diff --git a/tools/testing/selftests/bpf/prog_tests/test_struct_ops_refcounted.c b/tools/testing/selftests/bpf/prog_tests/test_struct_ops_refcounted.c new file mode 100644 index 000000000000..e290a2f6db95 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/test_struct_ops_refcounted.c @@ -0,0 +1,12 @@ +#include + +#include "struct_ops_refcounted.skel.h" +#include "struct_ops_refcounted_fail__ref_leak.skel.h" +#include "struct_ops_refcounted_fail__global_subprog.skel.h" + +void test_struct_ops_refcounted(void) +{ + RUN_TESTS(struct_ops_refcounted); + RUN_TESTS(struct_ops_refcounted_fail__ref_leak); + RUN_TESTS(struct_ops_refcounted_fail__global_subprog); +} diff --git a/tools/testing/selftests/bpf/progs/struct_ops_refcounted.c b/tools/testing/selftests/bpf/progs/struct_ops_refcounted.c new file mode 100644 index 000000000000..76dcb6089d7f --- /dev/null +++ b/tools/testing/selftests/bpf/progs/struct_ops_refcounted.c @@ -0,0 +1,31 @@ +#include +#include +#include "../test_kmods/bpf_testmod.h" +#include "bpf_misc.h" + +char _license[] SEC("license") = "GPL"; + +__attribute__((nomerge)) extern void bpf_task_release(struct task_struct *p) __ksym; + +/* This is a test BPF program that uses struct_ops to access a referenced + * kptr argument. This is a test for the verifier to ensure that it + * 1) recongnizes the task as a referenced object (i.e., ref_obj_id > 0), and + * 2) the same reference can be acquired from multiple paths as long as it + * has not been released. + */ +SEC("struct_ops/test_refcounted") +int BPF_PROG(refcounted, int dummy, struct task_struct *task) +{ + if (dummy == 1) + bpf_task_release(task); + else + bpf_task_release(task); + return 0; +} + +SEC(".struct_ops.link") +struct bpf_testmod_ops testmod_refcounted = { + .test_refcounted = (void *)refcounted, +}; + + diff --git a/tools/testing/selftests/bpf/progs/struct_ops_refcounted_fail__global_subprog.c b/tools/testing/selftests/bpf/progs/struct_ops_refcounted_fail__global_subprog.c new file mode 100644 index 000000000000..ae074aa62852 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/struct_ops_refcounted_fail__global_subprog.c @@ -0,0 +1,39 @@ +#include +#include +#include "../test_kmods/bpf_testmod.h" +#include "bpf_misc.h" + +char _license[] SEC("license") = "GPL"; + +extern void bpf_task_release(struct task_struct *p) __ksym; + +__noinline int subprog_release(__u64 *ctx __arg_ctx) +{ + struct task_struct *task = (struct task_struct *)ctx[1]; + int dummy = (int)ctx[0]; + + bpf_task_release(task); + + return dummy + 1; +} + +/* Test that the verifier rejects a program that contains a global + * subprogram with referenced kptr arguments + */ +SEC("struct_ops/test_refcounted") +__failure __log_level(2) +__msg("Validating subprog_release() func#1...") +__msg("invalid bpf_context access off=8. Reference may already be released") +int refcounted_fail__global_subprog(unsigned long long *ctx) +{ + struct task_struct *task = (struct task_struct *)ctx[1]; + + bpf_task_release(task); + + return subprog_release(ctx); +} + +SEC(".struct_ops.link") +struct bpf_testmod_ops testmod_ref_acquire = { + .test_refcounted = (void *)refcounted_fail__global_subprog, +}; diff --git a/tools/testing/selftests/bpf/progs/struct_ops_refcounted_fail__ref_leak.c b/tools/testing/selftests/bpf/progs/struct_ops_refcounted_fail__ref_leak.c new file mode 100644 index 000000000000..e945b1a04294 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/struct_ops_refcounted_fail__ref_leak.c @@ -0,0 +1,22 @@ +#include +#include +#include "../test_kmods/bpf_testmod.h" +#include "bpf_misc.h" + +char _license[] SEC("license") = "GPL"; + +/* Test that the verifier rejects a program that acquires a referenced + * kptr through context without releasing the reference + */ +SEC("struct_ops/test_refcounted") +__failure __msg("Unreleased reference id=1 alloc_insn=0") +int BPF_PROG(refcounted_fail__ref_leak, int dummy, + struct task_struct *task) +{ + return 0; +} + +SEC(".struct_ops.link") +struct bpf_testmod_ops testmod_ref_acquire = { + .test_refcounted = (void *)refcounted_fail__ref_leak, +}; diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c index cc9dde507aba..802cbd871035 100644 --- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c +++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c @@ -1176,10 +1176,17 @@ static int bpf_testmod_ops__test_maybe_null(int dummy, return 0; } +static int bpf_testmod_ops__test_refcounted(int dummy, + struct task_struct *task__ref) +{ + return 0; +} + static struct bpf_testmod_ops __bpf_testmod_ops = { .test_1 = bpf_testmod_test_1, .test_2 = bpf_testmod_test_2, .test_maybe_null = bpf_testmod_ops__test_maybe_null, + .test_refcounted = bpf_testmod_ops__test_refcounted, }; struct bpf_struct_ops bpf_bpf_testmod_ops = { diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.h b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.h index 356803d1c10e..c57b2f9dab10 100644 --- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.h +++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.h @@ -36,6 +36,8 @@ struct bpf_testmod_ops { /* Used to test nullable arguments. */ int (*test_maybe_null)(int dummy, struct task_struct *task); int (*unsupported_ops)(void); + /* Used to test ref_acquired arguments. */ + int (*test_refcounted)(int dummy, struct task_struct *task); /* The following fields are used to test shadow copies. */ char onebyte;