu,
lockdep_is_held(&kvm->irq_lock));
- if (gsi < irq_rt->nr_rt_entries) {
+ if (irq_rt && gsi < irq_rt->nr_rt_entries) {
hlist_for_each_entry(e, &irq_rt->map[gsi], link) {
entries[n] = *e;
++n;