[PATCH v3 1/1] selftests/landlock: skip ptrace_test according to YAMA
jeffxu at chromium.org
jeffxu at chromium.org
Tue Dec 27 14:02:44 UTC 2022
From: Jeff Xu <jeffxu at google.com>
Add check for yama setting for ptrace_test.
Signed-off-by: Jeff Xu <jeffxu at google.com>
---
.../testing/selftests/landlock/ptrace_test.c | 173 ++++++++++++------
1 file changed, 112 insertions(+), 61 deletions(-)
diff --git a/tools/testing/selftests/landlock/ptrace_test.c b/tools/testing/selftests/landlock/ptrace_test.c
index c28ef98ff3ac..0056815deef8 100644
--- a/tools/testing/selftests/landlock/ptrace_test.c
+++ b/tools/testing/selftests/landlock/ptrace_test.c
@@ -60,6 +60,23 @@ static int test_ptrace_read(const pid_t pid)
return 0;
}
+static int get_yama_ptrace_scope(void)
+{
+ int ret = -1;
+ char buf[2] = {};
+ int fd = open("/proc/sys/kernel/yama/ptrace_scope", O_RDONLY);
+
+ if (fd < 0)
+ return 0;
+
+ if (read(fd, &buf, 1) < 0)
+ return -1;
+
+ ret = atoi(buf);
+ close(fd);
+ return ret;
+}
+
/* clang-format off */
FIXTURE(hierarchy) {};
/* clang-format on */
@@ -69,6 +86,7 @@ FIXTURE_VARIANT(hierarchy)
const bool domain_both;
const bool domain_parent;
const bool domain_child;
+ const int yama_ptrace_scope_max_supported;
};
/*
@@ -93,6 +111,7 @@ FIXTURE_VARIANT_ADD(hierarchy, allow_without_domain) {
.domain_both = false,
.domain_parent = false,
.domain_child = false,
+ .yama_ptrace_scope_max_supported = 0,
};
/*
@@ -110,6 +129,7 @@ FIXTURE_VARIANT_ADD(hierarchy, allow_with_one_domain) {
.domain_both = false,
.domain_parent = false,
.domain_child = true,
+ .yama_ptrace_scope_max_supported = 1,
};
/*
@@ -126,6 +146,7 @@ FIXTURE_VARIANT_ADD(hierarchy, deny_with_parent_domain) {
.domain_both = false,
.domain_parent = true,
.domain_child = false,
+ .yama_ptrace_scope_max_supported = 0,
};
/*
@@ -143,6 +164,7 @@ FIXTURE_VARIANT_ADD(hierarchy, deny_with_sibling_domain) {
.domain_both = false,
.domain_parent = true,
.domain_child = true,
+ .yama_ptrace_scope_max_supported = 2,
};
/*
@@ -160,6 +182,7 @@ FIXTURE_VARIANT_ADD(hierarchy, allow_sibling_domain) {
.domain_both = true,
.domain_parent = false,
.domain_child = false,
+ .yama_ptrace_scope_max_supported = 0,
};
/*
@@ -178,6 +201,7 @@ FIXTURE_VARIANT_ADD(hierarchy, allow_with_nested_domain) {
.domain_both = true,
.domain_parent = false,
.domain_child = true,
+ .yama_ptrace_scope_max_supported = 1,
};
/*
@@ -196,6 +220,7 @@ FIXTURE_VARIANT_ADD(hierarchy, deny_with_nested_and_parent_domain) {
.domain_both = true,
.domain_parent = true,
.domain_child = false,
+ .yama_ptrace_scope_max_supported = 0,
};
/*
@@ -216,6 +241,7 @@ FIXTURE_VARIANT_ADD(hierarchy, deny_with_forked_domain) {
.domain_both = true,
.domain_parent = true,
.domain_child = true,
+ .yama_ptrace_scope_max_supported = 2,
