Hi Maya,
On Thu, Feb 18, 2021 at 01:06:38PM +0200, Maya Rashish wrote:
> When data is smaller than the destination, &ctr->pkts.
>
> This might introduce some issues since we're now not
> filling the rest of the memory, but filling out with
> uninitialized garbage is probably as bad as leaving it
> as garbage.
Probably you could update src/expr/ to use nftnl_assert_validate() to
sanity check the input data length?
Please, have a look at nftnl_assert_attr_exists() and
nftnl_assert_validate().
> Signed-off-by: Maya Rashish <mrashish@xxxxxxxxxx>
> ---
> include/utils.h | 2 ++
> src/expr/counter.c | 4 ++--
> 2 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/include/utils.h b/include/utils.h
> index 8af5a8e..6b22e46 100644
> --- a/include/utils.h
> +++ b/include/utils.h
> @@ -67,6 +67,8 @@ void __nftnl_assert_attr_exists(uint16_t attr, uint16_t attr_max,
>
> #define array_size(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
>
> +#define MIN(a,b) ((a) > (b) ? (b) : (a))
> +
> const char *nftnl_family2str(uint32_t family);
> int nftnl_str2family(const char *family);
>
> diff --git a/src/expr/counter.c b/src/expr/counter.c
> index 89a602e..fb036dd 100644
> --- a/src/expr/counter.c
> +++ b/src/expr/counter.c
> @@ -35,10 +35,10 @@ nftnl_expr_counter_set(struct nftnl_expr *e, uint16_t type,
>
> switch(type) {
> case NFTNL_EXPR_CTR_BYTES:
> - memcpy(&ctr->bytes, data, sizeof(ctr->bytes));
> + memcpy(&ctr->bytes, data, MIN(data_len, sizeof(ctr->bytes)));
> break;
> case NFTNL_EXPR_CTR_PACKETS:
> - memcpy(&ctr->pkts, data, sizeof(ctr->pkts));
> + memcpy(&ctr->pkts, data, MIN(data_len, sizeof(ctr->pkts)));
> break;
> default:
> return -1;
> --
> 2.29.2
>
