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| author |   Hao Luo <haoluo@google.com> | 2021-12-16 16:31:52 -0800 |
|---|---|---|
| committer |   Alexei Starovoitov <ast@kernel.org> | 2021-12-18 13:27:41 -0800 |
| commit | 9497c458c10b049438ef6e6ddda898edbc3ec6a8 (patch) | |
| tree | bc4fe9822abbf115f8c1183461bc9fdcb96f9212 /tools/testing/selftests/bpf/progs/test_ksyms_btf_write_check.c | |
| parent | bpf: Add MEM_RDONLY for helper args that are pointers to rdonly mem. (diff) | |
| download | linux-dev-9497c458c10b049438ef6e6ddda898edbc3ec6a8.tar.xz linux-dev-9497c458c10b049438ef6e6ddda898edbc3ec6a8.zip | |
bpf/selftests: Test PTR_TO_RDONLY_MEM
This test verifies that a ksym of non-struct can not be directly
updated.
Signed-off-by: Hao Luo <haoluo@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211217003152.48334-10-haoluo@google.com
Diffstat (limited to '')
| -rw-r--r-- | tools/testing/selftests/bpf/progs/test_ksyms_btf_write_check.c | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/test_ksyms_btf_write_check.c b/tools/testing/selftests/bpf/progs/test_ksyms_btf_write_check.c new file mode 100644 index 000000000000..2180c41cd890 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_ksyms_btf_write_check.c @@ -0,0 +1,29 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Google */ + +#include "vmlinux.h" + +#include <bpf/bpf_helpers.h> + +extern const int bpf_prog_active __ksym; /* int type global var. */ + +SEC("raw_tp/sys_enter") +int handler(const void *ctx) +{ + int *active; + __u32 cpu; + + cpu = bpf_get_smp_processor_id(); + active = (int *)bpf_per_cpu_ptr(&bpf_prog_active, cpu); + if (active) { + /* Kernel memory obtained from bpf_{per,this}_cpu_ptr + * is read-only, should _not_ pass verification. + */ + /* WRITE_ONCE */ + *(volatile int *)active = -1; + } + + return 0; +} + +char _license[] SEC("license") = "GPL"; |