[PATCH v6 5/7] mseal, system mappings: enable uml architecture

jeffxu
2025-02-24T17:45:29Z

From: Jeff Xu <jeffxu@chromium.org>

Provide support for CONFIG_MSEAL_SYSTEM_MAPPINGS on UML, covering
the vdso.

Testing passes on UML.

Signed-off-by: Jeff Xu <jeffxu@chromium.org>
Tested-by: Benjamin Berg <benjamin.berg@intel.com>
---
arch/um/Kconfig | 1 +
arch/x86/um/vdso/vma.c | 6 ++++--
2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/um/Kconfig b/arch/um/Kconfig
index 18051b1cfce0..eb2d439a5334 100644
--- a/arch/um/Kconfig
+++ b/arch/um/Kconfig
@@ -10,6 +10,7 @@ config UML
select ARCH_HAS_FORTIFY_SOURCE
select ARCH_HAS_GCOV_PROFILE_ALL
select ARCH_HAS_KCOV
+ select ARCH_HAS_MSEAL_SYSTEM_MAPPINGS
select ARCH_HAS_STRNCPY_FROM_USER
select ARCH_HAS_STRNLEN_USER
select HAVE_ARCH_AUDITSYSCALL
diff --git a/arch/x86/um/vdso/vma.c b/arch/x86/um/vdso/vma.c
index f238f7b33cdd..ee6d8a58f9f6 100644
--- a/arch/x86/um/vdso/vma.c
+++ b/arch/x86/um/vdso/vma.c
@@ -54,6 +54,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
{
struct vm_area_struct *vma;
struct mm_struct *mm = current->mm;
+ unsigned long vm_flags;
static struct vm_special_mapping vdso_mapping = {
.name = "[vdso]",
};
@@ -65,9 +66,10 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
return -EINTR;

vdso_mapping.pages = vdsop;
+ vm_flags = VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC;
+ vm_flags |= MSEAL_SYSTEM_MAPPINGS_VM_FLAG;
vma = _install_special_mapping(mm, um_vdso_addr, PAGE_SIZE,
- VM_READ|VM_EXEC|
- VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
+ vm_flags,
&vdso_mapping);

mmap_write_unlock(mm);
--
2.48.1.601.g30ceb7b040-goog