> -----Original Message-----
> From: Richardson, Bruce
> Sent: Monday 23 October 2017 13:58
> To: Rybalchenko, Kirill <kirill.rybalche...@intel.com>
> Cc: dev@dpdk.org; Chilikin, Andrey <andrey.chili...@intel.com>; Xing, Beilei
> <beilei.x...@intel.com>; Wu, Jingjing <jingjing...@intel.com>
> Subject: Re: [dpdk-dev] [PATCH] net/i40e: fix value of num parameter for
> strncpy function
>
> On Mon, Oct 23, 2017 at 12:24:49PM +0100, Kirill Rybalchenko wrote:
> > num parameter for strncpy() function should be smaller than actual
> > destination buffer size to allow null termination.
> >
> > Fixes: 40d1324423a4 ("net/i40e: get ddp profile protocol info")
> >
> > Signed-off-by: Kirill Rybalchenko <kirill.rybalche...@intel.com>
> > ---
> > drivers/net/i40e/rte_pmd_i40e.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/i40e/rte_pmd_i40e.c
> > b/drivers/net/i40e/rte_pmd_i40e.c index 4881ea0..489f66b 100644
> > --- a/drivers/net/i40e/rte_pmd_i40e.c
> > +++ b/drivers/net/i40e/rte_pmd_i40e.c
> > @@ -1928,7 +1928,7 @@ int rte_pmd_i40e_get_ddp_info(uint8_t
> *pkg_buff, uint32_t pkg_size,
> > for (i = j = 0; i < nb_rec; j++) {
> > pinfo[j].proto_id = tlv->data[0];
> > strncpy(pinfo[j].name, (const char *)&tlv->data[1],
> > - I40E_DDP_NAME_SIZE);
> > + I40E_DDP_NAME_SIZE - 1);
> > i += tlv->len;
> > tlv = &tlv[tlv->len];
> > }
> > --
>
> This is not a proper fix, as it still won't null-terminate the result.
> Replace strncpy with snprintf is probably the best solution.
The source buffer is 12 bytes long and guaranteed contains null-terminated
C-string,
Destination buffer is 32 bytes long. Strncpy documentation says:
" Copies the first num characters of source to destination. If the end of the
source C string (which is signaled by a null-character) is found before num
characters have been copied, destination is padded with zeros until a total of
num characters have been written to it."
I belive, having that, we can be sure that we'll get proper null-terminated
string within destination buffer.
Or do I miss something?
>
> /Bruce
