[ovs-dev] [PATCH] dpif-netlink: fix null pointer

[Matteo Croce]

On Mon, Oct 8, 2018 at 3:11 PM Guru Shetty <guru at ovn.org> wrote:
>
>
>
> On Sat, 6 Oct 2018 at 09:20, Matteo Croce <mcroce at redhat.com> wrote:
>>
>> In dpif_netlink_port_add__(), socksp could be NULL, because
>> vport_socksp_to_pids() would allocate a new array and return a single
>> zero element.
>> Following vport_socksp_to_pids() removal, a NULL pointer can happen when
>> dpif_netlink_port_add__() is called and dpif->handlers is 0.
>>
>> Restore the old behaviour of using a zero pid when dpif->handlers is 0.
>>
>> Fixes: 69c51582f ("dpif-netlink: don't allocate per thread netlink sockets")
>> Reported-by: Flavio Leitner <fbl at redhat.com>
>> Reported-by: Guru Shetty <guru at ovn.org>
>> Signed-off-by: Matteo Croce <mcroce at redhat.com>
>> ---
>
>
> Not a review of the code. But I can confirm that the patch does fix the segmentation fault that I was facing.
>
>>
>>  lib/dpif-netlink.c | 5 +++--
>>  1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/lib/dpif-netlink.c b/lib/dpif-netlink.c
>> index 21315033c..310bc947d 100644
>> --- a/lib/dpif-netlink.c
>> +++ b/lib/dpif-netlink.c
>> @@ -712,7 +712,7 @@ dpif_netlink_port_add__(struct dpif_netlink *dpif, const char *name,
>>      struct dpif_netlink_vport request, reply;
>>      struct ofpbuf *buf;
>>      struct nl_sock *socksp = NULL;
>> -    uint32_t upcall_pids;
>> +    uint32_t upcall_pids = 0;
>>      int error = 0;
>>
>>      if (dpif->handlers) {
>> @@ -728,7 +728,8 @@ dpif_netlink_port_add__(struct dpif_netlink *dpif, const char *name,
>>      request.name = name;
>>
>>      request.port_no = *port_nop;
>> -    upcall_pids = nl_sock_pid(socksp);
>> +    if (socksp)
>> +        upcall_pids = nl_sock_pid(socksp);
>>      request.n_upcall_pids = 1;
>>      request.upcall_pids = &upcall_pids;
>>
>> --
>> 2.17.1
>>

Ok thanks. I'me sending a v2 with the checkpatch.py warning found by
Aaron's bot fixed

-- 
Matteo Croce
per aspera ad upstream