From: Stas Sergeev <stsp@list.ru>
To: stsp@list.ru
Cc: Shuah Khan <shuahkh@osg.samsung.com>,
linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
Andy Lutomirski <luto@amacapital.net>,
Ingo Molnar <mingo@kernel.org>, Oleg Nesterov <oleg@redhat.com>
Subject: [PATCH 4/4] selftests: Add test for sigaltstack(SS_ONSTACK|SS_AUTODISARM)
Date: Thu, 14 Apr 2016 23:20:05 +0300 [thread overview]
Message-ID: <1460665206-13646-5-git-send-email-stsp@list.ru> (raw)
In-Reply-To: <1460665206-13646-1-git-send-email-stsp@list.ru>
This patch adds the test case for SS_AUTODISARM flag.
The test-case tries to set SS_AUTODISARM flag and checks if
the nested signal corrupts the stack after swapcontext().
CC: Shuah Khan <shuahkh@osg.samsung.com>
CC: linux-kernel@vger.kernel.org
CC: linux-api@vger.kernel.org
CC: Andy Lutomirski <luto@amacapital.net>
CC: Ingo Molnar <mingo@kernel.org>
CC: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Stas Sergeev <stsp@list.ru>
---
tools/testing/selftests/Makefile | 1 +
tools/testing/selftests/sigaltstack/Makefile | 8 ++
tools/testing/selftests/sigaltstack/sas.c | 156 +++++++++++++++++++++++++++
3 files changed, 165 insertions(+)
create mode 100644 tools/testing/selftests/sigaltstack/Makefile
create mode 100644 tools/testing/selftests/sigaltstack/sas.c
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index b04afc3..ff9e5f2 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -19,6 +19,7 @@ TARGETS += powerpc
TARGETS += pstore
TARGETS += ptrace
TARGETS += seccomp
+TARGETS += sigaltstack
TARGETS += size
TARGETS += static_keys
TARGETS += sysctl
diff --git a/tools/testing/selftests/sigaltstack/Makefile b/tools/testing/selftests/sigaltstack/Makefile
new file mode 100644
index 0000000..56af56e
--- /dev/null
+++ b/tools/testing/selftests/sigaltstack/Makefile
@@ -0,0 +1,8 @@
+CFLAGS = -Wall
+BINARIES = sas
+all: $(BINARIES)
+
+include ../lib.mk
+
+clean:
+ rm -rf $(BINARIES)
diff --git a/tools/testing/selftests/sigaltstack/sas.c b/tools/testing/selftests/sigaltstack/sas.c
new file mode 100644
index 0000000..57da8bf
--- /dev/null
+++ b/tools/testing/selftests/sigaltstack/sas.c
@@ -0,0 +1,156 @@
+/*
+ * Stas Sergeev <stsp@users.sourceforge.net>
+ *
+ * test sigaltstack(SS_ONSTACK | SS_AUTODISARM)
+ * If that succeeds, then swapcontext() can be used inside sighandler safely.
+ *
+ */
+
+#define _GNU_SOURCE
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/mman.h>
+#include <ucontext.h>
+#include <alloca.h>
+#include <string.h>
+#include <assert.h>
+
+#ifndef SS_AUTODISARM
+#define SS_AUTODISARM (1 << 4)
+#endif
+
+static void *sstack, *ustack;
+static ucontext_t uc, sc;
+static const char *msg = "[OK]\tStack preserved";
+static const char *msg2 = "[FAIL]\tStack corrupted";
+struct stk_data {
+ char msg[128];
+ int flag;
+};
+
+void my_usr1(int sig, siginfo_t *si, void *u)
+{
+ char *aa;
+ int err;
+ stack_t stk;
+ struct stk_data *p;
+
+ register unsigned long sp asm("sp");
+
+ if (sp < (unsigned long)sstack ||
+ sp >= (unsigned long)sstack + SIGSTKSZ) {
+ printf("[FAIL]\tSP is not on sigaltstack\n");
+ exit(EXIT_FAILURE);
+ }
+ /* put some data on stack. other sighandler will try to overwrite it */
+ aa = alloca(1024);
+ assert(aa);
+ p = (struct stk_data *)(aa + 512);
+ strcpy(p->msg, msg);
+ p->flag = 1;
+ printf("[RUN]\tsignal USR1\n");
+ err = sigaltstack(NULL, &stk);
+ if (err) {
+ perror("[FAIL]\tsigaltstack()");
+ exit(EXIT_FAILURE);
+ }
+ if (stk.ss_flags != SS_DISABLE)
+ printf("[FAIL]\tss_flags=%i, should be SS_DISABLE\n",
+ stk.ss_flags);
+ else
+ printf("[OK]\tsigaltstack is disabled in sighandler\n");
+ swapcontext(&sc, &uc);
+ printf("%s\n", p->msg);
+ if (!p->flag) {
+ printf("[RUN]\tAborting\n");
+ exit(EXIT_FAILURE);
+ }
+}
+
+void my_usr2(int sig, siginfo_t *si, void *u)
+{
+ char *aa;
+ struct stk_data *p;
+
+ printf("[RUN]\tsignal USR2\n");
+ aa = alloca(1024);
