From: Robert Richter <rric@kernel.org>
To: Len Baker <len.baker@gmx.com>
Cc: Kees Cook <keescook@chromium.org>, Borislav Petkov <bp@alien8.de>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
Tony Luck <tony.luck@intel.com>,
James Morse <james.morse@arm.com>,
linux-hardening@vger.kernel.org, linux-edac@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] drivers/edac/edac_mc: Remove all strcpy() uses
Date: Tue, 27 Jul 2021 14:38:47 +0200 [thread overview]
Message-ID: <YP/+V90D6zyxnSyU@rric.localdomain> (raw)
In-Reply-To: <20210725162954.9861-1-len.baker@gmx.com>
On 25.07.21 18:29:54, Len Baker wrote:
> strcpy() performs no bounds checking on the destination buffer. This
> could result in linear overflows beyond the end of the buffer, leading
> to all kinds of misbehaviors. The safe replacement is strscpy().
>
> However, to add labels is better to use the scnprintf to simplify the
> arithmetic.
>
> This is a previous step in the path to remove the strcpy() function
> entirely from the kernel.
>
> Signed-off-by: Len Baker <len.baker@gmx.com>
> ---
> This is a task of the KSPP [1]
>
> [1] https://github.com/KSPP/linux/issues/88
>
> drivers/edac/edac_mc.c | 16 ++++++++--------
> 1 file changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/edac/edac_mc.c b/drivers/edac/edac_mc.c
> index f6d462d0be2d..1286364f0e48 100644
> --- a/drivers/edac/edac_mc.c
> +++ b/drivers/edac/edac_mc.c
> @@ -1027,6 +1027,7 @@ void edac_mc_handle_error(const enum hw_event_mc_err_type type,
> {
> struct dimm_info *dimm;
> char *p;
> + size_t p_size = 0;
I would rather use a 'left' variable which is initialized with
sizeof(e->label) close to there p = e->label is.
> int row = -1, chan = -1;
> int pos[EDAC_MAX_LAYERS] = { top_layer, mid_layer, low_layer };
> int i, n_labels = 0;
> @@ -1113,12 +1114,11 @@ void edac_mc_handle_error(const enum hw_event_mc_err_type type,
> p = e->label;
> *p = '\0';
> } else {
> - if (p != e->label) {
> - strcpy(p, OTHER_LABEL);
> - p += strlen(OTHER_LABEL);
> - }
> - strcpy(p, dimm->label);
> - p += strlen(p);
> + const char *or = (p != e->label) ? OTHER_LABEL : "";
> +
> + p_size += scnprintf(p + p_size,
> + sizeof(e->label) - p_size,
> + "%s%s", or, dimm->label);
My preference is to advance p here (and decrement 'left'). This is the
pattern how p is used throughout the code. I also don't see a benefit
of using scnprintf() here compared to the previous implementation.
Thanks,
-Robert
> }
>
> /*
> @@ -1140,9 +1140,9 @@ void edac_mc_handle_error(const enum hw_event_mc_err_type type,
> }
>
> if (any_memory)
> - strcpy(e->label, "any memory");
> + strscpy(e->label, "any memory", sizeof(e->label));
> else if (!*e->label)
> - strcpy(e->label, "unknown memory");
> + strscpy(e->label, "unknown memory", sizeof(e->label));
>
> edac_inc_csrow(e, row, chan);
>
> --
> 2.25.1
>
next prev parent reply other threads:[~2021-07-27 12:38 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-25 16:29 [PATCH] drivers/edac/edac_mc: Remove all strcpy() uses Len Baker
2021-07-27 12:38 ` Robert Richter [this message]
2021-07-31 15:57 ` Len Baker
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=YP/+V90D6zyxnSyU@rric.localdomain \
--to=rric@kernel.org \
--cc=bp@alien8.de \
--cc=james.morse@arm.com \
--cc=keescook@chromium.org \
--cc=len.baker@gmx.com \
--cc=linux-edac@vger.kernel.org \
--cc=linux-hardening@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.