netdev - Re: [PATCH ethtool-next 1/7] cmis: Fix CLEI code parsing

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20210930211204.3lcghvpe5xn4p2za@lion.mk-sys.cz>
Date:   Thu, 30 Sep 2021 23:12:04 +0200
From:   Michal Kubecek <mkubecek@...e.cz>
To:     Ido Schimmel <idosch@...sch.org>
Cc:     netdev@...r.kernel.org, vadimp@...dia.com, moshe@...dia.com,
        popadrian1996@...il.com, mlxsw@...dia.com,
        Ido Schimmel <idosch@...dia.com>
Subject: Re: [PATCH ethtool-next 1/7] cmis: Fix CLEI code parsing

On Thu, Sep 30, 2021 at 11:41:02PM +0300, Ido Schimmel wrote:
> On Thu, Sep 30, 2021 at 10:21:33PM +0200, Michal Kubecek wrote:
> > On Fri, Sep 17, 2021 at 05:40:37PM +0300, Ido Schimmel wrote:
> > > From: Ido Schimmel <idosch@...dia.com>
> > > 
> > > In CMIS, unlike SFF-8636, there is no presence indication for the CLEI
> > > code (Common Language Equipment Identification) field. The field is
> > > always present, but might not be supported. In which case, "a value of
> > > all ASCII 20h (spaces) shall be entered".
> > > 
> > > Therefore, remove the erroneous check which seems to be influenced from
> > > SFF-8636 and only print the string if it is supported and has a non-zero
> > > length.
> > > 
> > > Signed-off-by: Ido Schimmel <idosch@...dia.com>
> > > ---
> > >  cmis.c | 8 +++++---
> > >  cmis.h | 3 +--
> > >  2 files changed, 6 insertions(+), 5 deletions(-)
> > > 
> > > diff --git a/cmis.c b/cmis.c
> > > index 1a91e798e4b8..2a48c1a1d56a 100644
> > > --- a/cmis.c
> > > +++ b/cmis.c
> > > @@ -307,6 +307,8 @@ static void cmis_show_link_len(const __u8 *id)
> > >   */
> > >  static void cmis_show_vendor_info(const __u8 *id)
> > >  {
> > > +	const char *clei = (const char *)(id + CMIS_CLEI_START_OFFSET);
> > > +
> > >  	sff_show_ascii(id, CMIS_VENDOR_NAME_START_OFFSET,
> > >  		       CMIS_VENDOR_NAME_END_OFFSET, "Vendor name");
> > >  	cmis_show_oui(id);
> > > @@ -319,9 +321,9 @@ static void cmis_show_vendor_info(const __u8 *id)
> > >  	sff_show_ascii(id, CMIS_DATE_YEAR_OFFSET,
> > >  		       CMIS_DATE_VENDOR_LOT_OFFSET + 1, "Date code");
> > >  
> > > -	if (id[CMIS_CLEI_PRESENT_BYTE] & CMIS_CLEI_PRESENT_MASK)
> > > -		sff_show_ascii(id, CMIS_CLEI_START_OFFSET,
> > > -			       CMIS_CLEI_END_OFFSET, "CLEI code");
> > > +	if (strlen(clei) && strcmp(clei, CMIS_CLEI_BLANK))
> > > +		sff_show_ascii(id, CMIS_CLEI_START_OFFSET, CMIS_CLEI_END_OFFSET,
> > > +			       "CLEI code");
> > >  }
> > >  
> > >  void qsfp_dd_show_all(const __u8 *id)
> > 
> > Is it safe to assume that the string will be always null terminated?
> 
> No. You want to see strnlen() and strncmp() instead?

Yes, that would solve the problem. Actually, "strlen(clei)" could be
also replaced with "*clei" or "clei[0]" as a string is empty if and only
if its first byte is null.

Michal

> > Looking at the code below, CMIS_CLEI_BLANK consists of 10 spaces which
> > would fill the whole block at offsets 0xBE through 0xC7 with spaces and
> > offset 0xC8 is used as CMIS_PWR_CLASS_OFFSET. Also, sff_show_ascii()
> > doesn't seem to expect a null terminated string, rather a space padded
> > one.

Download attachment "signature.asc" of type "application/pgp-signature" (489 bytes)