Re: [PATCH v2 4/6] selftests/bpf: Add test for bpf_ima_file_hash()

On 2/15/22 5:40 AM, Roberto Sassu wrote:

Modify the existing IMA test to call bpf_ima_file_hash() and update the expected result accordingly.

Signed-off-by: Roberto Sassu roberto.sassu@huawei.com

.../selftests/bpf/prog_tests/test_ima.c | 29 ++++++++++++++++--- tools/testing/selftests/bpf/progs/ima.c | 10 +++++-- 2 files changed, 33 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/test_ima.c b/tools/testing/selftests/bpf/prog_tests/test_ima.c index 97d8a6f84f4a..62bf0e830453 100644 --- a/tools/testing/selftests/bpf/prog_tests/test_ima.c +++ b/tools/testing/selftests/bpf/prog_tests/test_ima.c @@ -13,9 +13,10 @@ #include "ima.skel.h" -static int run_measured_process(const char *measured_dir, u32 *monitored_pid) +static int run_measured_process(const char *measured_dir, u32 *monitored_pid,

• 		bool *use_ima_file_hash)
  

  {

• int child_pid, child_status;

• int err, child_pid, child_status;

child_pid = fork(); if (child_pid == 0) { @@ -24,6 +25,21 @@ static int run_measured_process(const char *measured_dir, u32 *monitored_pid) NULL); exit(errno);

• } else if (child_pid > 0) {

• waitpid(child_pid, &child_status, 0);
  

• err = WEXITSTATUS(child_status);
  

• if (err)
  

• 	return err;
  

• }
• child_pid = fork();
• if (child_pid == 0) {

• *monitored_pid = getpid();
  

• *use_ima_file_hash = true;
  

• execlp("./ima_setup.sh", "./ima_setup.sh", "run", measured_dir,
  

•        NULL);
  

• exit(errno);
  

• } else if (child_pid > 0) { waitpid(child_pid, &child_status, 0); return WEXITSTATUS(child_status);

@@ -72,12 +88,17 @@ void test_test_ima(void) if (CHECK(err, "failed to run command", "%s, errno = %d\n", cmd, errno)) goto close_clean;

• err = run_measured_process(measured_dir, &skel->bss->monitored_pid);

• err = run_measured_process(measured_dir, &skel->bss->monitored_pid,

• 		   &skel->bss->use_ima_file_hash);
  

  if (CHECK(err, "run_measured_process", "err = %d\n", err)) goto close_clean;

err = ring_buffer__consume(ringbuf);

• ASSERT_EQ(err, 1, "num_samples_or_err");

• /*

• * 1 sample with use_ima_file_hash = false
  

• * 2 samples with use_ima_file_hash = true (./ima_setup.sh, /bin/true)
  

• */
  

• ASSERT_EQ(err, 3, "num_samples_or_err"); ASSERT_NEQ(ima_hash_from_bpf, 0, "ima_hash");

close_clean: diff --git a/tools/testing/selftests/bpf/progs/ima.c b/tools/testing/selftests/bpf/progs/ima.c index 96060ff4ffc6..9bb63f96cfc0 100644 --- a/tools/testing/selftests/bpf/progs/ima.c +++ b/tools/testing/selftests/bpf/progs/ima.c @@ -18,6 +18,8 @@ struct { char _license[] SEC("license") = "GPL"; +bool use_ima_file_hash;

This can be statis.

SEC("lsm.s/bprm_committed_creds") void BPF_PROG(ima, struct linux_binprm *bprm) { @@ -28,8 +30,12 @@ void BPF_PROG(ima, struct linux_binprm *bprm) pid = bpf_get_current_pid_tgid() >> 32; if (pid == monitored_pid) {

I also noticed monitored_pid is defined in several bpf. Potentially could be made static. This isn't introduced in this patch though.

• ret = bpf_ima_inode_hash(bprm->file->f_inode, &ima_hash,
  

• 			 sizeof(ima_hash));
  

• if (!use_ima_file_hash)
  

• 	ret = bpf_ima_inode_hash(bprm->file->f_inode, &ima_hash,
  

• 				 sizeof(ima_hash));
  

• else
  

• 	ret = bpf_ima_file_hash(bprm->file, &ima_hash,
  

• 				sizeof(ima_hash));
  

  if (ret < 0 || ima_hash == 0) return;

thanks, -- Shuah