seccomp: add a selftest for get_metadata
Let's test that we get the flags correctly, and that we preserve the filter
index across the ptrace(PTRACE_SECCOMP_GET_METADATA) correctly.
Signed-off-by: Tycho Andersen <tycho@tycho.ws>
CC: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
index 24dbf63..92db488 100644
--- a/tools/testing/selftests/seccomp/seccomp_bpf.c
+++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
@@ -141,6 +141,15 @@
#define SECCOMP_FILTER_FLAG_LOG 2
#endif
+#ifndef PTRACE_SECCOMP_GET_METADATA
+#define PTRACE_SECCOMP_GET_METADATA 0x420d
+
+struct seccomp_metadata {
+ __u64 filter_off; /* Input: which filter */
+ __u64 flags; /* Output: filter's flags */
+};
+#endif
+
#ifndef seccomp
int seccomp(unsigned int op, unsigned int flags, void *args)
{
@@ -2845,6 +2854,58 @@
EXPECT_EQ(errno, EOPNOTSUPP);
}
+TEST(get_metadata)
+{
+ pid_t pid;
+ int pipefd[2];
+ char buf;
+ struct seccomp_metadata md;
+
+ ASSERT_EQ(0, pipe(pipefd));
+
+ pid = fork();
+ ASSERT_GE(pid, 0);
+ if (pid == 0) {
+ struct sock_filter filter[] = {
+ BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
+ };
+ struct sock_fprog prog = {
+ .len = (unsigned short)ARRAY_SIZE(filter),
+ .filter = filter,
+ };
+
+ /* one with log, one without */
+ ASSERT_EQ(0, seccomp(SECCOMP_SET_MODE_FILTER,
+ SECCOMP_FILTER_FLAG_LOG, &prog));
+ ASSERT_EQ(0, seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog));
+
+ ASSERT_EQ(0, close(pipefd[0]));
+ ASSERT_EQ(1, write(pipefd[1], "1", 1));
+ ASSERT_EQ(0, close(pipefd[1]));
+
+ while (1)
+ sleep(100);
+ }
+
+ ASSERT_EQ(0, close(pipefd[1]));
+ ASSERT_EQ(1, read(pipefd[0], &buf, 1));
+
+ ASSERT_EQ(0, ptrace(PTRACE_ATTACH, pid));
+ ASSERT_EQ(pid, waitpid(pid, NULL, 0));
+
+ md.filter_off = 0;
+ ASSERT_EQ(sizeof(md), ptrace(PTRACE_SECCOMP_GET_METADATA, pid, sizeof(md), &md));
+ EXPECT_EQ(md.flags, SECCOMP_FILTER_FLAG_LOG);
+ EXPECT_EQ(md.filter_off, 0);
+
+ md.filter_off = 1;
+ ASSERT_EQ(sizeof(md), ptrace(PTRACE_SECCOMP_GET_METADATA, pid, sizeof(md), &md));
+ EXPECT_EQ(md.flags, 0);
+ EXPECT_EQ(md.filter_off, 1);
+
+ ASSERT_EQ(0, kill(pid, SIGKILL));
+}
+
/*
* TODO:
* - add microbenchmarks
