| Message ID | 202009081232.92206075F7@keescook (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 3932fcecd96221e18100055d623b736d0ff873a4 |
| Headers | show |
| Series | selftests/seccomp: Add test for unknown SECCOMP_RET kill behavior | expand |
On 9/8/20 1:35 PM, Kees Cook wrote: > While we testing for the behavior of unknown seccomp filter return > values, there was no test for how it acted in a thread group. Add > a test in the thread group tests for this. > > Signed-off-by: Kees Cook <keescook@chromium.org> > --- > (This is going via the seccomp tree.) Cool. > --- > tools/testing/selftests/seccomp/seccomp_bpf.c | 43 ++++++++++++++++--- > 1 file changed, 37 insertions(+), 6 deletions(-) Reviewed-by: Shuah Khan <skhan@linuxfoundation.org> thanks, -- Shuah
On Tue, Sep 08, 2020 at 12:35:18PM -0700, Kees Cook wrote: > While we testing for the behavior of unknown seccomp filter return s/we/we're/ > values, there was no test for how it acted in a thread group. Add > a test in the thread group tests for this. > > Signed-off-by: Kees Cook <keescook@chromium.org> > --- > (This is going via the seccomp tree.) > --- Thanks! Acked-by: Christian Brauner <christian.brauner@ubuntu.com> > tools/testing/selftests/seccomp/seccomp_bpf.c | 43 ++++++++++++++++--- > 1 file changed, 37 insertions(+), 6 deletions(-) > > diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c > index 7a6d40286a42..bfb382580493 100644 > --- a/tools/testing/selftests/seccomp/seccomp_bpf.c > +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c > @@ -774,8 +774,15 @@ void *kill_thread(void *data) > return (void *)SIBLING_EXIT_UNKILLED; > } > > +enum kill_t { > + KILL_THREAD, > + KILL_PROCESS, > + RET_UNKNOWN > +}; > + > /* Prepare a thread that will kill itself or both of us. */ > -void kill_thread_or_group(struct __test_metadata *_metadata, bool kill_process) > +void kill_thread_or_group(struct __test_metadata *_metadata, > + enum kill_t kill_how) > { > pthread_t thread; > void *status; > @@ -791,11 +798,12 @@ void kill_thread_or_group(struct __test_metadata *_metadata, bool kill_process) > .len = (unsigned short)ARRAY_SIZE(filter_thread), > .filter = filter_thread, > }; > + int kill = kill_how == KILL_PROCESS ? SECCOMP_RET_KILL_PROCESS : 0xAAAAAAAAA; > struct sock_filter filter_process[] = { > BPF_STMT(BPF_LD|BPF_W|BPF_ABS, > offsetof(struct seccomp_data, nr)), > BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_prctl, 0, 1), > - BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL_PROCESS), > + BPF_STMT(BPF_RET|BPF_K, kill), > BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), > }; > struct sock_fprog prog_process = { > @@ -808,13 +816,15 @@ void kill_thread_or_group(struct __test_metadata *_metadata, bool kill_process) > } > > ASSERT_EQ(0, seccomp(SECCOMP_SET_MODE_FILTER, 0, > - kill_process ? &prog_process : &prog_thread)); > + kill_how == KILL_THREAD ? &prog_thread > + : &prog_process)); > > /* > * Add the KILL_THREAD rule again to make sure that the KILL_PROCESS > * flag cannot be downgraded by a new filter. > */ > - ASSERT_EQ(0, seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog_thread)); > + if (kill_how == KILL_PROCESS) > + ASSERT_EQ(0, seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog_thread)); (Ok, meaning that you still need to observe that the thread-group gets taken down not just a single thread.) > > /* Start a thread that will exit immediately. */ > ASSERT_EQ(0, pthread_create(&thread, NULL, kill_thread, (void *)false)); > @@ -842,7 +852,7 @@ TEST(KILL_thread) > child_pid = fork(); > ASSERT_LE(0, child_pid); > if (child_pid == 0) { > - kill_thread_or_group(_metadata, false); > + kill_thread_or_group(_metadata, KILL_THREAD); > _exit(38); > } > > @@ -861,7 +871,7 @@ TEST(KILL_process) > child_pid = fork(); > ASSERT_LE(0, child_pid); > if (child_pid == 0) { > - kill_thread_or_group(_metadata, true); > + kill_thread_or_group(_metadata, KILL_PROCESS); > _exit(38); > } > > @@ -872,6 +882,27 @@ TEST(KILL_process) > ASSERT_EQ(SIGSYS, WTERMSIG(status)); > } > > +TEST(KILL_unknown) > +{ > + int status; > + pid_t child_pid; > + > + child_pid = fork(); > + ASSERT_LE(0, child_pid); > + if (child_pid == 0) { > + kill_thread_or_group(_metadata, RET_UNKNOWN); > + _exit(38); > + } > + > + ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0)); > + > + /* If the entire process was killed, we'll see SIGSYS. */ > + EXPECT_TRUE(WIFSIGNALED(status)) { > + TH_LOG("Unknown SECCOMP_RET is only killing the thread?"); > + } > + ASSERT_EQ(SIGSYS, WTERMSIG(status)); > +} > + > /* TODO(wad) add 64-bit versus 32-bit arg tests. */ > TEST(arg_out_of_range) > { > -- > 2.25.1 > > > -- > Kees Cook
diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c index 7a6d40286a42..bfb382580493 100644 --- a/tools/testing/selftests/seccomp/seccomp_bpf.c +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c @@ -774,8 +774,15 @@ void *kill_thread(void *data) return (void *)SIBLING_EXIT_UNKILLED; } +enum kill_t { + KILL_THREAD, + KILL_PROCESS, + RET_UNKNOWN +}; + /* Prepare a thread that will kill itself or both of us. */ -void kill_thread_or_group(struct __test_metadata *_metadata, bool kill_process) +void kill_thread_or_group(struct __test_metadata *_metadata, + enum kill_t kill_how) { pthread_t thread; void *status; @@ -791,11 +798,12 @@ void kill_thread_or_group(struct __test_metadata *_metadata, bool kill_process) .len = (unsigned short)ARRAY_SIZE(filter_thread), .filter = filter_thread, }; + int kill = kill_how == KILL_PROCESS ? SECCOMP_RET_KILL_PROCESS : 0xAAAAAAAAA; struct sock_filter filter_process[] = { BPF_STMT(BPF_LD|BPF_W|BPF_ABS, offsetof(struct seccomp_data, nr)), BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_prctl, 0, 1), - BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL_PROCESS), + BPF_STMT(BPF_RET|BPF_K, kill), BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), }; struct sock_fprog prog_process = { @@ -808,13 +816,15 @@ void kill_thread_or_group(struct __test_metadata *_metadata, bool kill_process) } ASSERT_EQ(0, seccomp(SECCOMP_SET_MODE_FILTER, 0, - kill_process ? &prog_process : &prog_thread)); + kill_how == KILL_THREAD ? &prog_thread + : &prog_process)); /* * Add the KILL_THREAD rule again to make sure that the KILL_PROCESS * flag cannot be downgraded by a new filter. */ - ASSERT_EQ(0, seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog_thread)); + if (kill_how == KILL_PROCESS) + ASSERT_EQ(0, seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog_thread)); /* Start a thread that will exit immediately. */ ASSERT_EQ(0, pthread_create(&thread, NULL, kill_thread, (void *)false)); @@ -842,7 +852,7 @@ TEST(KILL_thread) child_pid = fork(); ASSERT_LE(0, child_pid); if (child_pid == 0) { - kill_thread_or_group(_metadata, false); + kill_thread_or_group(_metadata, KILL_THREAD); _exit(38); } @@ -861,7 +871,7 @@ TEST(KILL_process) child_pid = fork(); ASSERT_LE(0, child_pid); if (child_pid == 0) { - kill_thread_or_group(_metadata, true); + kill_thread_or_group(_metadata, KILL_PROCESS); _exit(38); } @@ -872,6 +882,27 @@ TEST(KILL_process) ASSERT_EQ(SIGSYS, WTERMSIG(status)); } +TEST(KILL_unknown) +{ + int status; + pid_t child_pid; + + child_pid = fork(); + ASSERT_LE(0, child_pid); + if (child_pid == 0) { + kill_thread_or_group(_metadata, RET_UNKNOWN); + _exit(38); + } + + ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0)); + + /* If the entire process was killed, we'll see SIGSYS. */ + EXPECT_TRUE(WIFSIGNALED(status)) { + TH_LOG("Unknown SECCOMP_RET is only killing the thread?"); + } + ASSERT_EQ(SIGSYS, WTERMSIG(status)); +} + /* TODO(wad) add 64-bit versus 32-bit arg tests. */ TEST(arg_out_of_range) {
While we testing for the behavior of unknown seccomp filter return values, there was no test for how it acted in a thread group. Add a test in the thread group tests for this. Signed-off-by: Kees Cook <keescook@chromium.org> --- (This is going via the seccomp tree.) --- tools/testing/selftests/seccomp/seccomp_bpf.c | 43 ++++++++++++++++--- 1 file changed, 37 insertions(+), 6 deletions(-)