From nobody Tue Nov 26 14:39:12 2024 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.7]) (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 D726F17C21C; Fri, 18 Oct 2024 02:22:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.7 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729218162; cv=none; b=KQUyW1tNdNuIpHQOpVRTYHh1cbnkwS02DwFCZvkCLYWfnNnn4KQUfPswGrbXpybo0qRflAu/wbOyMwlbXAaHww7dVBL5909MZlgqfg1leTiBBsvA61tVu2SIxkGv0ga8sjuWXCJzbyT5032TTst81KRL/5i1bmcrx05GEW0eZpk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729218162; c=relaxed/simple; bh=cwi+GNrykzBZWK3vNEOThjGdwWrEwDOu0Vqo1PrdesE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=BOBHnxYdBo3Fx8A7TZm8Y2whlJ+x0R03l5CKf+B2s6T+GDdzOdfX19XKQmp4PzYvX8WaHUV0pYexESTjBd9bz1cpuQ7FDLXsrU/KIToGq39kYZD5SKDXQBW5xrtMKUygJkrOxr++OttkOEEYrb1v07CKcA5ORsXxk2rCBBZE0hI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=SzN6YK2f; arc=none smtp.client-ip=192.198.163.7 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="SzN6YK2f" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1729218161; x=1760754161; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=cwi+GNrykzBZWK3vNEOThjGdwWrEwDOu0Vqo1PrdesE=; b=SzN6YK2fdXzbe4i3ME19hPLCkwx8E/pBAiv7JAApWrV83/Mj1Ov6OYCj kZ5s/VHKy7AqZgXFp06MiXrpFkmyuu+DVClMUvw2c+wfVzzkmDffg68my ox2IAkGnqzRb8ztQtKYucKn3zKYPjAhwO10MJOxFE+/LHng4eUIHdtEIN FyGnW5X8GjW22saLXYgSHXNJYDAEeHRPRvhlQl3YF26IFkxQzeTemCwg9 9m2HWWQyMl/TZQhi+YXH2wlr1iDxzNO5oV+ZftK5UnnmikbSJs6hr31RU /crl/oCWwz8xPdrUqfjFExK5P724NzTb63cQHqNLviSPgH+Zw4dt7eraq w==; X-CSE-ConnectionGUID: 9nj3zLboQ8+LigpJGcbzPQ== X-CSE-MsgGUID: rfJlyb+LTOa0g93RF+Xbcg== X-IronPort-AV: E=McAfee;i="6700,10204,11228"; a="54149695" X-IronPort-AV: E=Sophos;i="6.11,212,1725346800"; d="scan'208";a="54149695" Received: from orviesa010.jf.intel.com ([10.64.159.150]) by fmvoesa101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Oct 2024 19:22:37 -0700 X-CSE-ConnectionGUID: SdtlWhQlRLuka4srtVWbjA== X-CSE-MsgGUID: Fc/YGfGdRPCg4lu9BTXX8g== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.11,212,1725346800"; d="scan'208";a="78697711" Received: from rchatre-desk1.jf.intel.com ([10.165.154.99]) by orviesa010-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Oct 2024 19:22:36 -0700 From: Reinette Chatre To: fenghua.yu@intel.com, shuah@kernel.org, tony.luck@intel.com, peternewman@google.com, babu.moger@amd.com, ilpo.jarvinen@linux.intel.com Cc: maciej.wieczor-retman@intel.com, reinette.chatre@intel.com, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH V3 05/15] selftests/resctrl: Protect against array overflow when reading strings Date: Thu, 17 Oct 2024 19:33:20 -0700 Message-ID: <4adf01b3ee7019163ea4fc00b5d03d514d41b4b7.1729218182.git.reinette.chatre@intel.com> X-Mailer: git-send-email 2.46.2 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" resctrl selftests discover system properties via a variety of sysfs files. The MBM and MBA tests need to discover the event and umask with which to configure the performance event used to measure read memory bandwidth. This is done by parsing the contents of /sys/bus/event_source/devices/uncore_imc_/events/cas_count_re= ad Similarly, the resctrl selftests discover the cache size via /sys/bus/cpu/devices/cpu/cache/index/size. Take care to do bounds checking when using fscanf() to read the contents of files into a string buffer because by default fscanf() assumes arbitrarily long strings. If the file contains more bytes than the array can accommodate then an overflow will occur. Provide a maximum field width to the conversion specifier to protect against array overflow. The maximum is one less than the array size because string input stores a terminating null byte that is not covered by the maximum field width. Signed-off-by: Reinette Chatre Reviewed-by: Ilpo J=C3=A4rvinen --- This makes the code robust against any changes in information read from sysfs. The existing sysfs content fit well into the arrays, thus this is not considered a bugfix. Changes since V2: - New patch --- tools/testing/selftests/resctrl/resctrl_val.c | 4 ++-- tools/testing/selftests/resctrl/resctrlfs.c | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/resctrl/resctrl_val.c b/tools/testing/= selftests/resctrl/resctrl_val.c index e88d5ca30517..c9dd70ce3ea8 100644 --- a/tools/testing/selftests/resctrl/resctrl_val.c +++ b/tools/testing/selftests/resctrl/resctrl_val.c @@ -159,7 +159,7 @@ static int read_from_imc_dir(char *imc_dir, int count) =20 return -1; } - if (fscanf(fp, "%s", cas_count_cfg) <=3D 0) { + if (fscanf(fp, "%1023s", cas_count_cfg) <=3D 0) { ksft_perror("Could not get iMC cas count read"); fclose(fp); =20 @@ -177,7 +177,7 @@ static int read_from_imc_dir(char *imc_dir, int count) =20 return -1; } - if (fscanf(fp, "%s", cas_count_cfg) <=3D 0) { + if (fscanf(fp, "%1023s", cas_count_cfg) <=3D 0) { ksft_perror("Could not get iMC cas count write"); fclose(fp); =20 diff --git a/tools/testing/selftests/resctrl/resctrlfs.c b/tools/testing/se= lftests/resctrl/resctrlfs.c index 250c320349a7..a53cd1cb6e0c 100644 --- a/tools/testing/selftests/resctrl/resctrlfs.c +++ b/tools/testing/selftests/resctrl/resctrlfs.c @@ -182,7 +182,7 @@ int get_cache_size(int cpu_no, const char *cache_type, = unsigned long *cache_size =20 return -1; } - if (fscanf(fp, "%s", cache_str) <=3D 0) { + if (fscanf(fp, "%63s", cache_str) <=3D 0) { ksft_perror("Could not get cache_size"); fclose(fp); =20 --=20 2.46.2