diff options
Diffstat (limited to 'tools/testing/selftests/bpf/progs/test_ksyms_btf_write_check.c')
-rw-r--r-- | tools/testing/selftests/bpf/progs/test_ksyms_btf_write_check.c | 44 |
1 files changed, 44 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..27109b877714 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_ksyms_btf_write_check.c @@ -0,0 +1,44 @@ +// 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 handler1(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; +} + +__noinline int write_active(int *p) +{ + return p ? (*p = 42) : 0; +} + +SEC("raw_tp/sys_enter") +int handler2(const void *ctx) +{ + int *active; + + active = bpf_this_cpu_ptr(&bpf_prog_active); + write_active(active); + return 0; +} + +char _license[] SEC("license") = "GPL"; |