On 4/1/2022 3:50 AM, Lee Jones wrote:
> Checks are presently in place in validate_nla() to ensure strings
> greater than 2 are not passed in by the user which could potentially
> cause issues.
>
> However, there is nothing to prevent userspace from only providing a
> single (1) Byte as the data length parameter via nla_put(). If this
> were to happen, it would cause an OOB read in regulatory_hint_user(),
> since it makes assumptions that alpha2[0] and alpha2[1] will always be
> accessible.
>
> Add an additional check, to ensure enough data has been allocated to
> hold both Bytes.
>
> Cc: <[email protected]>
> Cc: Johannes Berg <[email protected]>
> Cc: "David S. Miller" <[email protected]>
> Cc: Jakub Kicinski <[email protected]>
> Cc: Paolo Abeni <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Signed-off-by: Lee Jones <[email protected]>
> ---
> net/wireless/nl80211.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
> index ee1c2b6b69711..80a516033db36 100644
> --- a/net/wireless/nl80211.c
> +++ b/net/wireless/nl80211.c
> @@ -7536,6 +7536,10 @@ static int nl80211_req_set_reg(struct sk_buff *skb, struct genl_info *info)
> if (!info->attrs[NL80211_ATTR_REG_ALPHA2])
> return -EINVAL;
>
> + if (nla_len(info->attrs[NL80211_ATTR_REG_ALPHA2]) !=
> + nl80211_policy[NL80211_ATTR_REG_ALPHA2].len)
> + return -EINVAL;
> +
> data = nla_data(info->attrs[NL80211_ATTR_REG_ALPHA2]);
> return regulatory_hint_user(data, user_reg_hint_type);
> case NL80211_USER_REG_HINT_INDOOR:
LGTM
doesn't nl80211_set_reg() also have this issue?
alpha2 = nla_data(info->attrs[NL80211_ATTR_REG_ALPHA2]);
[...]
rd->alpha2[0] = alpha2[0];
rd->alpha2[1] = alpha2[1];