diff options
Diffstat (limited to 'mm/shmem.c')
| -rw-r--r-- | mm/shmem.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/mm/shmem.c b/mm/shmem.c index f4dce9c8670d..b093b429d325 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2196,11 +2196,14 @@ static int shmem_mmap(struct file *file, struct vm_area_struct *vma) return -EPERM; /* - * Since the F_SEAL_FUTURE_WRITE seals allow for a MAP_SHARED - * read-only mapping, take care to not allow mprotect to revert - * protections. + * Since an F_SEAL_FUTURE_WRITE sealed memfd can be mapped as + * MAP_SHARED and read-only, take care to not allow mprotect to + * revert protections on such mappings. Do this only for shared + * mappings. For private mappings, don't need to mask + * VM_MAYWRITE as we still want them to be COW-writable. */ - vma->vm_flags &= ~(VM_MAYWRITE); + if (vma->vm_flags & VM_SHARED) + vma->vm_flags &= ~(VM_MAYWRITE); } file_accessed(file); |