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Message-Id: <20200705061232.4151319-3-keescook@chromium.org>
Date: Sat, 4 Jul 2020 23:12:31 -0700
From: Kees Cook <keescook@...omium.org>
To: Will Deacon <will@...nel.org>
Cc: Kees Cook <keescook@...omium.org>,
Andy Lutomirski <luto@...capital.net>,
Will Drewry <wad@...omium.org>,
Jakub Kicinski <kuba@...nel.org>,
Keno Fischer <keno@...iacomputing.com>,
Oleg Nesterov <oleg@...hat.com>, Shuah Khan <shuah@...nel.org>,
linux-kselftest@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 2/3] selftests/seccomp: Refactor to use fixture variants
Now that the selftest harness has variants, use them to eliminate a
bunch of copy/paste duplication.
Cc: Andy Lutomirski <luto@...capital.net>
Cc: Will Drewry <wad@...omium.org>
Cc: Jakub Kicinski <kuba@...nel.org>
Signed-off-by: Kees Cook <keescook@...omium.org>
---
tools/testing/selftests/seccomp/seccomp_bpf.c | 199 ++++--------------
1 file changed, 42 insertions(+), 157 deletions(-)
diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
index 6439c031a85d..966dec340ea8 100644
--- a/tools/testing/selftests/seccomp/seccomp_bpf.c
+++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
@@ -1541,6 +1541,7 @@ pid_t setup_trace_fixture(struct __test_metadata *_metadata,
return tracer_pid;
}
+
void teardown_trace_fixture(struct __test_metadata *_metadata,
pid_t tracer)
{
@@ -1820,7 +1821,7 @@ void change_syscall(struct __test_metadata *_metadata,
EXPECT_EQ(0, ret);
}
-void tracer_syscall(struct __test_metadata *_metadata, pid_t tracee,
+void tracer_seccomp(struct __test_metadata *_metadata, pid_t tracee,
int status, void *args)
{
int ret;
@@ -1897,6 +1898,24 @@ FIXTURE(TRACE_syscall) {
pid_t tracer, mytid, mypid, parent;
};
+FIXTURE_VARIANT(TRACE_syscall) {
+ /*
+ * All of the SECCOMP_RET_TRACE behaviors can be tested with either
+ * SECCOMP_RET_TRACE+PTRACE_CONT or plain ptrace()+PTRACE_SYSCALL.
+ * This indicates if we should use SECCOMP_RET_TRACE (false), or
+ * ptrace (true).
+ */
+ bool use_ptrace;
+};
+
+FIXTURE_VARIANT_ADD(TRACE_syscall, ptrace) {
+ .use_ptrace = true,
+};
+
+FIXTURE_VARIANT_ADD(TRACE_syscall, seccomp) {
+ .use_ptrace = false,
+};
+
FIXTURE_SETUP(TRACE_syscall)
{
struct sock_filter filter[] = {
@@ -1912,12 +1931,11 @@ FIXTURE_SETUP(TRACE_syscall)
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE | 0x1005),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
-
- memset(&self->prog, 0, sizeof(self->prog));
- self->prog.filter = malloc(sizeof(filter));
- ASSERT_NE(NULL, self->prog.filter);
- memcpy(self->prog.filter, filter, sizeof(filter));
- self->prog.len = (unsigned short)ARRAY_SIZE(filter);
+ struct sock_fprog prog = {
+ .len = (unsigned short)ARRAY_SIZE(filter),
+ .filter = filter,
+ };
+ long ret;
/* Prepare some testable syscall results. */
self->mytid = syscall(__NR_gettid);
@@ -1935,60 +1953,28 @@ FIXTURE_SETUP(TRACE_syscall)
ASSERT_NE(self->parent, self->mypid);
/* Launch tracer. */
- self->tracer = setup_trace_fixture(_metadata, tracer_syscall, NULL,
- false);
-}
-
-FIXTURE_TEARDOWN(TRACE_syscall)
-{
- teardown_trace_fixture(_metadata, self->tracer);
- if (self->prog.filter)
- free(self->prog.filter);
-}
+ self->tracer = setup_trace_fixture(_metadata,
+ variant->use_ptrace ? tracer_ptrace
+ : tracer_seccomp,
+ NULL, variant->use_ptrace);
-TEST_F(TRACE_syscall, ptrace_syscall_redirected)
-{
- /* Swap SECCOMP_RET_TRACE tracer for PTRACE_SYSCALL tracer. */
- teardown_trace_fixture(_metadata, self->tracer);
- self->tracer = setup_trace_fixture(_metadata, tracer_ptrace, NULL,
- true);
-
- /* Tracer will redirect getpid to getppid. */
- EXPECT_NE(self->mypid, syscall(__NR_getpid));
-}
+ ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
+ ASSERT_EQ(0, ret);
-TEST_F(TRACE_syscall, ptrace_syscall_errno)
-{
- /* Swap SECCOMP_RET_TRACE tracer for PTRACE_SYSCALL tracer. */
- teardown_trace_fixture(_metadata, self->tracer);
- self->tracer = setup_trace_fixture(_metadata, tracer_ptrace, NULL,
- true);
+ if (variant->use_ptrace)
+ return;
- /* Tracer should skip the open syscall, resulting in ESRCH. */
- EXPECT_SYSCALL_RETURN(-ESRCH, syscall(__NR_openat));
+ ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0);
+ ASSERT_EQ(0, ret);
}
-TEST_F(TRACE_syscall, ptrace_syscall_faked)
+FIXTURE_TEARDOWN(TRACE_syscall)
{
- /* Swap SECCOMP_RET_TRACE tracer for PTRACE_SYSCALL tracer. */
teardown_trace_fixture(_metadata, self->tracer);
- self->tracer = setup_trace_fixture(_metadata, tracer_ptrace, NULL,
- true);
-
- /* Tracer should skip the gettid syscall, resulting fake pid. */
- EXPECT_SYSCALL_RETURN(45000, syscall(__NR_gettid));
}
TEST_F(TRACE_syscall, syscall_allowed)
{
- long ret;
-
- ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
- ASSERT_EQ(0, ret);
-
- ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0);
- ASSERT_EQ(0, ret);
-
/* getppid works as expected (no changes). */
