| Message ID | 20230118195905.gonna.693-kees@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] KVM: x86: Replace 0-length arrays with flexible arrays | expand |
On Wed, 18 Jan 2023 11:59:09 -0800, Kees Cook wrote: > Zero-length arrays are deprecated[1]. Replace struct kvm_nested_state's > "data" union 0-length arrays with flexible arrays. (How are the > sizes of these arrays verified?) Detected with GCC 13, using > -fstrict-flex-arrays=3: > > arch/x86/kvm/svm/nested.c: In function 'svm_get_nested_state': > arch/x86/kvm/svm/nested.c:1536:17: error: array subscript 0 is outside array bounds of 'struct kvm_svm_nested_state_data[0]' [-Werror=array-bounds=] > 1536 | &user_kvm_nested_state->data.svm[0]; > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > In file included from include/uapi/linux/kvm.h:15, > from include/linux/kvm_host.h:40, > from arch/x86/kvm/svm/nested.c:18: > arch/x86/include/uapi/asm/kvm.h:511:50: note: while referencing 'svm' > 511 | struct kvm_svm_nested_state_data svm[0]; > | ^~~ > > [...] Applied to kvm-x86 misc, thanks! Based on the linux-next complaint, I assume you (temporarily?) applied this to your tree as well. Holler if I've confused you :-) [1/1] KVM: x86: Replace 0-length arrays with flexible arrays https://github.com/kvm-x86/linux/commit/2a8c2de0544e -- https://github.com/kvm-x86/linux/tree/next https://github.com/kvm-x86/linux/tree/fixes
On Thu, Jan 19, 2023 at 08:48:52PM +0000, Sean Christopherson wrote: > On Wed, 18 Jan 2023 11:59:09 -0800, Kees Cook wrote: > > Zero-length arrays are deprecated[1]. Replace struct kvm_nested_state's > > "data" union 0-length arrays with flexible arrays. (How are the > > sizes of these arrays verified?) Detected with GCC 13, using > > -fstrict-flex-arrays=3: > > > > arch/x86/kvm/svm/nested.c: In function 'svm_get_nested_state': > > arch/x86/kvm/svm/nested.c:1536:17: error: array subscript 0 is outside array bounds of 'struct kvm_svm_nested_state_data[0]' [-Werror=array-bounds=] > > 1536 | &user_kvm_nested_state->data.svm[0]; > > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > In file included from include/uapi/linux/kvm.h:15, > > from include/linux/kvm_host.h:40, > > from arch/x86/kvm/svm/nested.c:18: > > arch/x86/include/uapi/asm/kvm.h:511:50: note: while referencing 'svm' > > 511 | struct kvm_svm_nested_state_data svm[0]; > > | ^~~ > > > > [...] > > Applied to kvm-x86 misc, thanks! Based on the linux-next complaint, I assume > you (temporarily?) applied this to your tree as well. Holler if I've confused > you :-) Thanks! I've removed it from my tree.
diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h index e48deab8901d..bde47f3a8c9d 100644 --- a/arch/x86/include/uapi/asm/kvm.h +++ b/arch/x86/include/uapi/asm/kvm.h @@ -9,6 +9,7 @@ #include <linux/types.h> #include <linux/ioctl.h> +#include <linux/stddef.h> #define KVM_PIO_PAGE_OFFSET 1 #define KVM_COALESCED_MMIO_PAGE_OFFSET 2 @@ -507,8 +508,8 @@ struct kvm_nested_state { * KVM_{GET,PUT}_NESTED_STATE ioctl values. */ union { - struct kvm_vmx_nested_state_data vmx[0]; - struct kvm_svm_nested_state_data svm[0]; + __DECLARE_FLEX_ARRAY(struct kvm_vmx_nested_state_data, vmx); + __DECLARE_FLEX_ARRAY(struct kvm_svm_nested_state_data, svm); } data; };
Zero-length arrays are deprecated[1]. Replace struct kvm_nested_state's "data" union 0-length arrays with flexible arrays. (How are the sizes of these arrays verified?) Detected with GCC 13, using -fstrict-flex-arrays=3: arch/x86/kvm/svm/nested.c: In function 'svm_get_nested_state': arch/x86/kvm/svm/nested.c:1536:17: error: array subscript 0 is outside array bounds of 'struct kvm_svm_nested_state_data[0]' [-Werror=array-bounds=] 1536 | &user_kvm_nested_state->data.svm[0]; | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from include/uapi/linux/kvm.h:15, from include/linux/kvm_host.h:40, from arch/x86/kvm/svm/nested.c:18: arch/x86/include/uapi/asm/kvm.h:511:50: note: while referencing 'svm' 511 | struct kvm_svm_nested_state_data svm[0]; | ^~~ [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#zero-length-and-one-element-arrays Cc: Sean Christopherson <seanjc@google.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org> Cc: x86@kernel.org Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: kvm@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Sean Christopherson <seanjc@google.com> Link: https://lore.kernel.org/r/20230105190548.never.323-kees@kernel.org --- v2: add missing stddef.h include v1: https://lore.kernel.org/all/20230105190548.never.323-kees@kernel.org/ --- arch/x86/include/uapi/asm/kvm.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)