2020-09-18 12:09:05

by Rustam Kovhaev

[permalink] [raw]
Subject: [PATCH] KVM: use struct_size() and flex_array_size() helpers in kvm_io_bus_unregister_dev()

Make use of the struct_size() helper to avoid any potential type
mistakes and protect against potential integer overflows
Make use of the flex_array_size() helper to calculate the size of a
flexible array member within an enclosing structure

Cc: [email protected]
Suggested-by: Gustavo A. R. Silva <[email protected]>
Signed-off-by: Rustam Kovhaev <[email protected]>
---
virt/kvm/kvm_main.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index cf88233b819a..68edd25dcb11 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -4350,10 +4350,10 @@ void kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx,
new_bus = kmalloc(struct_size(bus, range, bus->dev_count - 1),
GFP_KERNEL_ACCOUNT);
if (new_bus) {
- memcpy(new_bus, bus, sizeof(*bus) + i * sizeof(struct kvm_io_range));
+ memcpy(new_bus, bus, struct_size(bus, range, i));
new_bus->dev_count--;
memcpy(new_bus->range + i, bus->range + i + 1,
- (new_bus->dev_count - i) * sizeof(struct kvm_io_range));
+ flex_array_size(new_bus, range, new_bus->dev_count - i));
} else {
pr_err("kvm: failed to shrink bus, removing it completely\n");
for (j = 0; j < bus->dev_count; j++) {
--
2.28.0


2020-09-19 00:06:13

by Gustavo A. R. Silva

[permalink] [raw]
Subject: Re: [PATCH] KVM: use struct_size() and flex_array_size() helpers in kvm_io_bus_unregister_dev()

On Fri, Sep 18, 2020 at 05:05:00AM -0700, Rustam Kovhaev wrote:
> Make use of the struct_size() helper to avoid any potential type
> mistakes and protect against potential integer overflows
> Make use of the flex_array_size() helper to calculate the size of a
> flexible array member within an enclosing structure
>
> Cc: [email protected]

I don't think this change applies for -stable.

> Suggested-by: Gustavo A. R. Silva <[email protected]>
> Signed-off-by: Rustam Kovhaev <[email protected]>

Reviewed-by: Gustavo A. R. Silva <[email protected]>

Thanks!
--
Gustavo

> ---
> virt/kvm/kvm_main.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index cf88233b819a..68edd25dcb11 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -4350,10 +4350,10 @@ void kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx,
> new_bus = kmalloc(struct_size(bus, range, bus->dev_count - 1),
> GFP_KERNEL_ACCOUNT);
> if (new_bus) {
> - memcpy(new_bus, bus, sizeof(*bus) + i * sizeof(struct kvm_io_range));
> + memcpy(new_bus, bus, struct_size(bus, range, i));
> new_bus->dev_count--;
> memcpy(new_bus->range + i, bus->range + i + 1,
> - (new_bus->dev_count - i) * sizeof(struct kvm_io_range));
> + flex_array_size(new_bus, range, new_bus->dev_count - i));
> } else {
> pr_err("kvm: failed to shrink bus, removing it completely\n");
> for (j = 0; j < bus->dev_count; j++) {
> --
> 2.28.0
>

2020-09-21 12:57:11

by Sasha Levin

[permalink] [raw]
Subject: Re: [PATCH] KVM: use struct_size() and flex_array_size() helpers in kvm_io_bus_unregister_dev()

Hi

[This is an automated email]

This commit has been processed because it contains a -stable tag.
The stable tag indicates that it's relevant for the following trees: all

The bot has tested the following trees: v5.8.10, v5.4.66, v4.19.146, v4.14.198, v4.9.236, v4.4.236.

v5.8.10: Build OK!
v5.4.66: Build failed! Errors:
virt/kvm/kvm_main.c:4034:5: error: implicit declaration of function ‘flex_array_size’; did you mean ‘array_size’? [-Werror=implicit-function-declaration]
virt/kvm/kvm_main.c:4034:30: error: ‘range’ undeclared (first use in this function)
virt/kvm/kvm_main.c:4034:5: error: implicit declaration of function ‘flex_array_size’; did you mean ‘array_size’? [-Werror=implicit-function-declaration]
virt/kvm/kvm_main.c:4034:30: error: ‘range’ undeclared (first use in this function)
arch/s390/kvm/../../../virt/kvm/kvm_main.c:4034:5: error: implicit declaration of function 'flex_array_size'; did you mean 'array_size'? [-Werror=implicit-function-declaration]
arch/s390/kvm/../../../virt/kvm/kvm_main.c:4034:30: error: 'range' undeclared (first use in this function)
virt/kvm/kvm_main.c:4034:5: error: implicit declaration of function ‘flex_array_size’; did you mean ‘array_size’? [-Werror=implicit-function-declaration]
virt/kvm/kvm_main.c:4034:30: error: ‘range’ undeclared (first use in this function)
virt/kvm/kvm_main.c:4034:5: error: implicit declaration of function ‘flex_array_size’; did you mean ‘array_size’? [-Werror=implicit-function-declaration]
virt/kvm/kvm_main.c:4034:30: error: ‘range’ undeclared (first use in this function)
arch/s390/kvm/../../../virt/kvm/kvm_main.c:4034:5: error: implicit declaration of function 'flex_array_size'; did you mean 'array_size'? [-Werror=implicit-function-declaration]
arch/s390/kvm/../../../virt/kvm/kvm_main.c:4034:30: error: 'range' undeclared (first use in this function)
virt/kvm/kvm_main.c:4034:5: error: implicit declaration of function ‘flex_array_size’; did you mean ‘array_size’? [-Werror=implicit-function-declaration]
virt/kvm/kvm_main.c:4034:30: error: ‘range’ undeclared (first use in this function)
virt/kvm/kvm_main.c:4034:5: error: implicit declaration of function ‘flex_array_size’; did you mean ‘array_size’? [-Werror=implicit-function-declaration]
virt/kvm/kvm_main.c:4034:30: error: ‘range’ undeclared (first use in this function)
arch/s390/kvm/../../../virt/kvm/kvm_main.c:4034:5: error: implicit declaration of function 'flex_array_size'; did you mean 'array_size'? [-Werror=implicit-function-declaration]
arch/s390/kvm/../../../virt/kvm/kvm_main.c:4034:30: error: 'range' undeclared (first use in this function)
virt/kvm/kvm_main.c:4034:5: error: implicit declaration of function ‘flex_array_size’; did you mean ‘array_size’? [-Werror=implicit-function-declaration]
virt/kvm/kvm_main.c:4034:30: error: ‘range’ undeclared (first use in this function)
virt/kvm/kvm_main.c:4034:5: error: implicit declaration of function ‘flex_array_size’; did you mean ‘array_size’? [-Werror=implicit-function-declaration]
virt/kvm/kvm_main.c:4034:30: error: ‘range’ undeclared (first use in this function)
arch/s390/kvm/../../../virt/kvm/kvm_main.c:4034:5: error: implicit declaration of function 'flex_array_size'; did you mean 'array_size'? [-Werror=implicit-function-declaration]
arch/s390/kvm/../../../virt/kvm/kvm_main.c:4034:30: error: 'range' undeclared (first use in this function)
arch/arm64/kvm/../../../virt/kvm/kvm_main.c:4034:5: error: implicit declaration of function 'flex_array_size'; did you mean 'array_size'? [-Werror=implicit-function-declaration]
arch/arm64/kvm/../../../virt/kvm/kvm_main.c:4034:30: error: 'range' undeclared (first use in this function)

