From: Robert Richter <rrichter@marvell.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>,
Tony Luck <tony.luck@intel.com>,
James Morse <james.morse@arm.com>,
Aristeu Rozanski <aris@redhat.com>,
Matthias Brugger <mbrugger@suse.com>,
<linux-edac@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 01/10] EDAC/mc: Fix usage of snprintf() and dimm location setup
Date: Tue, 19 May 2020 11:27:48 +0200 [thread overview]
Message-ID: <20200519092748.zalds3reudd22nky@rric.localdomain> (raw)
In-Reply-To: <20200422205243.GH26846@zn.tnic>
On 22.04.20 22:52:43, Borislav Petkov wrote:
> On Wed, Apr 22, 2020 at 01:58:05PM +0200, Robert Richter wrote:
> > The setup of the dimm->location may be incomplete in case writing to
> > dimm->label fails due to small buffer size. Fix this by iterating
> > through all existing layers.
> >
> > Also, the return value of snprintf() can be higher than the number of
> > bytes written to the buffer in case it is to small. Fix usage of
> > snprintf() by either porting it to scnprintf() or fixing the handling
> > of the return code.
> >
> > It is very unlikely the buffer is too small in practice, but fixing it
> > anyway.
> >
> > Signed-off-by: Robert Richter <rrichter@marvell.com>
> > ---
> > drivers/edac/edac_mc.c | 20 ++++++++++----------
> > 1 file changed, 10 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/edac/edac_mc.c b/drivers/edac/edac_mc.c
> > index 75ede27bdf6a..107d7c4de933 100644
> > --- a/drivers/edac/edac_mc.c
> > +++ b/drivers/edac/edac_mc.c
> > @@ -130,11 +130,11 @@ unsigned int edac_dimm_info_location(struct dimm_info *dimm, char *buf,
> > n = snprintf(p, len, "%s %d ",
> > edac_layer_name[mci->layers[i].type],
> > dimm->location[i]);
> > + if (len <= n)
> > + return count + len - 1;
> > p += n;
> > len -= n;
> > count += n;
> > - if (!len)
> > - break;
> > }
> >
> > return count;
> > @@ -397,19 +397,19 @@ static int edac_mc_alloc_dimms(struct mem_ctl_info *mci)
> > */
> > len = sizeof(dimm->label);
> > p = dimm->label;
> > - n = snprintf(p, len, "mc#%u", mci->mc_idx);
> > + n = scnprintf(p, len, "mc#%u", mci->mc_idx);
> > p += n;
> > len -= n;
> > +
> > for (layer = 0; layer < mci->n_layers; layer++) {
> > - n = snprintf(p, len, "%s#%u",
> > - edac_layer_name[mci->layers[layer].type],
> > - pos[layer]);
>
> The edac_layer_name[]'s are single words of a couple of letters and the
> pos is a number. The buffer we pass in is at least 80 chars and in one
> place even a PAGE_SIZE.
>
> But in general, this is just silly with the buffers on stack and
> printing into them.
>
> It would be much better to opencode that loop in
> edac_dimm_info_location() and simply dump those layer names at the call
> sites. And then kill that silly edac_dimm_info_location() function. See
> below for example.
>
> And then since two call sites do edac_dbg(), you can put that in a
> function edac_dbg_dump_dimm_location() or so and call it and not care
> about any buffer lengths and s*printf's and so on.
>
> Right?
The aim of this patch is just to fix snprintf() users. Anything else
would involve a larger cleanup. It is not only about edac_dbg(), there
are other users of edac_layer_name[] which implement similar things
that need to be looked at.
So I am dropping this patch from the series.
Thanks,
-Robert
next prev parent reply other threads:[~2020-05-19 9:28 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-22 11:58 [PATCH v2 00/10] EDAC/mc/ghes: Fixes, cleanup and reworks Robert Richter
2020-04-22 11:58 ` [PATCH v2 01/10] EDAC/mc: Fix usage of snprintf() and dimm location setup Robert Richter
2020-04-22 20:52 ` Borislav Petkov
2020-05-19 9:27 ` Robert Richter [this message]
2020-04-22 11:58 ` [PATCH v2 02/10] EDAC/mc: Use int type for parameters of edac_mc_alloc() Robert Richter
2020-04-23 17:49 ` Borislav Petkov
2020-05-19 9:33 ` Robert Richter
2020-04-22 11:58 ` [PATCH v2 03/10] EDAC/ghes: Remove unused members of struct ghes_edac_pvt, rename it to ghes_mci Robert Richter
2020-04-23 17:55 ` Borislav Petkov
2020-05-05 7:50 ` Robert Richter
2020-04-22 11:58 ` [PATCH v2 04/10] EDAC/ghes: Make SMBIOS handle private data to ghes Robert Richter
2020-04-24 12:12 ` kbuild test robot
2020-04-24 16:21 ` Borislav Petkov
2020-05-05 12:48 ` Robert Richter
2020-04-22 11:58 ` [PATCH v2 05/10] EDAC/ghes: Setup DIMM label from DMI and use it in error reports Robert Richter
2020-04-22 11:58 ` [PATCH v2 06/10] EDAC/ghes: Remove local variable rdr_mask in ghes_edac_dmidecode() Robert Richter
2020-04-27 7:08 ` Borislav Petkov
2020-04-27 17:24 ` Luck, Tony
2020-04-27 17:34 ` Borislav Petkov
2020-05-19 9:34 ` Robert Richter
2020-04-22 11:58 ` [PATCH v2 07/10] EDAC/ghes: Cleanup struct ghes_edac_dimm_fill, rename it to ghes_dimm_fill Robert Richter
2020-04-27 14:00 ` Borislav Petkov
2020-05-19 9:35 ` Robert Richter
2020-04-22 11:58 ` [PATCH v2 08/10] EDAC/ghes: Carve out MC device handling into separate functions Robert Richter
2020-04-27 16:38 ` Borislav Petkov
2020-05-06 8:45 ` Robert Richter
2020-05-11 13:32 ` Borislav Petkov
2020-05-19 9:57 ` Robert Richter
2020-04-22 11:58 ` [PATCH v2 09/10] EDAC/ghes: Have a separate code path for creating the fake MC Robert Richter
2020-04-22 11:58 ` [PATCH v2 10/10] EDAC/ghes: Carve out code into ghes_edac_register_{one,fake}() Robert Richter
2020-05-06 8:53 ` [PATCH v2 00/10] EDAC/mc/ghes: Fixes, cleanup and reworks Robert Richter
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200519092748.zalds3reudd22nky@rric.localdomain \
--to=rrichter@marvell.com \
--cc=aris@redhat.com \
--cc=bp@alien8.de \
--cc=james.morse@arm.com \
--cc=linux-edac@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mbrugger@suse.com \
--cc=mchehab@kernel.org \
--cc=tony.luck@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).