An integer overflow is possible in dev_map_bitmap_size() when
calculating the BITS_TO_LONG logic which becomes, after macro
replacement,
(((n) + (d) - 1)/ (d))
where 'n' is a __u32 and 'd' is (8 * sizeof(long)). To avoid
overflow cast to u64 before arithmetic.
Reported-by: Richard Weinberger <[email protected]>
Acked-by: Daniel Borkmann <[email protected]>
Signed-off-by: John Fastabend <[email protected]>
---
kernel/bpf/devmap.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index 7d9f32f..6d3ec97 100644
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -69,7 +69,7 @@ static LIST_HEAD(dev_map_list);
static u64 dev_map_bitmap_size(const union bpf_attr *attr)
{
- return BITS_TO_LONGS(attr->max_entries) * sizeof(unsigned long);
+ return BITS_TO_LONGS((u64) attr->max_entries) * sizeof(unsigned long);
}
static struct bpf_map *dev_map_alloc(union bpf_attr *attr)
