Messages in this thread | | | Date | Thu, 31 Aug 2023 14:11:32 -0700 | From | Kees Cook <> | Subject | Re: [PATCH] x86/audit: fix -Wmissing-variable-declarations warning for ia32_xyz_class |
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On Tue, Aug 29, 2023 at 10:33:16PM +0000, Justin Stitt wrote: > When building x86 defconfig with Clang-18 I get the following warnings: > | arch/x86/ia32/audit.c:6:10: warning: no previous extern declaration for non-static variable 'ia32_dir_class' [-Wmissing-variable-declarations] > | 6 | unsigned ia32_dir_class[] = { > | arch/x86/ia32/audit.c:11:10: warning: no previous extern declaration for non-static variable 'ia32_chattr_class' [-Wmissing-variable-declarations] > | 11 | unsigned ia32_chattr_class[] = { > | arch/x86/ia32/audit.c:16:10: warning: no previous extern declaration for non-static variable 'ia32_write_class' [-Wmissing-variable-declarations] > | 16 | unsigned ia32_write_class[] = { > | arch/x86/ia32/audit.c:21:10: warning: no previous extern declaration for non-static variable 'ia32_read_class' [-Wmissing-variable-declarations] > | 21 | unsigned ia32_read_class[] = { > | arch/x86/ia32/audit.c:26:10: warning: no previous extern declaration for non-static variable 'ia32_signal_class' [-Wmissing-variable-declarations] > | 26 | unsigned ia32_signal_class[] = { > > These warnings occur due to their respective extern declarations being > scoped inside of audit_classes_init as well as only being enabled with > `CONFIG_IA32_EMULATION=y`: > | static int __init audit_classes_init(void) > | { > | #ifdef CONFIG_IA32_EMULATION > | extern __u32 ia32_dir_class[]; > | extern __u32 ia32_write_class[]; > | extern __u32 ia32_read_class[]; > | extern __u32 ia32_chattr_class[]; > | audit_register_class(AUDIT_CLASS_WRITE_32, ia32_write_class); > | audit_register_class(AUDIT_CLASS_READ_32, ia32_read_class); > | audit_register_class(AUDIT_CLASS_DIR_WRITE_32, ia32_dir_class); > | audit_register_class(AUDIT_CLASS_CHATTR_32, ia32_chattr_class); > | #endif > | audit_register_class(AUDIT_CLASS_WRITE, write_class); > | audit_register_class(AUDIT_CLASS_READ, read_class); > | audit_register_class(AUDIT_CLASS_DIR_WRITE, dir_class); > | audit_register_class(AUDIT_CLASS_CHATTR, chattr_class); > | return 0; > | } > > Lift the extern declarations to their own header and resolve scoping > issues (and thus fix the warnings). > > Moreover, change __u32 to unsigned so that we match the definitions: > | unsigned ia32_dir_class[] = { > | #include <asm-generic/audit_dir_write.h> > | ~0U > | }; > | > | unsigned ia32_chattr_class[] = { > | #include <asm-generic/audit_change_attr.h> > | ~0U > | }; > | ...
I would expect checkpatch to warn about bare "unsigned", which is frown on these days. :) I think __u32 should be fine here...? (Why is it __u32 instead of u32, btw?)
But otherwise, yes, looks good.
-Kees
-- Kees Cook
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