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>
This commit is contained in:
Tycho Andersen 2018-02-20 19:47:47 -07:00 committed by Kees Cook
parent 63bb0045b9
commit d057dc4e35

View File

@ -141,6 +141,15 @@ struct seccomp_data {
#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 @@ TEST(get_action_avail)
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