+ /* dont run valgrind on this */
+ /* try to find the data stored by previous sighandler */
+ p = memmem(aa, 1024, msg, strlen(msg));
+ if (p) {
+ printf("[FAIL]\tsigaltstack re-used\n");
+ /* corrupt the data */
+ strcpy(p->msg, msg2);
+ /* tell other sighandler that his data is corrupted */
+ p->flag = 0;
+ }
+}
+
+static void switch_fn(void)
+{
+ printf("[RUN]\tswitched to user ctx\n");
+ raise(SIGUSR2);
+ setcontext(&sc);
+}
+
+int main(void)
+{
+ struct sigaction act;
+ stack_t stk;
+ int err;
+
+ sigemptyset(&act.sa_mask);
+ act.sa_flags = SA_ONSTACK | SA_SIGINFO;
+ act.sa_sigaction = my_usr1;
+ sigaction(SIGUSR1, &act, NULL);
+ act.sa_sigaction = my_usr2;
+ sigaction(SIGUSR2, &act, NULL);
+ sstack = mmap(NULL, SIGSTKSZ, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0);
+ if (sstack == MAP_FAILED) {
+ perror("mmap()");
+ return EXIT_FAILURE;
+ }
+ stk.ss_sp = sstack;
+ stk.ss_size = SIGSTKSZ;
+ stk.ss_flags = SS_ONSTACK | SS_AUTODISARM;
+ err = sigaltstack(&stk, NULL);
+ if (err) {
+ perror("[FAIL]\tsigaltstack(SS_ONSTACK | SS_AUTODISARM)");
+ stk.ss_flags = SS_ONSTACK;
+ }
+ err = sigaltstack(&stk, NULL);
+ if (err) {
+ perror("[FAIL]\tsigaltstack(SS_ONSTACK)");
+ return EXIT_FAILURE;
+ }
+
+ ustack = mmap(NULL, SIGSTKSZ, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0);
+ if (ustack == MAP_FAILED) {
+ perror("mmap()");
+ return EXIT_FAILURE;
+ }
+ getcontext(&uc);
+ uc.uc_link = NULL;
+ uc.uc_stack.ss_sp = ustack;
+ uc.uc_stack.ss_size = SIGSTKSZ;
+ makecontext(&uc, switch_fn, 0);
+ raise(SIGUSR1);
+
+ err = sigaltstack(NULL, &stk);
+ if (err) {
+ perror("[FAIL]\tsigaltstack()");
+ exit(EXIT_FAILURE);
+ }
+ if (stk.ss_flags != 0) {
+ printf("[FAIL]\tss_flags=%i, should be 0\n",
+ stk.ss_flags);
+ exit(EXIT_FAILURE);
+ }
+ printf("[OK]\tsigaltstack is enabled after signal\n");
+
+ printf("[OK]\tTest passed\n");
+ return 0;
+}
--
2.7.2
next prev parent reply other threads:[~2016-04-14 20:20 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-14 20:20 [PATCH v6(resend2) 0/4] make sigaltstack compatible with swapcontext() Stas Sergeev
2016-04-14 20:20 ` [PATCH 1/4] [Cleanup] x86: signal: unify the sigaltstack check with other arches Stas Sergeev
2016-05-03 7:49 ` [tip:core/signals] signals/sigaltstack, x86/signals: Unify the x86 sigaltstack check with other architectures tip-bot for Stas Sergeev
2016-05-03 16:12 ` Andy Lutomirski
2016-04-14 20:20 ` [PATCH 2/4] sigaltstack: preparations for adding new SS_xxx flags Stas Sergeev
2016-05-03 7:50 ` [tip:core/signals] signals/sigaltstack: Prepare to add " tip-bot for Stas Sergeev
2016-05-03 9:59 ` Borislav Petkov
2016-05-03 16:13 ` Andy Lutomirski
2016-05-03 16:44 ` Andy Lutomirski
2016-04-14 20:20 ` [PATCH 3/4] sigaltstack: implement SS_AUTODISARM flag Stas Sergeev
2016-05-03 7:50 ` [tip:core/signals] signals/sigaltstack: Implement " tip-bot for Stas Sergeev
2016-05-03 16:27 ` Andy Lutomirski
2016-04-14 20:20 ` Stas Sergeev [this message]
2016-05-03 7:50 ` [tip:core/signals] selftests/sigaltstack: Add new testcase for sigaltstack(SS_ONSTACK|SS_AUTODISARM) tip-bot for Stas Sergeev
2016-05-03 16:43 ` Andy Lutomirski
-- strict thread matches above, loose matches on Subject: below --
2016-04-09 12:42 [PATCH v6(RESEND) 0/4] make sigaltstack() compatible with swapcontext() Stas Sergeev
2016-04-09 12:42 ` [PATCH 4/4] selftests: Add test for sigaltstack(SS_ONSTACK|SS_AUTODISARM) Stas Sergeev
2016-03-07 16:52 [PATCH v6 0/4] make sigaltstack() compatible with swapcontext() Stas Sergeev
2016-03-07 16:52 ` [PATCH 4/4] selftests: Add test for sigaltstack(SS_ONSTACK|SS_AUTODISARM) Stas Sergeev
2016-03-07 16:39 [PATCH v5 0/4] make sigaltstack() compatible with swapcontext() Stas Sergeev
2016-03-07 16:39 ` [PATCH 4/4] selftests: Add test for sigaltstack(SS_ONSTACK | SS_AUTODISARM) Stas Sergeev
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