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Date:   Wed, 25 Oct 2023 23:40:34 +0000
In-Reply-To: <20231025-ethtool_puts_impl-v1-0-6a53a93d3b72@google.com>
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Subject: [PATCH 3/3] checkpatch: add ethtool_sprintf rules
From:   Justin Stitt <justinstitt@google.com>
To:     "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Shay Agroskin <shayagr@amazon.com>,
        Arthur Kiyanovski <akiyano@amazon.com>,
        David Arinzon <darinzon@amazon.com>,
        Noam Dagan <ndagan@amazon.com>,
        Saeed Bishara <saeedb@amazon.com>,
        Rasesh Mody <rmody@marvell.com>,
        Sudarsana Kalluru <skalluru@marvell.com>,
        GR-Linux-NIC-Dev@marvell.com,
        Dimitris Michailidis <dmichail@fungible.com>,
        Yisen Zhuang <yisen.zhuang@huawei.com>,
        Salil Mehta <salil.mehta@huawei.com>,
        Jesse Brandeburg <jesse.brandeburg@intel.com>,
        Tony Nguyen <anthony.l.nguyen@intel.com>,
        Louis Peens <louis.peens@corigine.com>,
        Shannon Nelson <shannon.nelson@amd.com>,
        Brett Creeley <brett.creeley@amd.com>, drivers@pensando.io,
        "K. Y. Srinivasan" <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Wei Liu <wei.liu@kernel.org>, Dexuan Cui <decui@microsoft.com>,
        Ronak Doshi <doshir@vmware.com>,
        VMware PV-Drivers Reviewers <pv-drivers@vmware.com>,
        Andy Whitcroft <apw@canonical.com>,
        Joe Perches <joe@perches.com>,
        Dwaipayan Ray <dwaipayanray1@gmail.com>,
        Lukas Bulwahn <lukas.bulwahn@gmail.com>
Cc:     linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
        Nick Desaulniers <ndesaulniers@google.com>,
        Nathan Chancellor <nathan@kernel.org>,
        Kees Cook <keescook@chromium.org>,
        intel-wired-lan@lists.osuosl.org, oss-drivers@corigine.com,
        linux-hyperv@vger.kernel.org, Justin Stitt <justinstitt@google.com>
Content-Type: text/plain; charset="utf-8"
Precedence: bulk

Add some warnings for using ethtool_sprintf() where a simple
ethtool_puts() would suffice.

The two cases are:

1) Use ethtool_sprintf() with just two arguments:
|       ethtool_sprintf(&data, driver[i].name);
or
2) Use ethtool_sprintf() with a standalone "%s" fmt string:
|       ethtool_sprintf(&data, "%s", driver[i].name);

The former may cause -Wformat-security warnings while the latter is just
not preferred. Both are safely in the category of warnings, not errors.

Signed-off-by: Justin Stitt <justinstitt@google.com>
---
 scripts/checkpatch.pl | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 7d16f863edf1..1ba9ce778746 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -7020,6 +7020,19 @@ sub process {
 			     "Prefer strscpy, strscpy_pad, or __nonstring over strncpy - see: https://github.com/KSPP/linux/issues/90\n" . $herecurr);
 		}
 
+# ethtool_sprintf uses that should likely be ethtool_puts
+		if (   $line =~ /\bethtool_sprintf\s*\(\s*$FuncArg\s*,\s*$FuncArg\s*\)/   ) {
+			WARN("ETHTOOL_SPRINTF",
+			     "Prefer ethtool_puts over ethtool_sprintf with only two arguments" . $herecurr);
+		}
+
+		# use $rawline because $line loses %s via sanitization and thus we can't match against it.
+		if (   $rawline =~ /\bethtool_sprintf\s*\(\s*$FuncArg\s*,\s*\"\%s\"\s*,\s*$FuncArg\s*\)/   ) {
+			WARN("ETHTOOL_SPRINTF2",
+			     "Prefer ethtool_puts over ethtool_sprintf with standalone \"%s\" specifier" . $herecurr);
+		}
+
+
 # typecasts on min/max could be min_t/max_t
 		if ($perl_version_ok &&
 		    defined $stat &&

-- 
2.42.0.758.gaed0368e0e-goog