};
FIXTURE_SETUP(hierarchy)
@@ -232,8 +258,20 @@ TEST_F(hierarchy, trace)
pid_t child, parent;
int status, err_proc_read;
int pipe_child[2], pipe_parent[2];
+ int yama_ptrace_scope;
char buf_parent;
long ret;
+ bool can_trace_child, can_trace_parent;
+
+ yama_ptrace_scope = get_yama_ptrace_scope();
+ ASSERT_LE(0, yama_ptrace_scope);
+
+ if (yama_ptrace_scope >= 3)
+ SKIP(return, "Yama forbids any ptrace use (scope %d)", yama_ptrace_scope);
+
+ can_trace_child = !variant->domain_parent && (yama_ptrace_scope < 2);
+ can_trace_parent = !variant->domain_child && (yama_ptrace_scope < 1);
+ TH_LOG("can_trace_child:%d, can_trace_parent:%d", can_trace_child, can_trace_parent);
/*
* Removes all effective and permitted capabilities to not interfere
@@ -258,6 +296,7 @@ TEST_F(hierarchy, trace)
ASSERT_EQ(0, close(pipe_parent[1]));
ASSERT_EQ(0, close(pipe_child[0]));
+
if (variant->domain_child)
create_domain(_metadata);
@@ -265,43 +304,47 @@ TEST_F(hierarchy, trace)
ASSERT_EQ(1, read(pipe_parent[0], &buf_child, 1));
/* Tests PTRACE_ATTACH and PTRACE_MODE_READ on the parent. */
- err_proc_read = test_ptrace_read(parent);
- ret = ptrace(PTRACE_ATTACH, parent, NULL, 0);
- if (variant->domain_child) {
- EXPECT_EQ(-1, ret);
- EXPECT_EQ(EPERM, errno);
- EXPECT_EQ(EACCES, err_proc_read);
- } else {
- EXPECT_EQ(0, ret);
- EXPECT_EQ(0, err_proc_read);
- }
- if (ret == 0) {
- ASSERT_EQ(parent, waitpid(parent, &status, 0));
- ASSERT_EQ(1, WIFSTOPPED(status));
- ASSERT_EQ(0, ptrace(PTRACE_DETACH, parent, NULL, 0));
+ if (can_trace_parent) {
+ err_proc_read = test_ptrace_read(parent);
+ ret = ptrace(PTRACE_ATTACH, parent, NULL, 0);
+ if (variant->domain_child) {
+ EXPECT_EQ(-1, ret);
+ EXPECT_EQ(EPERM, errno);
+ EXPECT_EQ(EACCES, err_proc_read);
+ } else {
+ EXPECT_EQ(0, ret);
+ EXPECT_EQ(0, err_proc_read);
+ }
+ if (ret == 0) {
+ ASSERT_EQ(parent, waitpid(parent, &status, 0));
+ ASSERT_EQ(1, WIFSTOPPED(status));
+ ASSERT_EQ(0, ptrace(PTRACE_DETACH, parent, NULL, 0));
+ }
}
/* Tests child PTRACE_TRACEME. */
- ret = ptrace(PTRACE_TRACEME);
- if (variant->domain_parent) {
- EXPECT_EQ(-1, ret);
- EXPECT_EQ(EPERM, errno);
- } else {
- EXPECT_EQ(0, ret);
+ if (can_trace_child) {
+ ret = ptrace(PTRACE_TRACEME);
+ if (variant->domain_parent) {
+ EXPECT_EQ(-1, ret);
+ EXPECT_EQ(EPERM, errno);
+ } else {
+ EXPECT_EQ(0, ret);
+ }
+
+ /*
+ * Signals that the PTRACE_ATTACH test is done and the
+ * PTRACE_TRACEME test is ongoing.
+ */
+ ASSERT_EQ(1, write(pipe_child[1], ".", 1));
+
+ if (!variant->domain_parent)
+ ASSERT_EQ(0, raise(SIGSTOP));
+
+ /* Waits for the parent PTRACE_ATTACH test. */
+ ASSERT_EQ(1, read(pipe_parent[0], &buf_child, 1));
}
- /*
- * Signals that the PTRACE_ATTACH test is done and the
- * PTRACE_TRACEME test is ongoing.
