On 07:11 Tue 31 Oct , Michael S. Tsirkin wrote:
> Quoting r. Sasha Khapyorsky <[EMAIL PROTECTED]>:
> > Subject: Re: [PATCH] diags/saquery: fix node_desc.description as string
> > usages
> >
> > On 06:30 Tue 31 Oct , Michael S. Tsirkin wrote:
> > > Quoting r. Sasha Khapyorsky <[EMAIL PROTECTED]>:
> > > > Subject: Re: [PATCH] diags/saquery: fix node_desc.description as string
> > > > usages
> > > >
> > > > On 13:44 Mon 30 Oct , Michael S. Tsirkin wrote:
> > > > > Quoting r. Sasha Khapyorsky <[EMAIL PROTECTED]>:
> > > > > > Subject: [PATCH] diags/saquery: fix node_desc.description as string
> > > > > > usages
> > > > > >
> > > > > >
> > > > > > node_desc.description buffer is received from the network and should
> > > > > > not be NULL-terminated. In such cases using it as regular string in
> > > > > > functions like strcmp() or printf() leads to segmentation faults.
> > > > > > This patch fixes such usages.
> > > > > >
> > > > > > Signed-off-by: Sasha Khapyorsky <[EMAIL PROTECTED]>
> > > > > > ---
> > > > > > diags/src/saquery.c | 22 ++++++++++++++++------
> > > > > > 1 files changed, 16 insertions(+), 6 deletions(-)
> > > > > >
> > > > > > diff --git a/diags/src/saquery.c b/diags/src/saquery.c
> > > > > > index 5b4a85e..f5b23fd 100644
> > > > > > --- a/diags/src/saquery.c
> > > > > > +++ b/diags/src/saquery.c
> > > > > > @@ -90,17 +90,21 @@ static void
> > > > > > print_node_desc(ib_node_record_t *node_record)
> > > > > > {
> > > > > > ib_node_info_t *p_ni = &(node_record->node_info);
> > > > > > + ib_node_desc_t *p_nd = &(node_record->node_desc);
> > > > > > if (p_ni->node_type == IB_NODE_TYPE_CA)
> > > > > > {
> > > > > > + char desc[sizeof(p_nd->description) + 1];
> > > > > > + memcpy(desc, p_nd->description,
> > > > > > sizeof(p_nd->description));
> > > > > > + desc[sizeof(desc) - 1] = '\0';
> > > > > > printf("%6d \"%s\"\n",
> > > > > > - cl_ntoh16(node_record->lid),
> > > > > > - node_record->node_desc.description);
> > > > > > + cl_ntoh16(node_record->lid), desc);
> > > > > > }
> > > > > > }
> > > > >
> > > > > Would it not be simpler, and cleaner, to limit the string width in
> > > > > printf:
> > > > > printf("%6d \"%.*s\"\n",
> > > > > cl_ntoh16(node_record->lid),
> > > > > sizeof(desc),
> > > > > node_record->node_desc.description);
> > > >
> > > > This would be simpler. However some web searching shows that not all
> > > > printf() implementation permits not null terminated arrays even when
> > > > precision is specified (some issues were reported even with
> > > > glibc-2.3.2).
> > >
> > > Hmm, couldn't find it.
> >
> > Look at this for example:
> > http://sourceware.org/ml/bug-glibc/2005-02/msg00123.html
>
> Hmm, yea. Do you understand the answer there?
> Does not make sense to me ...
I less care about the answer, but more about valgrind output (btw
cannot see this with glibc-2.5) and similar "corner case" issues.
Sasha
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