On Thu, Jan 11, 2024 at 11:25:27PM +0100, Pablo Neira Ayuso wrote:
> Allow to set a maximum limit of sizeof(s->desc.field_len) which is 16
> bytes, otherwise, bail out. Ensure s->desc.field_count does not go over
> the array boundary.
>
> Fixes: 7cd41b5387ac ("set: Add support for NFTA_SET_DESC_CONCAT attributes")
> Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
> ---
> src/set.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/src/set.c b/src/set.c
> index 719e59616e97..b51ff9e0ba64 100644
> --- a/src/set.c
> +++ b/src/set.c
> @@ -194,8 +194,14 @@ int nftnl_set_set_data(struct nftnl_set *s, uint16_t attr, const void *data,
> memcpy(&s->desc.size, data, sizeof(s->desc.size));
> break;
> case NFTNL_SET_DESC_CONCAT:
> + if (data_len > sizeof(s->desc.field_len))
> + return -1;
> +
> memcpy(&s->desc.field_len, data, data_len);
> - while (s->desc.field_len[++s->desc.field_count]);
> + while (s->desc.field_len[++s->desc.field_count]) {
> + if (s->desc.field_count >= NFT_REG32_COUNT)
> + break;
> + }
Isn't the second check redundant if you adjust the first one like so:
| if (data_len >= sizeof(s->desc.field_len))
Or more explicit:
| if (data_len > sizeof(s->desc.field_len) -
| sizeof(s->desc.field_len[0]))
Cheers, Phil
