[ovs-dev] [PATCHv3] netlink: added check to prevent netlink attribute overflow

[Gregory Rose]

On 2/19/2019 10:55 AM, Toms Atteka wrote:
> If enough large input is passed to odp_actions_from_string it can
> cause netlink attribute to overflow.
> Check for buffer size was added to prevent entering this function
> and returning appropriate error code.
>
> Basic manual testing was performed.
>
> Reported-by:
> https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=12231
> Signed-off-by: Toms Atteka <cpp.code.lv at gmail.com>
> ---
>   lib/odp-util.c | 4 ++++
>   1 file changed, 4 insertions(+)
>
> diff --git a/lib/odp-util.c b/lib/odp-util.c
> index e893f46..e288ae8 100644
> --- a/lib/odp-util.c
> +++ b/lib/odp-util.c
> @@ -2161,6 +2161,10 @@ parse_action_list(const char *s, const struct simap *port_names,
>           n += retval;
>       }
>   
> +    if (actions->size > UINT16_MAX) {
> +        return -EFBIG;
> +    }
> +
>       return n;
>   }
>   
Hi Toms,

Thanks for the patch.  Question though, why EFBIG instead of E2BIG? This 
would appear to be a situation in
which too many arguments are sent (E2BIG) but then maybe it is from a 
file (EFBIG)?

Also, I see this is a version 3 of this patch?  What changed from 
version 1 to version 3?  Commonly the
changes from each version of a patch are posted beneath the git 
separator '---'.  Like below...

Thanks,

- Greg

Signed-off-by: Martin Xu <martinxu9.ovs at gmail.com>
CC: Flavio Leitner <fbl at sysclose.org>

CC: Yi-Hung Wei <yihung.wei at gmail.com> CC: Yifeng Sun 
<pkusunyifeng at gmail.com> CC: Zak Whittington <zwhitt.vmware at gmail.com> 
CC: Ben Pfaff <blp at ovn.org> --- v1->v2: adds "Obsoletes" tag needed for 
upgrade after renaming adds more reviewers