EXPECT_EQ(self->parent, syscall(__NR_getppid));
EXPECT_NE(self->mypid, syscall(__NR_getppid));
@@ -1996,14 +1982,6 @@ TEST_F(TRACE_syscall, syscall_allowed)
TEST_F(TRACE_syscall, syscall_redirected)
{
- long ret;
-
- ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
- ASSERT_EQ(0, ret);
-
- ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0);
- ASSERT_EQ(0, ret);
-
/* getpid has been redirected to getppid as expected. */
EXPECT_EQ(self->parent, syscall(__NR_getpid));
EXPECT_NE(self->mypid, syscall(__NR_getpid));
@@ -2011,33 +1989,17 @@ TEST_F(TRACE_syscall, syscall_redirected)
TEST_F(TRACE_syscall, syscall_errno)
{
- long ret;
-
- ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
- ASSERT_EQ(0, ret);
-
- ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0);
- ASSERT_EQ(0, ret);
-
- /* openat has been skipped and an errno return. */
+ /* Tracer should skip the open syscall, resulting in ESRCH. */
EXPECT_SYSCALL_RETURN(-ESRCH, syscall(__NR_openat));
}
TEST_F(TRACE_syscall, syscall_faked)
{
- long ret;
-
- ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
- ASSERT_EQ(0, ret);
-
- ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0);
- ASSERT_EQ(0, ret);
-
- /* gettid has been skipped and an altered return value stored. */
+ /* Tracer skips the gettid syscall and store altered return value. */
EXPECT_SYSCALL_RETURN(45000, syscall(__NR_gettid));
}
-TEST_F(TRACE_syscall, skip_after_RET_TRACE)
+TEST_F(TRACE_syscall, skip_after)
{
struct sock_filter filter[] = {
BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
@@ -2052,14 +2014,7 @@ TEST_F(TRACE_syscall, skip_after_RET_TRACE)
};
long ret;
- ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
- ASSERT_EQ(0, ret);
-
- /* Install fixture filter. */
- ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0);
- ASSERT_EQ(0, ret);
-
- /* Install "errno on getppid" filter. */
+ /* Install additional "errno on getppid" filter. */
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0);
ASSERT_EQ(0, ret);
@@ -2069,7 +2024,7 @@ TEST_F(TRACE_syscall, skip_after_RET_TRACE)
EXPECT_EQ(EPERM, errno);
}
-TEST_F_SIGNAL(TRACE_syscall, kill_after_RET_TRACE, SIGSYS)
+TEST_F_SIGNAL(TRACE_syscall, kill_after, SIGSYS)
{
struct sock_filter filter[] = {
BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
@@ -2084,77 +2039,7 @@ TEST_F_SIGNAL(TRACE_syscall, kill_after_RET_TRACE, SIGSYS)
};
long ret;
- ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
- ASSERT_EQ(0, ret);
-
- /* Install fixture filter. */
- ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0);
- ASSERT_EQ(0, ret);
-
- /* Install "death on getppid" filter. */
- ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0);
- ASSERT_EQ(0, ret);
-
- /* Tracer will redirect getpid to getppid, and we should die. */
- EXPECT_NE(self->mypid, syscall(__NR_getpid));
-}
-
-TEST_F(TRACE_syscall, skip_after_ptrace)
-{
- struct sock_filter filter[] = {
- BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
- offsetof(struct seccomp_data, nr)),
- BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getppid, 0, 1),
- BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ERRNO | EPERM),
- BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
- };
- struct sock_fprog prog = {
- .len = (unsigned short)ARRAY_SIZE(filter),
- .filter = filter,
- };
- long ret;
-
- /* Swap SECCOMP_RET_TRACE tracer for PTRACE_SYSCALL tracer. */
- teardown_trace_fixture(_metadata, self->tracer);
- self->tracer = setup_trace_fixture(_metadata, tracer_ptrace, NULL,
- true);
-
- ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
- ASSERT_EQ(0, ret);
-
- /* Install "errno on getppid" filter. */
- ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0);
- ASSERT_EQ(0, ret);
-
- /* Tracer will redirect getpid to getppid, and we should see EPERM. */
- EXPECT_EQ(-1, syscall(__NR_getpid));
- EXPECT_EQ(EPERM, errno);
-}
-
-TEST_F_SIGNAL(TRACE_syscall, kill_after_ptrace, SIGSYS)
-{
- struct sock_filter filter[] = {
- BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
- offsetof(struct seccomp_data, nr)),
- BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getppid, 0, 1),
- BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL),
- BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
- };
- struct sock_fprog prog = {
- .len = (unsigned short)ARRAY_SIZE(filter),
- .filter = filter,
- };
- long ret;
-
- /* Swap SECCOMP_RET_TRACE tracer for PTRACE_SYSCALL tracer. */
- teardown_trace_fixture(_metadata, self->tracer);
- self->tracer = setup_trace_fixture(_metadata, tracer_ptrace, NULL,
- true);
-
- ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
- ASSERT_EQ(0, ret);
-
- /* Install "death on getppid" filter. */
+ /* Install additional "death on getppid" filter. */
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0);
ASSERT_EQ(0, ret);
--
2.25.1
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