diff options
author | Hao Luo <haoluo@google.com> | 2022-01-06 12:55:25 -0800 |
---|---|---|
committer | Andrii Nakryiko <andrii@kernel.org> | 2022-01-06 15:20:49 -0800 |
commit | 44bab87d8ca6f0544a9f8fc97bdf33aa5b3c899e (patch) | |
tree | e88c204993400047827074a50eb71bf3e50319bc | |
parent | e59618f0f46fa6cf86d5b82380e0f453756b282b (diff) | |
download | linux-44bab87d8ca6f0544a9f8fc97bdf33aa5b3c899e.tar.bz2 |
bpf/selftests: Test bpf_d_path on rdonly_mem.
The second parameter of bpf_d_path() can only accept writable
memories. Rdonly_mem obtained from bpf_per_cpu_ptr() can not
be passed into bpf_d_path for modification. This patch adds
a selftest to verify this behavior.
Signed-off-by: Hao Luo <haoluo@google.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220106205525.2116218-1-haoluo@google.com
-rw-r--r-- | tools/testing/selftests/bpf/prog_tests/d_path.c | 22 | ||||
-rw-r--r-- | tools/testing/selftests/bpf/progs/test_d_path_check_rdonly_mem.c | 28 |
2 files changed, 49 insertions, 1 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/d_path.c b/tools/testing/selftests/bpf/prog_tests/d_path.c index 0a577a248d34..32fc5b3b5cf6 100644 --- a/tools/testing/selftests/bpf/prog_tests/d_path.c +++ b/tools/testing/selftests/bpf/prog_tests/d_path.c @@ -9,6 +9,7 @@ #define MAX_FILES 7 #include "test_d_path.skel.h" +#include "test_d_path_check_rdonly_mem.skel.h" static int duration; @@ -99,7 +100,7 @@ out_close: return ret; } -void test_d_path(void) +static void test_d_path_basic(void) { struct test_d_path__bss *bss; struct test_d_path *skel; @@ -155,3 +156,22 @@ void test_d_path(void) cleanup: test_d_path__destroy(skel); } + +static void test_d_path_check_rdonly_mem(void) +{ + struct test_d_path_check_rdonly_mem *skel; + + skel = test_d_path_check_rdonly_mem__open_and_load(); + ASSERT_ERR_PTR(skel, "unexpected_load_overwriting_rdonly_mem"); + + test_d_path_check_rdonly_mem__destroy(skel); +} + +void test_d_path(void) +{ + if (test__start_subtest("basic")) + test_d_path_basic(); + + if (test__start_subtest("check_rdonly_mem")) + test_d_path_check_rdonly_mem(); +} diff --git a/tools/testing/selftests/bpf/progs/test_d_path_check_rdonly_mem.c b/tools/testing/selftests/bpf/progs/test_d_path_check_rdonly_mem.c new file mode 100644 index 000000000000..27c27cff6a3a --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_d_path_check_rdonly_mem.c @@ -0,0 +1,28 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Google */ + +#include "vmlinux.h" +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h> + +extern const int bpf_prog_active __ksym; + +SEC("fentry/security_inode_getattr") +int BPF_PROG(d_path_check_rdonly_mem, struct path *path, struct kstat *stat, + __u32 request_mask, unsigned int query_flags) +{ + void *active; + __u32 cpu; + + cpu = bpf_get_smp_processor_id(); + active = (void *)bpf_per_cpu_ptr(&bpf_prog_active, cpu); + if (active) { + /* FAIL here! 'active' points to readonly memory. bpf helpers + * that update its arguments can not write into it. + */ + bpf_d_path(path, active, sizeof(int)); + } + return 0; +} + +char _license[] SEC("license") = "GPL"; |