From f25fd6088216bd257902e5c212177cddcb291218 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Mon, 13 Mar 2023 16:58:45 -0700 Subject: [PATCH] selftests/bpf: Add various tests to check helper access into ptr_to_btf_id. Add various tests to check helper access into ptr_to_btf_id. Signed-off-by: Alexei Starovoitov Acked-by: David Vernet Link: https://lore.kernel.org/r/20230313235845.61029-4-alexei.starovoitov@gmail.com Signed-off-by: Martin KaFai Lau --- .../selftests/bpf/progs/task_kfunc_failure.c | 36 +++++++++++++++++++ .../selftests/bpf/progs/task_kfunc_success.c | 4 +++ 2 files changed, 40 insertions(+) diff --git a/tools/testing/selftests/bpf/progs/task_kfunc_failure.c b/tools/testing/selftests/bpf/progs/task_kfunc_failure.c index 002c7f69e47f5..27994d6b29142 100644 --- a/tools/testing/selftests/bpf/progs/task_kfunc_failure.c +++ b/tools/testing/selftests/bpf/progs/task_kfunc_failure.c @@ -301,3 +301,39 @@ int BPF_PROG(task_kfunc_from_lsm_task_free, struct task_struct *task) bpf_task_release(acquired); return 0; } + +SEC("tp_btf/task_newtask") +__failure __msg("access beyond the end of member comm") +int BPF_PROG(task_access_comm1, struct task_struct *task, u64 clone_flags) +{ + bpf_strncmp(task->comm, 17, "foo"); + return 0; +} + +SEC("tp_btf/task_newtask") +__failure __msg("access beyond the end of member comm") +int BPF_PROG(task_access_comm2, struct task_struct *task, u64 clone_flags) +{ + bpf_strncmp(task->comm + 1, 16, "foo"); + return 0; +} + +SEC("tp_btf/task_newtask") +__failure __msg("write into memory") +int BPF_PROG(task_access_comm3, struct task_struct *task, u64 clone_flags) +{ + bpf_probe_read_kernel(task->comm, 16, task->comm); + return 0; +} + +SEC("fentry/__set_task_comm") +__failure __msg("R1 type=ptr_ expected") +int BPF_PROG(task_access_comm4, struct task_struct *task, const char *buf, bool exec) +{ + /* + * task->comm is a legacy ptr_to_btf_id. The verifier cannot guarantee + * its safety. Hence it cannot be accessed with normal load insns. + */ + bpf_strncmp(task->comm, 16, "foo"); + return 0; +} diff --git a/tools/testing/selftests/bpf/progs/task_kfunc_success.c b/tools/testing/selftests/bpf/progs/task_kfunc_success.c index aebc4bb14e7dd..4f61596b0242f 100644 --- a/tools/testing/selftests/bpf/progs/task_kfunc_success.c +++ b/tools/testing/selftests/bpf/progs/task_kfunc_success.c @@ -207,6 +207,10 @@ int BPF_PROG(test_task_from_pid_invalid, struct task_struct *task, u64 clone_fla if (!is_test_kfunc_task()) return 0; + bpf_strncmp(task->comm, 12, "foo"); + bpf_strncmp(task->comm, 16, "foo"); + bpf_strncmp(&task->comm[8], 4, "foo"); + if (is_pid_lookup_valid(-1)) { err = 1; return 0; -- 2.30.2