Re: [PATCH net v2 0/3] rtnetlink: fix truncation of dump entry

[Hangbin Liu <hangbin.liu@linux.dev>]

On Tue, Nov 10, 2026 at 09:26:15AM -0800, Stephen Hemminger wrote:
> While analyzing one of the OSS Scanner dump reports for iproute2,
> a bug was uncovered in netlink route dump.
> A route dump whose first entry is too large for the dump skb ends with
> NLMSG_DONE and status 0. The route and everything after it is silently
> dropped; "ip route show table 100" prints nothing and exits 0.
> 
> It takes some non real world stuff to do this 
> like a 500 way multipath route is enough to trigger this.
> 
> The series is broken into three parts:
>   1. Fix regression in rtnl_dumpit().
>      Do not hide EMSGSIZE on empty skb case.
>   2. Fix IPv6 FIB dump to propagate error properly
>   3. Add a test for this bug.
> 
> v2 - drop Assisted-by
>    - correct commit message about "ip route get"
> 
> Stephen Hemminger (3):
>   rtnetlink: return EMSGSIZE when first dump entry does not fit
>   ipv6: return EMSGSIZE when first route in dump does not fit
>   selftests: net: netlink-dumps: test dump of route larger than skb
> 
>  net/core/rtnetlink.c                        |   5 +-
>  net/ipv6/ip6_fib.c                          |   6 +
>  tools/testing/selftests/net/config          |   3 +
>  tools/testing/selftests/net/netlink-dumps.c | 271 +++++++++++++++++++-
>  4 files changed, 280 insertions(+), 5 deletions(-)
> 
> -- 
> 2.53.0
> 

For the series

Tested-by: Hangbin Liu <liuhangbin@kylinos.cn>
Reviewed-by: Hangbin Liu <liuhangbin@kylinos.cn>