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| author | John Fastabend <john.r.fastabend@gmail.com> | 2017-10-19 19:03:52 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-10-22 02:54:09 +0300 |
| commit | 8695a5395661fbb4a4f26c97f801f3800ae4754e (patch) | |
| tree | d7f30a46a501e695325675205354a69c29bad81e | |
| parent | 43ebf97fa40fc49242110d2bd50334fc6e95c802 (diff) | |
| download | linux-8695a5395661fbb4a4f26c97f801f3800ae4754e.tar.xz | |
bpf: devmap fix arithmetic overflow in bitmap_size calculation
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 <richard@nod.at>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | kernel/bpf/devmap.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c index 52e0548ba548..e745d6a88224 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) |