diff options
| author | Alexei Starovoitov <ast@kernel.org> | 2021-12-15 12:35:34 -0800 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2021-12-16 21:41:13 +0100 |
| commit | 7edc3fcbf9a2b2e3df53c9656a9f85bf807affac (patch) | |
| tree | e67f6302d7d49c1c331031619e4f66ab13164907 | |
| parent | 588a25e92458c6efeb7a261d5ca5726f5de89184 (diff) | |
selftest/bpf: Add a test that reads various addresses.
Add a function to bpf_testmod that returns invalid kernel and user addresses.
Then attach an fexit program to that function that tries to read
memory through these addresses.
This logic checks that bpf_probe_read_kernel and BPF_PROBE_MEM logic is sane.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
| -rw-r--r-- | tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c | 20 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/progs/test_module_attach.c | 12 |
2 files changed, 32 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c index 5d52ea2768df..df3b292a8ffe 100644 --- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c +++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c @@ -33,6 +33,22 @@ noinline int bpf_testmod_loop_test(int n) return sum; } +__weak noinline struct file *bpf_testmod_return_ptr(int arg) +{ + static struct file f = {}; + + switch (arg) { + case 1: return (void *)EINVAL; /* user addr */ + case 2: return (void *)0xcafe4a11; /* user addr */ + case 3: return (void *)-EINVAL; /* canonical, but invalid */ + case 4: return (void *)(1ull << 60); /* non-canonical and invalid */ + case 5: return (void *)~(1ull << 30); /* trigger extable */ + case 6: return &f; /* valid addr */ + case 7: return (void *)((long)&f | 1); /* kernel tricks */ + default: return NULL; + } +} + noinline ssize_t bpf_testmod_test_read(struct file *file, struct kobject *kobj, struct bin_attribute *bin_attr, @@ -43,6 +59,10 @@ bpf_testmod_test_read(struct file *file, struct kobject *kobj, .off = off, .len = len, }; + int i = 1; + + while (bpf_testmod_return_ptr(i)) + i++; /* This is always true. Use the check to make sure the compiler * doesn't remove bpf_testmod_loop_test. diff --git a/tools/testing/selftests/bpf/progs/test_module_attach.c b/tools/testing/selftests/bpf/progs/test_module_attach.c index b36857093f71..50ce16d02da7 100644 --- a/tools/testing/selftests/bpf/progs/test_module_attach.c +++ b/tools/testing/selftests/bpf/progs/test_module_attach.c @@ -87,6 +87,18 @@ int BPF_PROG(handle_fexit, return 0; } +SEC("fexit/bpf_testmod_return_ptr") +int BPF_PROG(handle_fexit_ret, int arg, struct file *ret) +{ + long buf = 0; + + bpf_probe_read_kernel(&buf, 8, ret); + bpf_probe_read_kernel(&buf, 8, (char *)ret + 256); + *(volatile long long *)ret; + *(volatile int *)&ret->f_mode; + return 0; +} + __u32 fmod_ret_read_sz = 0; SEC("fmod_ret/bpf_testmod_test_read") |