diff options
| -rw-r--r-- | kernel/bpf/syscall.c | 16 |
1 files changed, 7 insertions, 9 deletions
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 64783da34202..d85f37239540 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -586,9 +586,7 @@ static void bpf_map_mmap_open(struct vm_area_struct *vma) { struct bpf_map *map = vma->vm_file->private_data; - bpf_map_inc_with_uref(map); - - if (vma->vm_flags & VM_WRITE) { + if (vma->vm_flags & VM_MAYWRITE) { mutex_lock(&map->freeze_mutex); map->writecnt++; mutex_unlock(&map->freeze_mutex); @@ -600,13 +598,11 @@ static void bpf_map_mmap_close(struct vm_area_struct *vma) { struct bpf_map *map = vma->vm_file->private_data; - if (vma->vm_flags & VM_WRITE) { + if (vma->vm_flags & VM_MAYWRITE) { mutex_lock(&map->freeze_mutex); map->writecnt--; mutex_unlock(&map->freeze_mutex); } - - bpf_map_put_with_uref(map); } static const struct vm_operations_struct bpf_map_default_vmops = { @@ -635,14 +631,16 @@ static int bpf_map_mmap(struct file *filp, struct vm_area_struct *vma) /* set default open/close callbacks */ vma->vm_ops = &bpf_map_default_vmops; vma->vm_private_data = map; + vma->vm_flags &= ~VM_MAYEXEC; + if (!(vma->vm_flags & VM_WRITE)) + /* disallow re-mapping with PROT_WRITE */ + vma->vm_flags &= ~VM_MAYWRITE; err = map->ops->map_mmap(map, vma); if (err) goto out; - bpf_map_inc_with_uref(map); - - if (vma->vm_flags & VM_WRITE) + if (vma->vm_flags & VM_MAYWRITE) map->writecnt++; out: mutex_unlock(&map->freeze_mutex); |