diff options
| author | Jann Horn <jannh@google.com> | 2022-11-30 12:53:20 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2022-12-01 11:35:40 +0100 |
| commit | d6c494e8ee932b2b21ff4b718eebb378e91b3da0 (patch) | |
| tree | 90dc53f17eb09172eda357d3c7fc5527b599d811 /kernel/time | |
| parent | e0d3da982c96aeddc1bbf1cf9469dbb9ebdca657 (diff) | |
| download | linux-d6c494e8ee932b2b21ff4b718eebb378e91b3da0.tar.bz2 | |
vdso/timens: Refactor copy-pasted find_timens_vvar_page() helper into one copy
find_timens_vvar_page() is not architecture-specific, as can be seen from
how all five per-architecture versions of it are the same.
(arm64, powerpc and riscv are exactly the same; x86 and s390 have two
characters difference inside a comment, less blank lines, and mark the
!CONFIG_TIME_NS version as inline.)
Refactor the five copies into a central copy in kernel/time/namespace.c.
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20221130115320.2918447-1-jannh@google.com
Diffstat (limited to 'kernel/time')
| -rw-r--r-- | kernel/time/namespace.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/kernel/time/namespace.c b/kernel/time/namespace.c index aec832801c26..0775b9ec952a 100644 --- a/kernel/time/namespace.c +++ b/kernel/time/namespace.c @@ -192,6 +192,24 @@ static void timens_setup_vdso_data(struct vdso_data *vdata, offset[CLOCK_BOOTTIME_ALARM] = boottime; } +struct page *find_timens_vvar_page(struct vm_area_struct *vma) +{ + if (likely(vma->vm_mm == current->mm)) + return current->nsproxy->time_ns->vvar_page; + + /* + * VM_PFNMAP | VM_IO protect .fault() handler from being called + * through interfaces like /proc/$pid/mem or + * process_vm_{readv,writev}() as long as there's no .access() + * in special_mapping_vmops(). + * For more details check_vma_flags() and __access_remote_vm() + */ + + WARN(1, "vvar_page accessed remotely"); + + return NULL; +} + /* * Protects possibly multiple offsets writers racing each other * and tasks entering the namespace. |