All of lore.kernel.org
 help / color / mirror / Atom feed
From: Justin Stitt <justinstitt@google.com>
To: Jesse Brandeburg <jesse.brandeburg@intel.com>,
	Tony Nguyen <anthony.l.nguyen@intel.com>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>
Cc: intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org,
	Justin Stitt <justinstitt@google.com>
Subject: [PATCH] i40e: use scnprintf over strncpy+strncat
Date: Tue, 10 Oct 2023 20:53:00 +0000	[thread overview]
Message-ID: <20231010-strncpy-drivers-net-ethernet-intel-i40e-i40e_ddp-c-v1-1-f01a23394eab@google.com> (raw)

`strncpy` is deprecated for use on NUL-terminated destination strings
[1] and as such we should prefer more robust and less ambiguous string
interfaces.

Moreover, `strncat` shouldn't really be used either as per
fortify-string.h:
 * Do not use this function. While FORTIFY_SOURCE tries to avoid
 * read and write overflows, this is only possible when the sizes
 * of @p and @q are known to the compiler. Prefer building the
 * string with formatting, via scnprintf() or similar.

Instead, use `scnprintf` with "%s%s" format string. This code is now
more readable and robust.

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2]
Link: https://github.com/KSPP/linux/issues/90
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Justin Stitt <justinstitt@google.com>
---
Note: build-tested only.
---
 drivers/net/ethernet/intel/i40e/i40e_ddp.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_ddp.c b/drivers/net/ethernet/intel/i40e/i40e_ddp.c
index 0e72abd178ae..ec25e4be250f 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_ddp.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_ddp.c
@@ -438,10 +438,9 @@ int i40e_ddp_flash(struct net_device *netdev, struct ethtool_flash *flash)
 		char profile_name[sizeof(I40E_DDP_PROFILE_PATH)
 				  + I40E_DDP_PROFILE_NAME_MAX];
 
-		profile_name[sizeof(profile_name) - 1] = 0;
-		strncpy(profile_name, I40E_DDP_PROFILE_PATH,
-			sizeof(profile_name) - 1);
-		strncat(profile_name, flash->data, I40E_DDP_PROFILE_NAME_MAX);
+		scnprintf(profile_name, sizeof(profile_name), "%s%s",
+			  I40E_DDP_PROFILE_PATH, flash->data);
+
 		/* Load DDP recipe. */
 		status = request_firmware(&ddp_config, profile_name,
 					  &netdev->dev);

---
base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2
change-id: 20231010-strncpy-drivers-net-ethernet-intel-i40e-i40e_ddp-c-dd7f20b7ed5d

Best regards,
--
Justin Stitt <justinstitt@google.com>


WARNING: multiple messages have this Message-ID (diff)
From: Justin Stitt <justinstitt@google.com>
To: Jesse Brandeburg <jesse.brandeburg@intel.com>,
	Tony Nguyen <anthony.l.nguyen@intel.com>,
	 "David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	 Jakub Kicinski <kuba@kernel.org>,
	Paolo Abeni <pabeni@redhat.com>
Cc: netdev@vger.kernel.org, Justin Stitt <justinstitt@google.com>,
	intel-wired-lan@lists.osuosl.org, linux-kernel@vger.kernel.org,
	linux-hardening@vger.kernel.org
Subject: [Intel-wired-lan] [PATCH] i40e: use scnprintf over strncpy+strncat
Date: Tue, 10 Oct 2023 20:53:00 +0000	[thread overview]
Message-ID: <20231010-strncpy-drivers-net-ethernet-intel-i40e-i40e_ddp-c-v1-1-f01a23394eab@google.com> (raw)

`strncpy` is deprecated for use on NUL-terminated destination strings
[1] and as such we should prefer more robust and less ambiguous string
interfaces.

Moreover, `strncat` shouldn't really be used either as per
fortify-string.h:
 * Do not use this function. While FORTIFY_SOURCE tries to avoid
 * read and write overflows, this is only possible when the sizes
 * of @p and @q are known to the compiler. Prefer building the
 * string with formatting, via scnprintf() or similar.

Instead, use `scnprintf` with "%s%s" format string. This code is now
more readable and robust.

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2]
Link: https://github.com/KSPP/linux/issues/90
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Justin Stitt <justinstitt@google.com>
---
Note: build-tested only.
---
 drivers/net/ethernet/intel/i40e/i40e_ddp.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_ddp.c b/drivers/net/ethernet/intel/i40e/i40e_ddp.c
index 0e72abd178ae..ec25e4be250f 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_ddp.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_ddp.c
@@ -438,10 +438,9 @@ int i40e_ddp_flash(struct net_device *netdev, struct ethtool_flash *flash)
 		char profile_name[sizeof(I40E_DDP_PROFILE_PATH)
 				  + I40E_DDP_PROFILE_NAME_MAX];
 
-		profile_name[sizeof(profile_name) - 1] = 0;
-		strncpy(profile_name, I40E_DDP_PROFILE_PATH,
-			sizeof(profile_name) - 1);
-		strncat(profile_name, flash->data, I40E_DDP_PROFILE_NAME_MAX);
+		scnprintf(profile_name, sizeof(profile_name), "%s%s",
+			  I40E_DDP_PROFILE_PATH, flash->data);
+
 		/* Load DDP recipe. */
 		status = request_firmware(&ddp_config, profile_name,
 					  &netdev->dev);

---
base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2
change-id: 20231010-strncpy-drivers-net-ethernet-intel-i40e-i40e_ddp-c-dd7f20b7ed5d

Best regards,
--
Justin Stitt <justinstitt@google.com>

_______________________________________________
Intel-wired-lan mailing list
Intel-wired-lan@osuosl.org
https://lists.osuosl.org/mailman/listinfo/intel-wired-lan

             reply	other threads:[~2023-10-10 20:53 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-10 20:53 Justin Stitt [this message]
2023-10-10 20:53 ` [Intel-wired-lan] [PATCH] i40e: use scnprintf over strncpy+strncat Justin Stitt
2023-10-10 21:21 ` Jesse Brandeburg
2023-10-10 21:21   ` [Intel-wired-lan] " Jesse Brandeburg
2023-10-10 22:38 ` Justin Stitt
2023-10-10 22:38   ` [Intel-wired-lan] " Justin Stitt

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=20231010-strncpy-drivers-net-ethernet-intel-i40e-i40e_ddp-c-v1-1-f01a23394eab@google.com \
    --to=justinstitt@google.com \
    --cc=anthony.l.nguyen@intel.com \
    --cc=davem@davemloft.net \
    --cc=edumazet@google.com \
    --cc=intel-wired-lan@lists.osuosl.org \
    --cc=jesse.brandeburg@intel.com \
    --cc=kuba@kernel.org \
    --cc=linux-hardening@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=netdev@vger.kernel.org \
    --cc=pabeni@redhat.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.