From: tip-bot for Dominik Brodowski <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: luto@kernel.org, linux@dominikbrodowski.net,
linux-kernel@vger.kernel.org, torvalds@linux-foundation.org,
peterz@infradead.org, hpa@zytor.com, mingo@kernel.org,
tglx@linutronix.de
Subject: [tip:x86/pti] selftests/x86: Clean up and document sscanf() usage
Date: Tue, 13 Feb 2018 01:04:58 -0800 [thread overview]
Message-ID: <tip-d8e92de8ef952bed88c56c7a44c02d8dcae0984e@git.kernel.org> (raw)
In-Reply-To: <20180211205924.GA23210@light.dominikbrodowski.net>
Commit-ID: d8e92de8ef952bed88c56c7a44c02d8dcae0984e
Gitweb: https://git.kernel.org/tip/d8e92de8ef952bed88c56c7a44c02d8dcae0984e
Author: Dominik Brodowski <linux@dominikbrodowski.net>
AuthorDate: Sun, 11 Feb 2018 21:59:24 +0100
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 13 Feb 2018 09:04:56 +0100
selftests/x86: Clean up and document sscanf() usage
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 <mingo@kernel.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Andrew Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
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 <mingo@kernel.org>
---
tools/testing/selftests/x86/test_vdso.c | 11 ++++++++---
tools/testing/selftests/x86/test_vsyscall.c | 11 ++++++++---
2 files changed, 16 insertions(+), 6 deletions(-)
diff --git a/tools/testing/selftests/x86/test_vdso.c b/tools/testing/selftests/x86/test_vdso.c
index 558c820..2352590 100644
--- 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;
diff --git a/tools/testing/selftests/x86/test_vsyscall.c b/tools/testing/selftests/x86/test_vsyscall.c
index 7a744fa..be81621 100644
--- 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;
next prev parent reply other threads:[~2018-02-13 9:05 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-11 11:10 [PATCH 0/5] selftests/x86: fixes for !CONFIG_IA32_EMULATION and vsyscall=none Dominik Brodowski
2018-02-11 11:10 ` [Linux-kselftest-mirror] " Dominik Brodowski
2018-02-11 11:10 ` linux
2018-02-11 11:10 ` [PATCH 1/5] selftests/x86: 5lvl test has been moved Dominik Brodowski
2018-02-11 11:10 ` [Linux-kselftest-mirror] " Dominik Brodowski
2018-02-11 11:10 ` linux
2018-02-11 12:13 ` [tip:x86/urgent] selftests/x86: Fix build bug caused by the 5lvl test which has been moved to the VM directory tip-bot for Dominik Brodowski
2018-02-13 9:05 ` [tip:x86/pti] " tip-bot for Dominik Brodowski
2018-02-11 11:10 ` [PATCH 2/5] selftests/x86: fix vDSO selftest segfault for vsyscall=none Dominik Brodowski
2018-02-11 11:10 ` [Linux-kselftest-mirror] " Dominik Brodowski
2018-02-11 11:10 ` linux
2018-02-11 11:21 ` Ingo Molnar
2018-02-11 11:21 ` [Linux-kselftest-mirror] " Ingo Molnar
2018-02-11 11:21 ` mingo
2018-02-11 12:17 ` Dominik Brodowski
2018-02-11 12:17 ` [Linux-kselftest-mirror] " Dominik Brodowski
2018-02-11 12:17 ` linux
2018-02-11 13:00 ` Dominik Brodowski
2018-02-11 13:00 ` [Linux-kselftest-mirror] " Dominik Brodowski
2018-02-11 13:00 ` linux
2018-02-11 18:24 ` Ingo Molnar
2018-02-11 18:24 ` [Linux-kselftest-mirror] " Ingo Molnar
2018-02-11 18:24 ` mingo
2018-02-11 20:59 ` [PATCH] selftests/x86: clarify that there is no buffer overflow on sscanf usage Dominik Brodowski
2018-02-11 20:59 ` [Linux-kselftest-mirror] " Dominik Brodowski
2018-02-11 20:59 ` linux
2018-02-12 17:58 ` Shuah Khan
2018-02-12 17:58 ` [Linux-kselftest-mirror] " Shuah Khan
2018-02-12 17:58 ` shuah
2018-02-13 9:04 ` tip-bot for Dominik Brodowski [this message]
2018-02-13 9:04 ` [tip:x86/pti] selftests/x86: Fix vDSO selftest segfault for vsyscall=none tip-bot for Dominik Brodowski
2018-02-11 11:10 ` [PATCH 3/5] selftests/x86: do not rely on int $0x80 in test_mremap_vdso.c Dominik Brodowski
2018-02-11 11:10 ` [Linux-kselftest-mirror] " Dominik Brodowski
2018-02-11 11:10 ` linux
2018-02-11 12:13 ` [tip:x86/urgent] selftests/x86: Do not rely on "int $0x80" " tip-bot for Dominik Brodowski
2018-02-13 9:06 ` [tip:x86/pti] " tip-bot for Dominik Brodowski
2018-02-11 11:10 ` [PATCH 4/5] selftests/x86: do not rely on int $0x80 in single_step_syscall.c Dominik Brodowski
2018-02-11 11:10 ` [Linux-kselftest-mirror] " Dominik Brodowski
2018-02-11 11:10 ` linux
2018-02-11 12:14 ` [tip:x86/urgent] selftests/x86: Do not rely on "int $0x80" " tip-bot for Dominik Brodowski
2018-02-13 9:06 ` [tip:x86/pti] " tip-bot for Ingo Molnar
2018-02-15 0:25 ` tip-bot for Dominik Brodowski
2018-02-11 11:10 ` [PATCH 5/5] selftests/x86: disable tests requiring 32bit support on pure 64bit systems Dominik Brodowski
2018-02-11 11:10 ` [Linux-kselftest-mirror] " Dominik Brodowski
2018-02-11 11:10 ` linux
2018-02-11 12:14 ` [tip:x86/urgent] selftests/x86: Disable tests requiring 32-bit support on pure 64-bit systems tip-bot for Dominik Brodowski
2018-02-13 9:07 ` [tip:x86/pti] " tip-bot for Ingo Molnar
2018-02-15 0:25 ` tip-bot for Dominik Brodowski
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