arch/x86/kvm/xen.c | 2 +- virt/kvm/pfncache.c | 3 +++ 2 files changed, 4 insertions(+), 1 deletion(-)
Check for invalid hva address stored in data and return -EINVAL before
calling into __kvm_gpc_activate().
Reported-by: syzbot+fd555292a1da3180fc82@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=fd555292a1da3180fc82
Tested-by: syzbot+fd555292a1da3180fc82@syzkaller.appspotmail.com
Signed-off-by: Pei Li <peili.dev@gmail.com>
---
Syzbot reports a warning message in __kvm_gpc_refresh(). This warning
requires at least one of gpa and uhva to be valid.
WARNING: CPU: 0 PID: 5090 at arch/x86/kvm/../../../virt/kvm/pfncache.c:259 __kvm_gpc_refresh+0xf17/0x1090 arch/x86/kvm/../../../virt/kvm/pfncache.c:259
We are calling it from kvm_gpc_activate_hva(). This function always calls
__kvm_gpc_activate() with INVALID_GPA. Thus, uhva must be valid to
disable this warning.
This patch checks for invalid hva address and return -EINVAL before
calling __kvm_gpc_activate().
syzbot has tested the proposed patch and the reproducer did not trigger
any issue.
Tested on:
commit: afcd4813 Merge tag 'mm-hotfixes-stable-2024-06-26-17-2..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1427e301980000
kernel config: https://syzkaller.appspot.com/x/.config?x=e40800950091403a
dashboard link: https://syzkaller.appspot.com/bug?extid=fd555292a1da3180fc82
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch: https://syzkaller.appspot.com/x/patch.diff?x=13838f3e980000
Note: testing is done by a robot and is best-effort only.
---
Changes in v2:
- Adapted Sean's suggestion to check for valid address before calling
into __kvm_gpc_activate().
- Link to v1: https://lore.kernel.org/r/20240625-bug5-v1-1-e072ed5fce85@gmail.com
---
arch/x86/kvm/xen.c | 2 +-
virt/kvm/pfncache.c | 3 +++
2 files changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c
index f65b35a05d91..67bb4e89c399 100644
--- a/arch/x86/kvm/xen.c
+++ b/arch/x86/kvm/xen.c
@@ -741,7 +741,7 @@ int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
} else {
void __user * hva = u64_to_user_ptr(data->u.shared_info.hva);
- if (!PAGE_ALIGNED(hva) || !access_ok(hva, PAGE_SIZE)) {
+ if (!PAGE_ALIGNED(hva)) {
r = -EINVAL;
} else if (!hva) {
kvm_gpc_deactivate(&kvm->arch.xen.shinfo_cache);
diff --git a/virt/kvm/pfncache.c b/virt/kvm/pfncache.c
index e3453e869e92..f0039efb9e1e 100644
--- a/virt/kvm/pfncache.c
+++ b/virt/kvm/pfncache.c
@@ -430,6 +430,9 @@ int kvm_gpc_activate(struct gfn_to_pfn_cache *gpc, gpa_t gpa, unsigned long len)
int kvm_gpc_activate_hva(struct gfn_to_pfn_cache *gpc, unsigned long uhva, unsigned long len)
{
+ if (!access_ok((void __user *)uhva, len))
+ return -EINVAL;
+
return __kvm_gpc_activate(gpc, INVALID_GPA, uhva, len);
}
---
base-commit: 2bfcfd584ff5ccc8bb7acde19b42570414bf880b
change-id: 20240625-bug5-5d332b5e5161
Best regards,
--
Pei Li <peili.dev@gmail.com>On Thu, 27 Jun 2024 08:03:56 -0700, Pei Li wrote:
> Check for invalid hva address stored in data and return -EINVAL before
> calling into __kvm_gpc_activate().
Applied to kvm-x86 fixes, thanks!
