On Wed, Mar 05, 2025 at 02:17:05AM +0000, jef...@chromium.org wrote: > From: Jeff Xu <jef...@chromium.org> > > Provide infrastructure to mseal system mappings. Establish > two kernel configs (CONFIG_MSEAL_SYSTEM_MAPPINGS, > ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS) and VM_SEALED_SYSMAP > macro for future patches. > > Signed-off-by: Jeff Xu <jef...@chromium.org> > Reviewed-by: Kees Cook <k...@kernel.org>
Umm... I reviewed this too? :) unless you made substantial changes here (doesn't appear so), please do propagate tags for each revision :>) Anyway, FWIW: Reviewed-by: Lorenzo Stoakes <lorenzo.stoa...@oracle.com> > --- > include/linux/mm.h | 10 ++++++++++ > init/Kconfig | 22 ++++++++++++++++++++++ > security/Kconfig | 21 +++++++++++++++++++++ > 3 files changed, 53 insertions(+) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 7b1068ddcbb7..8b800941678d 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -4155,4 +4155,14 @@ int arch_get_shadow_stack_status(struct task_struct > *t, unsigned long __user *st > int arch_set_shadow_stack_status(struct task_struct *t, unsigned long > status); > int arch_lock_shadow_stack_status(struct task_struct *t, unsigned long > status); > > + > +/* > + * mseal of userspace process's system mappings. > + */ > +#ifdef CONFIG_MSEAL_SYSTEM_MAPPINGS > +#define VM_SEALED_SYSMAP VM_SEALED > +#else > +#define VM_SEALED_SYSMAP VM_NONE > +#endif > + > #endif /* _LINUX_MM_H */ > diff --git a/init/Kconfig b/init/Kconfig > index d0d021b3fa3b..7f67d8942a09 100644 > --- a/init/Kconfig > +++ b/init/Kconfig > @@ -1882,6 +1882,28 @@ config ARCH_HAS_MEMBARRIER_CALLBACKS > config ARCH_HAS_MEMBARRIER_SYNC_CORE > bool > > +config ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS > + bool > + help > + Control MSEAL_SYSTEM_MAPPINGS access based on architecture. > + > + A 64-bit kernel is required for the memory sealing feature. > + No specific hardware features from the CPU are needed. > + > + To enable this feature, the architecture needs to update their > + special mappings calls to include the sealing flag and confirm > + that it doesn't unmap/remap system mappings during the life > + time of the process. The existence of this flag for an architecture > + implies that it does not require the remapping of the system > + mappings during process lifetime, so sealing these mappings is safe > + from a kernel perspective. > + > + After the architecture enables this, a distribution can set > + CONFIG_MSEAL_SYSTEM_MAPPING to manage access to the feature. > + > + For complete descriptions of memory sealing, please see > + Documentation/userspace-api/mseal.rst > + > config HAVE_PERF_EVENTS > bool > help > diff --git a/security/Kconfig b/security/Kconfig > index f10dbf15c294..a914a02df27e 100644 > --- a/security/Kconfig > +++ b/security/Kconfig > @@ -51,6 +51,27 @@ config PROC_MEM_NO_FORCE > > endchoice > > +config MSEAL_SYSTEM_MAPPINGS > + bool "mseal system mappings" > + depends on 64BIT > + depends on ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS > + depends on !CHECKPOINT_RESTORE > + help > + Apply mseal on system mappings. > + The system mappings includes vdso, vvar, vvar_vclock, > + vectors (arm compat-mode), sigpage (arm compat-mode), uprobes. > + > + A 64-bit kernel is required for the memory sealing feature. > + No specific hardware features from the CPU are needed. > + > + WARNING: This feature breaks programs which rely on relocating > + or unmapping system mappings. Known broken software at the time > + of writing includes CHECKPOINT_RESTORE, UML, gVisor, rr. Therefore > + this config can't be enabled universally. > + > + For complete descriptions of memory sealing, please see > + Documentation/userspace-api/mseal.rst > + > config SECURITY > bool "Enable different security models" > depends on SYSFS > -- > 2.48.1.711.g2feabab25a-goog >
