From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:42514 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936138AbeBUNIj (ORCPT ); Wed, 21 Feb 2018 08:08:39 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ingo Molnar , Dominik Brodowski , Andrew Lutomirski , Linus Torvalds , Peter Zijlstra , Thomas Gleixner , linux-kselftest@vger.kernel.org, shuah@kernel.org Subject: [PATCH 4.15 069/163] selftests/x86: Clean up and document sscanf() usage Date: Wed, 21 Feb 2018 13:48:18 +0100 Message-Id: <20180221124534.300516334@linuxfoundation.org> In-Reply-To: <20180221124529.931834518@linuxfoundation.org> References: <20180221124529.931834518@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dominik Brodowski commit d8e92de8ef952bed88c56c7a44c02d8dcae0984e upstream. Replace a couple of magically connected buffer length literal constants with a common definition that makes their relationship obvious. Also document why our sscanf() usage is safe. No intended functional changes. Suggested-by: Ingo Molnar Signed-off-by: Dominik Brodowski Cc: Andrew Lutomirski Cc: Andy Lutomirski Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kselftest@vger.kernel.org Cc: shuah@kernel.org Link: http://lkml.kernel.org/r/20180211205924.GA23210@light.dominikbrodowski.net Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- tools/testing/selftests/x86/test_vdso.c | 11 ++++++++--- tools/testing/selftests/x86/test_vsyscall.c | 11 ++++++++--- 2 files changed, 16 insertions(+), 6 deletions(-) --- a/tools/testing/selftests/x86/test_vdso.c +++ b/tools/testing/selftests/x86/test_vdso.c @@ -26,6 +26,9 @@ # endif #endif +/* max length of lines in /proc/self/maps - anything longer is skipped here */ +#define MAPS_LINE_LEN 128 + int nerrs = 0; typedef long (*getcpu_t)(unsigned *, unsigned *, void *); @@ -37,17 +40,19 @@ static void *vsyscall_getcpu(void) { #ifdef __x86_64__ FILE *maps; - char line[128]; + char line[MAPS_LINE_LEN]; bool found = false; maps = fopen("/proc/self/maps", "r"); if (!maps) /* might still be present, but ignore it here, as we test vDSO not vsyscall */ return NULL; - while (fgets(line, sizeof(line), maps)) { + while (fgets(line, MAPS_LINE_LEN, maps)) { char r, x; void *start, *end; - char name[128]; + char name[MAPS_LINE_LEN]; + + /* sscanf() is safe here as strlen(name) >= strlen(line) */ if (sscanf(line, "%p-%p %c-%cp %*x %*x:%*x %*u %s", &start, &end, &r, &x, name) != 5) continue; --- a/tools/testing/selftests/x86/test_vsyscall.c +++ b/tools/testing/selftests/x86/test_vsyscall.c @@ -33,6 +33,9 @@ # endif #endif +/* max length of lines in /proc/self/maps - anything longer is skipped here */ +#define MAPS_LINE_LEN 128 + static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *), int flags) { @@ -98,7 +101,7 @@ static int init_vsys(void) #ifdef __x86_64__ int nerrs = 0; FILE *maps; - char line[128]; + char line[MAPS_LINE_LEN]; bool found = false; maps = fopen("/proc/self/maps", "r"); @@ -108,10 +111,12 @@ static int init_vsys(void) return 0; } - while (fgets(line, sizeof(line), maps)) { + while (fgets(line, MAPS_LINE_LEN, maps)) { char r, x; void *start, *end; - char name[128]; + char name[MAPS_LINE_LEN]; + + /* sscanf() is safe here as strlen(name) >= strlen(line) */ if (sscanf(line, "%p-%p %c-%cp %*x %*x:%*x %*u %s", &start, &end, &r, &x, name) != 5) continue;