[1/1] kvm: Fix warning in__kvm_gpc_refresh
https://github.com/kvm-x86/linux/commit/ebbdf37ce9ab
--
https://github.com/kvm-x86/linux/tree/next
On 27/06/2024 16:03, Pei Li wrote: > Check for invalid hva address stored in data and return -EINVAL before > calling into __kvm_gpc_activate(). > > Reported-by: syzbot+fd555292a1da3180fc82@syzkaller.appspotmail.com > Closes: https://syzkaller.appspot.com/bug?extid=fd555292a1da3180fc82 > Tested-by: syzbot+fd555292a1da3180fc82@syzkaller.appspotmail.com > Signed-off-by: Pei Li <peili.dev@gmail.com> > --- > Syzbot reports a warning message in __kvm_gpc_refresh(). This warning > requires at least one of gpa and uhva to be valid. > WARNING: CPU: 0 PID: 5090 at arch/x86/kvm/../../../virt/kvm/pfncache.c:259 __kvm_gpc_refresh+0xf17/0x1090 arch/x86/kvm/../../../virt/kvm/pfncache.c:259 > > We are calling it from kvm_gpc_activate_hva(). This function always calls > __kvm_gpc_activate() with INVALID_GPA. Thus, uhva must be valid to > disable this warning. > > This patch checks for invalid hva address and return -EINVAL before > calling __kvm_gpc_activate(). > > syzbot has tested the proposed patch and the reproducer did not trigger > any issue. > > Tested on: > > commit: afcd4813 Merge tag 'mm-hotfixes-stable-2024-06-26-17-2.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=1427e301980000 > kernel config: https://syzkaller.appspot.com/x/.config?x=e40800950091403a > dashboard link: https://syzkaller.appspot.com/bug?extid=fd555292a1da3180fc82 > compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 > patch: https://syzkaller.appspot.com/x/patch.diff?x=13838f3e980000 > > Note: testing is done by a robot and is best-effort only. > --- > Changes in v2: > - Adapted Sean's suggestion to check for valid address before calling > into __kvm_gpc_activate(). > - Link to v1: https://lore.kernel.org/r/20240625-bug5-v1-1-e072ed5fce85@gmail.com > --- > arch/x86/kvm/xen.c | 2 +- > virt/kvm/pfncache.c | 3 +++ > 2 files changed, 4 insertions(+), 1 deletion(-) > Reviewed-by: Paul Durrant <paul@xen.org>
On Fri, 2024-06-28 at 15:25 +0100, Paul Durrant wrote: > On 27/06/2024 16:03, Pei Li wrote: > > Check for invalid hva address stored in data and return -EINVAL before > > calling into __kvm_gpc_activate(). > > > > Reported-by: syzbot+fd555292a1da3180fc82@syzkaller.appspotmail.com > > Closes: https://syzkaller.appspot.com/bug?extid=fd555292a1da3180fc82 > > Tested-by: syzbot+fd555292a1da3180fc82@syzkaller.appspotmail.com > > Signed-off-by: Pei Li <peili.dev@gmail.com> > > --- > > Syzbot reports a warning message in __kvm_gpc_refresh(). This warning > > requires at least one of gpa and uhva to be valid. > > WARNING: CPU: 0 PID: 5090 at arch/x86/kvm/../../../virt/kvm/pfncache.c:259 __kvm_gpc_refresh+0xf17/0x1090 arch/x86/kvm/../../../virt/kvm/pfncache.c:259 > > > > We are calling it from kvm_gpc_activate_hva(). This function always calls > > __kvm_gpc_activate() with INVALID_GPA. Thus, uhva must be valid to > > disable this warning. > > > > This patch checks for invalid hva address and return -EINVAL before > > calling __kvm_gpc_activate(). > > > > syzbot has tested the proposed patch and the reproducer did not trigger > > any issue. > > > > Tested on: > > > > commit: afcd4813 Merge tag 'mm-hotfixes-stable-2024-06-26-17-2.. > > git tree: upstream > > console output: https://syzkaller.appspot.com/x/log.txt?x=1427e301980000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=e40800950091403a > > dashboard link: https://syzkaller.appspot.com/bug?extid=fd555292a1da3180fc82 > > compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 > > patch: https://syzkaller.appspot.com/x/patch.diff?x=13838f3e980000 > > > > Note: testing is done by a robot and is best-effort only. > > --- > > Changes in v2: > > - Adapted Sean's suggestion to check for valid address before calling > > into __kvm_gpc_activate(). > > - Link to v1: https://lore.kernel.org/r/20240625-bug5-v1-1-e072ed5fce85@gmail.com > > --- > > arch/x86/kvm/xen.c | 2 +- > > virt/kvm/pfncache.c | 3 +++ > > 2 files changed, 4 insertions(+), 1 deletion(-) > > > > Reviewed-by: Paul Durrant <paul@xen.org> Reviewed-by: David Woodhouse <dwmw@amazon.co.uk> Thanks.
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