From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C79E334A3D6; Mon, 17 Nov 2025 20:33:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763411601; cv=none; b=MaO4NXfYkNx1kGetw0JZPaxB3ne5hlYQYTWRxGMPasyHcgNj892jYsfMQ5xHDbAdPVjhyPor0DKn6m3iatsxbn1ivc9GVb8phLJkKPWvYL0ot6XUDtHIZCsx/2P+xDInVHAoj07VZV2UvxggaNUygj6hL8Pl/dcQfog/aDpTAYc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763411601; c=relaxed/simple; bh=BV6A7dBjO90aTngR1VxmTz0Cc3FxYyV4HxPja2tfCrs=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=FRnymgU4uFxkeFHtQgFOizADOIX5fXy92wQtO388geJVqm+631lm4CbnG0D3cJkKByOqxxyoIjsKsjFRITsPSnkrLt8qX4n+cP1Lmi/31hmWwl/Jbth/QgEMnQDDtnF7gc2On4Wnjf6KxXGMjwuSysB47fS12TznfyxNst/6Iao= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=IwaSjFcC; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="IwaSjFcC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A0045C2BC9E; Mon, 17 Nov 2025 20:33:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1763411600; bh=BV6A7dBjO90aTngR1VxmTz0Cc3FxYyV4HxPja2tfCrs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=IwaSjFcC+CJt1Xd6iGnljRiCT+H+mCtIJfZZ+jxJJZkfbreYXobKxC5EnfYfdCvyM VXOFD5hZkGsx1FD6wEeEA6JpLieId9iZyELXldUOu8v3HckxnMs5Ox4ER5yai0fOkh oMwU7JRSZWE8Z3yGFMxd75xXOObKyShqO11/EIefiYWQXwvovomp5j7IAGtAK7IhZj h5nE6uSqqKCABwskWvxtc9x0P+by27/qalo9BDIA+e6xLfGyxmSPaGv6oSACQZO4k+ GjNCqszjwa04QVxS54Zza7rJbTRStyKG+kTv8tdtWSz07/MZJEPf7EaXbE5b6Eilir 7tpoV4h+NIHnA== Date: Mon, 17 Nov 2025 12:33:18 -0800 From: Kees Cook To: Bartosz Golaszewski Cc: Mika Westerberg , Dmitry Torokhov , Andrew Morton , Linus Walleij , Manivannan Sadhasivam , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Saravana Kannan , Greg Kroah-Hartman , Andy Shevchenko , Catalin Marinas , Will Deacon , Srinivas Kandagatla , Liam Girdwood , Mark Brown , Jaroslav Kysela , Takashi Iwai , Alexey Klimov , Bjorn Andersson , Konrad Dybcio , linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-sound@vger.kernel.org, linux-arm-msm@vger.kernel.org, Bartosz Golaszewski Subject: Re: [PATCH v4 01/10] string: provide strends() Message-ID: <202511171230.F83EE85D0@keescook> References: <20251112-gpio-shared-v4-0-b51f97b1abd8@linaro.org> <20251112-gpio-shared-v4-1-b51f97b1abd8@linaro.org> Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251112-gpio-shared-v4-1-b51f97b1abd8@linaro.org> On Wed, Nov 12, 2025 at 02:55:30PM +0100, Bartosz Golaszewski wrote: > From: Bartosz Golaszewski > > Implement a function for checking if a string ends with a different > string and add its kunit test cases. > > Acked-by: Linus Walleij > Signed-off-by: Bartosz Golaszewski > --- > include/linux/string.h | 18 ++++++++++++++++++ > lib/tests/string_kunit.c | 13 +++++++++++++ > 2 files changed, 31 insertions(+) > > diff --git a/include/linux/string.h b/include/linux/string.h > index fdd3442c6bcbd786e177b6e87358e1065a0ffafc..929d05d1247c76eb9011fe34250b487834b2d3c9 100644 > --- a/include/linux/string.h > +++ b/include/linux/string.h > @@ -562,4 +562,22 @@ static inline bool strstarts(const char *str, const char *prefix) > return strncmp(str, prefix, strlen(prefix)) == 0; > } > > +/** > + * strends - Check if a string ends with another string. > + * @str - NULL-terminated string to check against @suffix > + * @suffix - NULL-terminated string defining the suffix to look for in @str > + * > + * Returns: > + * True if @str ends with @suffix. False in all other cases. Maybe added "empty strings never match"? > + */ > +static inline bool strends(const char *str, const char *suffix) These are required to be non-NULL, so we might want to consider marking them as such with the "nonnull" attribute. We don't use it much in Linux yet, but I do see a few places. e.g.: static inline bool __attribute__((nonnull(1,2))) strends(const char *str, const char *suffix) > +{ > + unsigned int str_len = strlen(str), suffix_len = strlen(suffix); > + > + if (str_len < suffix_len) > + return false; > + > + return !(strcmp(str + str_len - suffix_len, suffix)); > +} We should probably add it to strlen and strcmp as well. :) > + > #endif /* _LINUX_STRING_H_ */ > diff --git a/lib/tests/string_kunit.c b/lib/tests/string_kunit.c > index 0ed7448a26d3aa0fe9e2a6a894d4c49c2c0b86e0..f9a8e557ba7734c9848d58ff986407d8000f52ee 100644 > --- a/lib/tests/string_kunit.c > +++ b/lib/tests/string_kunit.c > @@ -602,6 +602,18 @@ static void string_test_memtostr(struct kunit *test) > KUNIT_EXPECT_EQ(test, dest[7], '\0'); > } > > +static void string_test_strends(struct kunit *test) > +{ > + KUNIT_EXPECT_TRUE(test, strends("foo-bar", "bar")); > + KUNIT_EXPECT_TRUE(test, strends("foo-bar", "-bar")); > + KUNIT_EXPECT_TRUE(test, strends("foobar", "foobar")); > + KUNIT_EXPECT_TRUE(test, strends("foobar", "")); > + KUNIT_EXPECT_FALSE(test, strends("bar", "foobar")); > + KUNIT_EXPECT_FALSE(test, strends("", "foo")); > + KUNIT_EXPECT_FALSE(test, strends("foobar", "ba")); > + KUNIT_EXPECT_TRUE(test, strends("", "")); > +} Thanks for adding tests! :) > + > static struct kunit_case string_test_cases[] = { > KUNIT_CASE(string_test_memset16), > KUNIT_CASE(string_test_memset32), > @@ -623,6 +635,7 @@ static struct kunit_case string_test_cases[] = { > KUNIT_CASE(string_test_strlcat), > KUNIT_CASE(string_test_strtomem), > KUNIT_CASE(string_test_memtostr), > + KUNIT_CASE(string_test_strends), > {} > }; > > > -- > 2.51.0 > Reviewed-by: Kees Cook -- Kees Cook