v4.19.146: Failed to apply! Possible dependencies:
0804c849f1df ("kvm/x86 : add coalesced pio support")
360cae313702 ("KVM: PPC: Book3S HV: Nested guest entry via hypercall")
41f4e631daf8 ("KVM: PPC: Book3S HV: Extract PMU save/restore operations as C-callable functions")
89329c0be8bd ("KVM: PPC: Book3S HV: Clear partition table entry on vm teardown")
8e3f5fc1045d ("KVM: PPC: Book3S HV: Framework and hcall stubs for nested virtualization")
90952cd38859 ("kvm: Use struct_size() in kmalloc()")
95a6432ce903 ("KVM: PPC: Book3S HV: Streamlined guest entry/exit path on P9 for radix guests")
9943450b7b88 ("kvm/x86 : add document for coalesced mmio")
aa069a996951 ("KVM: PPC: Book3S HV: Add a VM capability to enable nested virtualization")
b12ce36a43f2 ("kvm: Add memcg accounting to KVM allocations")
df709a296ef7 ("KVM: PPC: Book3S HV: Simplify real-mode interrupt handling")
f7035ce9f1df ("KVM: PPC: Book3S HV: Move interrupt delivery on guest entry to C code")

v4.14.198: Failed to apply! Possible dependencies:
0804c849f1df ("kvm/x86 : add coalesced pio support")
7bf14c28ee77 ("Merge branch 'x86/hyperv' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip")
90952cd38859 ("kvm: Use struct_size() in kmalloc()")
b12ce36a43f2 ("kvm: Add memcg accounting to KVM allocations")
d4c67a7a54f1 ("kvm: use insert sort in kvm_io_bus_register_dev function")

v4.9.236: Failed to apply! Possible dependencies:
0804c849f1df ("kvm/x86 : add coalesced pio support")
4a12f9517728 ("KVM: mark kvm->busses as rcu protected")
7bf14c28ee77 ("Merge branch 'x86/hyperv' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip")
90952cd38859 ("kvm: Use struct_size() in kmalloc()")
b12ce36a43f2 ("kvm: Add memcg accounting to KVM allocations")
d4c67a7a54f1 ("kvm: use insert sort in kvm_io_bus_register_dev function")

v4.4.236: Failed to apply! Possible dependencies:
4a12f9517728 ("KVM: mark kvm->busses as rcu protected")
5c919412fe61 ("kvm/x86: Hyper-V synthetic interrupt controller")
6308630bd3db ("kvm/x86: split ioapic-handled and EOI exit bitmaps")
765eaa0f70ea ("kvm/x86: Hyper-V SynIC message slot pending clearing at SINT ack")
90952cd38859 ("kvm: Use struct_size() in kmalloc()")
d4c67a7a54f1 ("kvm: use insert sort in kvm_io_bus_register_dev function")
d62caabb41f3 ("kvm/x86: per-vcpu apicv deactivation support")


NOTE: The patch will not be queued to stable trees until it is upstream.

How should we proceed with this patch?

--
Thanks
Sasha

2020-09-22 12:44:44

by Paolo Bonzini

[permalink] [raw]
Subject: Re: [PATCH] KVM: use struct_size() and flex_array_size() helpers in kvm_io_bus_unregister_dev()

On 19/09/20 02:09, Gustavo A. R. Silva wrote:
> Reviewed-by: Gustavo A. R. Silva <[email protected]>

Queued, without stable. Thanks.

Paolo

2020-09-30 18:17:56

by Gustavo A. R. Silva

[permalink] [raw]
Subject: Re: [PATCH] KVM: use struct_size() and flex_array_size() helpers in kvm_io_bus_unregister_dev()

Hi Sasha,

On 9/21/20 07:54, Sasha Levin wrote:

>
> NOTE: The patch will not be queued to stable trees until it is upstream.
>
> How should we proceed with this patch?
>

This patch should not go to -stable.

The author has resent it without the _stable_ stag.

Thanks
--
Gustavo