From: Paolo Bonzini <pbonzini@redhat.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: jmattson@google.com, wanpengli@tencent.com,
Junaid Shahid <junaids@google.com>
Subject: [PATCH 1/2] KVM: Fix NULL-ptr deref after kvm_create_vm fails
Date: Mon, 11 Nov 2019 14:25:40 +0100 [thread overview]
Message-ID: <1573478741-30959-2-git-send-email-pbonzini@redhat.com> (raw)
In-Reply-To: <1573478741-30959-1-git-send-email-pbonzini@redhat.com>
Reported by syzkaller:
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 14727 Comm: syz-executor.3 Not tainted 5.4.0-rc4+ #0
RIP: 0010:kvm_coalesced_mmio_init+0x5d/0x110 arch/x86/kvm/../../../virt/kvm/coalesced_mmio.c:121
Call Trace:
kvm_dev_ioctl_create_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:3446 [inline]
kvm_dev_ioctl+0x781/0x1490 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3494
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:509 [inline]
do_vfs_ioctl+0x196/0x1150 fs/ioctl.c:696
ksys_ioctl+0x62/0x90 fs/ioctl.c:713
__do_sys_ioctl fs/ioctl.c:720 [inline]
__se_sys_ioctl fs/ioctl.c:718 [inline]
__x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:718
do_syscall_64+0xca/0x5d0 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Commit 9121923c457d ("kvm: Allocate memslots and buses before calling kvm_arch_init_vm")
moves memslots and buses allocations around, however, if kvm->srcu/irq_srcu fails
initialization, NULL will be returned instead of error code, NULL will not be intercepted
in kvm_dev_ioctl_create_vm() and be deferenced by kvm_coalesced_mmio_init(), this patch
fixes it.
Moving the initialization is required anyway to avoid an incorrect synchronize_srcu that
was also reported by syzkaller:
wait_for_completion+0x29c/0x440 kernel/sched/completion.c:136
__synchronize_srcu+0x197/0x250 kernel/rcu/srcutree.c:921
synchronize_srcu_expedited kernel/rcu/srcutree.c:946 [inline]
synchronize_srcu+0x239/0x3e8 kernel/rcu/srcutree.c:997
kvm_page_track_unregister_notifier+0xe7/0x130 arch/x86/kvm/page_track.c:212
kvm_mmu_uninit_vm+0x1e/0x30 arch/x86/kvm/mmu.c:5828
kvm_arch_destroy_vm+0x4a2/0x5f0 arch/x86/kvm/x86.c:9579
kvm_create_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:702 [inline]
so do it.
Reported-by: syzbot+89a8060879fa0bd2db4f@syzkaller.appspotmail.com
Reported-by: syzbot+e27e7027eb2b80e44225@syzkaller.appspotmail.com
Fixes: 9121923c457d ("kvm: Allocate memslots and buses before calling kvm_arch_init_vm")
Cc: Jim Mattson <jmattson@google.com>
Cc: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
virt/kvm/kvm_main.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index d6f0696d98ef..e22ff63e5b1a 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -645,6 +645,11 @@ static struct kvm *kvm_create_vm(unsigned long type)
BUILD_BUG_ON(KVM_MEM_SLOTS_NUM > SHRT_MAX);
+ if (init_srcu_struct(&kvm->srcu))
+ goto out_err_no_srcu;
+ if (init_srcu_struct(&kvm->irq_srcu))
+ goto out_err_no_irq_srcu;
+
for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
struct kvm_memslots *slots = kvm_alloc_memslots();
@@ -675,11 +680,6 @@ static struct kvm *kvm_create_vm(unsigned long type)
INIT_HLIST_HEAD(&kvm->irq_ack_notifier_list);
#endif
- if (init_srcu_struct(&kvm->srcu))
- goto out_err_no_srcu;
- if (init_srcu_struct(&kvm->irq_srcu))
- goto out_err_no_irq_srcu;
-
r = kvm_init_mmu_notifier(kvm);
if (r)
goto out_err;
@@ -693,10 +693,6 @@ static struct kvm *kvm_create_vm(unsigned long type)
return kvm;
out_err:
- cleanup_srcu_struct(&kvm->irq_srcu);
-out_err_no_irq_srcu:
- cleanup_srcu_struct(&kvm->srcu);
-out_err_no_srcu:
hardware_disable_all();
out_err_no_disable:
kvm_arch_destroy_vm(kvm);
@@ -706,6 +702,10 @@ static struct kvm *kvm_create_vm(unsigned long type)
kfree(kvm_get_bus(kvm, i));
for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++)
kvm_free_memslots(kvm, __kvm_memslots(kvm, i));
+ cleanup_srcu_struct(&kvm->irq_srcu);
+out_err_no_irq_srcu:
+ cleanup_srcu_struct(&kvm->srcu);
+out_err_no_srcu:
kvm_arch_free_vm(kvm);
mmdrop(current->mm);
return ERR_PTR(r);
--
1.8.3.1
next prev parent reply other threads:[~2019-11-11 13:25 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-11 13:25 [PATCH 0/2] KVM: fix issues with kvm_create_vm failures Paolo Bonzini
2019-11-11 13:25 ` Paolo Bonzini [this message]
2019-11-12 18:49 ` [PATCH 1/2] KVM: Fix NULL-ptr deref after kvm_create_vm fails Jim Mattson
2019-11-11 13:25 ` [PATCH 2/2] KVM: fix placement of refcount initialization Paolo Bonzini
2019-11-12 18:50 ` Jim Mattson
2019-11-12 0:52 ` [PATCH 0/2] KVM: fix issues with kvm_create_vm failures Wanpeng Li
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1573478741-30959-2-git-send-email-pbonzini@redhat.com \
--to=pbonzini@redhat.com \
--cc=jmattson@google.com \
--cc=junaids@google.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=wanpengli@tencent.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).