On 2/24/25 09:45, jef...@chromium.org wrote:
> +/*
> + * mseal of userspace process's system mappings.
> + */
> +#ifdef CONFIG_MSEAL_SYSTEM_MAPPINGS
> +#define MSEAL_SYSTEM_MAPPINGS_VM_FLAG VM_SEALED
> +#else
> +#define MSEAL_SYSTEM_MAPPINGS_VM_FLAG VM_NONE
> +#endif
This ends up looking pretty wonky in practice:
> + vm_flags = VM_READ|VM_MAYREAD|VM_IO|VM_DONTDUMP|VM_PFNMAP;
> + vm_flags |= MSEAL_SYSTEM_MAPPINGS_VM_FLAG;
because MSEAL_SYSTEM_MAPPINGS_VM_FLAG is so much different from the
other ones.
Would it really hurt to have
#ifdef CONFIG_64BIT
/* VM is sealed, in vm_flags */
#define VM_SEALED _BITUL(63)
+#else
+#define VM_SEALED VM_NONE
#endif
?
Then all the users could just do:
vm_flags = VM_READ|VM_MAYREAD|VM_IO|VM_DONTDUMP|VM_PFNMAP|
VM_SEALED
That seems to be a the common way of doing things. Take a look at:
# define VM_GROWSUP VM_NONE
...
# define VM_MTE VM_NONE
# define VM_MTE_ALLOWED VM_NONE
...
# define VM_UFFD_MINOR VM_NONE
...
#define VM_DROPPABLE VM_NONE
... and more
