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Diffstat (limited to 'kernel/bpf/ringbuf.c')
-rw-r--r--kernel/bpf/ringbuf.c24
1 files changed, 11 insertions, 13 deletions
diff --git a/kernel/bpf/ringbuf.c b/kernel/bpf/ringbuf.c
index f25b719ac786..84b3b35fc0d0 100644
--- a/kernel/bpf/ringbuf.c
+++ b/kernel/bpf/ringbuf.c
@@ -221,25 +221,20 @@ static int ringbuf_map_get_next_key(struct bpf_map *map, void *key,
return -ENOTSUPP;
}
-static size_t bpf_ringbuf_mmap_page_cnt(const struct bpf_ringbuf *rb)
-{
- size_t data_pages = (rb->mask + 1) >> PAGE_SHIFT;
-
- /* consumer page + producer page + 2 x data pages */
- return RINGBUF_POS_PAGES + 2 * data_pages;
-}
-
static int ringbuf_map_mmap(struct bpf_map *map, struct vm_area_struct *vma)
{
struct bpf_ringbuf_map *rb_map;
- size_t mmap_sz;
rb_map = container_of(map, struct bpf_ringbuf_map, map);
- mmap_sz = bpf_ringbuf_mmap_page_cnt(rb_map->rb) << PAGE_SHIFT;
-
- if (vma->vm_pgoff * PAGE_SIZE + (vma->vm_end - vma->vm_start) > mmap_sz)
- return -EINVAL;
+ if (vma->vm_flags & VM_WRITE) {
+ /* allow writable mapping for the consumer_pos only */
+ if (vma->vm_pgoff != 0 || vma->vm_end - vma->vm_start != PAGE_SIZE)
+ return -EPERM;
+ } else {
+ vma->vm_flags &= ~VM_MAYWRITE;
+ }
+ /* remap_vmalloc_range() checks size and offset constraints */
return remap_vmalloc_range(vma, rb_map->rb,
vma->vm_pgoff + RINGBUF_PGOFF);
}
@@ -315,6 +310,9 @@ static void *__bpf_ringbuf_reserve(struct bpf_ringbuf *rb, u64 size)
return NULL;
len = round_up(size + BPF_RINGBUF_HDR_SZ, 8);
+ if (len > rb->mask + 1)
+ return NULL;
+
cons_pos = smp_load_acquire(&rb->consumer_pos);
if (in_nmi()) {