- */
- ASSERT_EQ(1, write(pipe_child[1], ".", 1));
-
- if (!variant->domain_parent) {
- ASSERT_EQ(0, raise(SIGSTOP));
- }
-
- /* Waits for the parent PTRACE_ATTACH test. */
- ASSERT_EQ(1, read(pipe_parent[0], &buf_child, 1));
_exit(_metadata->passed ? EXIT_SUCCESS : EXIT_FAILURE);
return;
}
@@ -318,42 +361,50 @@ TEST_F(hierarchy, trace)
* Waits for the child to test PTRACE_ATTACH on the parent and start
* testing PTRACE_TRACEME.
*/
- ASSERT_EQ(1, read(pipe_child[0], &buf_parent, 1));
-
- /* Tests child PTRACE_TRACEME. */
- if (!variant->domain_parent) {
- ASSERT_EQ(child, waitpid(child, &status, 0));
- ASSERT_EQ(1, WIFSTOPPED(status));
- ASSERT_EQ(0, ptrace(PTRACE_DETACH, child, NULL, 0));
- } else {
- /* The child should not be traced by the parent. */
- EXPECT_EQ(-1, ptrace(PTRACE_DETACH, child, NULL, 0));
- EXPECT_EQ(ESRCH, errno);
- }
+ if (can_trace_child) {
+ ASSERT_EQ(1, read(pipe_child[0], &buf_parent, 1));
- /* Tests PTRACE_ATTACH and PTRACE_MODE_READ on the child. */
- err_proc_read = test_ptrace_read(child);
- ret = ptrace(PTRACE_ATTACH, child, NULL, 0);
- if (variant->domain_parent) {
- EXPECT_EQ(-1, ret);
- EXPECT_EQ(EPERM, errno);
- EXPECT_EQ(EACCES, err_proc_read);
- } else {
- EXPECT_EQ(0, ret);
- EXPECT_EQ(0, err_proc_read);
- }
- if (ret == 0) {
- ASSERT_EQ(child, waitpid(child, &status, 0));
- ASSERT_EQ(1, WIFSTOPPED(status));
- ASSERT_EQ(0, ptrace(PTRACE_DETACH, child, NULL, 0));
+ /* Tests child PTRACE_TRACEME. */
+ if (!variant->domain_parent) {
+ ASSERT_EQ(child, waitpid(child, &status, 0));
+ ASSERT_EQ(1, WIFSTOPPED(status));
+ ASSERT_EQ(0, ptrace(PTRACE_DETACH, child, NULL, 0));
+ } else {
+ /* The child should not be traced by the parent. */
+ EXPECT_EQ(-1, ptrace(PTRACE_DETACH, child, NULL, 0));
+ EXPECT_EQ(ESRCH, errno);
+ }
+
+ /* Tests PTRACE_ATTACH and PTRACE_MODE_READ on the child. */
+ err_proc_read = test_ptrace_read(child);
+ ret = ptrace(PTRACE_ATTACH, child, NULL, 0);
+ if (variant->domain_parent) {
+ EXPECT_EQ(-1, ret);
+ EXPECT_EQ(EPERM, errno);
+ EXPECT_EQ(EACCES, err_proc_read);
+ } else {
+ EXPECT_EQ(0, ret);
+ EXPECT_EQ(0, err_proc_read);
+ }
+ if (ret == 0) {
+ ASSERT_EQ(child, waitpid(child, &status, 0));
+ ASSERT_EQ(1, WIFSTOPPED(status));
+ ASSERT_EQ(0, ptrace(PTRACE_DETACH, child, NULL, 0));
+ }
+
+ /* Signals that the parent PTRACE_ATTACH test is done. */
+ ASSERT_EQ(1, write(pipe_parent[1], ".", 1));
}
- /* Signals that the parent PTRACE_ATTACH test is done. */
- ASSERT_EQ(1, write(pipe_parent[1], ".", 1));
ASSERT_EQ(child, waitpid(child, &status, 0));
if (WIFSIGNALED(status) || !WIFEXITED(status) ||
WEXITSTATUS(status) != EXIT_SUCCESS)
_metadata->passed = 0;
+
+ if (yama_ptrace_scope > 0)
+ SKIP(return, "Incomplete tests due to Yama restrictions (ptrace_scope:%d)",
+ yama_ptrace_scope);
+
}
TEST_HARNESS_MAIN
--
2.39.0.314.g84b9a713c41-goog
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