From: Hao Luo <haoluo@google.com> mainline inclusion from mainline-v5.17-rc1 commit 9497c458c10b049438ef6e6ddda898edbc3ec6a8 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I4WRPV CVE: CVE-2022-0500 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- 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 Conflicts: tools/testing/selftests/bpf/prog_tests/ksyms_btf.c Signed-off-by: Pu Lehui <pulehui@huawei.com> Reviewed-by: Kuohai Xu <xukuohai@huawei.com> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> --- .../selftests/bpf/prog_tests/ksyms_btf.c | 14 +++++++++ .../bpf/progs/test_ksyms_btf_write_check.c | 29 +++++++++++++++++++ 2 files changed, 43 insertions(+) create mode 100644 tools/testing/selftests/bpf/progs/test_ksyms_btf_write_check.c diff --git a/tools/testing/selftests/bpf/prog_tests/ksyms_btf.c b/tools/testing/selftests/bpf/prog_tests/ksyms_btf.c index b58b775d19f3..97f38d4f6a26 100644 --- a/tools/testing/selftests/bpf/prog_tests/ksyms_btf.c +++ b/tools/testing/selftests/bpf/prog_tests/ksyms_btf.c @@ -6,6 +6,7 @@ #include <bpf/btf.h> #include "test_ksyms_btf.skel.h" #include "test_ksyms_btf_null_check.skel.h" +#include "test_ksyms_btf_write_check.skel.h" static int duration; @@ -81,6 +82,16 @@ static void test_null_check(void) test_ksyms_btf_null_check__destroy(skel); } +static void test_write_check(void) +{ + struct test_ksyms_btf_write_check *skel; + + skel = test_ksyms_btf_write_check__open_and_load(); + CHECK(skel, "skel_open", "unexpected load of a prog writing to ksym memory\n"); + + test_ksyms_btf_write_check__destroy(skel); +} + void test_ksyms_btf(void) { int percpu_datasec; @@ -106,4 +117,7 @@ void test_ksyms_btf(void) if (test__start_subtest("null_check")) test_null_check(); + + if (test__start_subtest("write_check")) + test_write_check(); } 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"; -- 2.20.1