From 696c39011538fe0124fcc0e81ebc44ff7f8623b4 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Thu, 27 Jan 2022 07:46:16 -0800 Subject: [PATCH] selftests/bpf: add a selftest with __user tag Added a selftest with three__user usages: a __user pointer-type argument in bpf_testmod, a __user pointer-type struct member in bpf_testmod, and a __user pointer-type struct member in vmlinux. In all cases, directly accessing the user memory will result verification failure. $ ./test_progs -v -n 22/3 ... libbpf: prog 'test_user1': BPF program load failed: Permission denied libbpf: prog 'test_user1': -- BEGIN PROG LOAD LOG -- R1 type=ctx expected=fp 0: R1=ctx(id=0,off=0,imm=0) R10=fp0 ; int BPF_PROG(test_user1, struct bpf_testmod_btf_type_tag_1 *arg) 0: (79) r1 = *(u64 *)(r1 +0) func 'bpf_testmod_test_btf_type_tag_user_1' arg0 has btf_id 136561 type STRUCT 'bpf_testmod_btf_type_tag_1' 1: R1_w=user_ptr_bpf_testmod_btf_type_tag_1(id=0,off=0,imm=0) ; g = arg->a; 1: (61) r1 = *(u32 *)(r1 +0) R1 invalid mem access 'user_ptr_' ... #22/3 btf_tag/btf_type_tag_user_mod1:OK $ ./test_progs -v -n 22/4 ... libbpf: prog 'test_user2': BPF program load failed: Permission denied libbpf: prog 'test_user2': -- BEGIN PROG LOAD LOG -- R1 type=ctx expected=fp 0: R1=ctx(id=0,off=0,imm=0) R10=fp0 ; int BPF_PROG(test_user2, struct bpf_testmod_btf_type_tag_2 *arg) 0: (79) r1 = *(u64 *)(r1 +0) func 'bpf_testmod_test_btf_type_tag_user_2' arg0 has btf_id 136563 type STRUCT 'bpf_testmod_btf_type_tag_2' 1: R1_w=ptr_bpf_testmod_btf_type_tag_2(id=0,off=0,imm=0) ; g = arg->p->a; 1: (79) r1 = *(u64 *)(r1 +0) ; R1_w=user_ptr_bpf_testmod_btf_type_tag_1(id=0,off=0,imm=0) ; g = arg->p->a; 2: (61) r1 = *(u32 *)(r1 +0) R1 invalid mem access 'user_ptr_' ... #22/4 btf_tag/btf_type_tag_user_mod2:OK $ ./test_progs -v -n 22/5 ... libbpf: prog 'test_sys_getsockname': BPF program load failed: Permission denied libbpf: prog 'test_sys_getsockname': -- BEGIN PROG LOAD LOG -- R1 type=ctx expected=fp 0: R1=ctx(id=0,off=0,imm=0) R10=fp0 ; int BPF_PROG(test_sys_getsockname, int fd, struct sockaddr *usockaddr, 0: (79) r1 = *(u64 *)(r1 +8) func '__sys_getsockname' arg1 has btf_id 2319 type STRUCT 'sockaddr' 1: R1_w=user_ptr_sockaddr(id=0,off=0,imm=0) ; g = usockaddr->sa_family; 1: (69) r1 = *(u16 *)(r1 +0) R1 invalid mem access 'user_ptr_' ... #22/5 btf_tag/btf_type_tag_user_vmlinux:OK Signed-off-by: Yonghong Song Link: https://lore.kernel.org/r/20220127154616.659314-1-yhs@fb.com Signed-off-by: Alexei Starovoitov --- .../selftests/bpf/bpf_testmod/bpf_testmod.c | 18 +++++ tools/testing/selftests/bpf/prog_tests/btf_tag.c | 93 ++++++++++++++++++++++ .../selftests/bpf/progs/btf_type_tag_user.c | 40 ++++++++++ 3 files changed, 151 insertions(+) create mode 100644 tools/testing/selftests/bpf/progs/btf_type_tag_user.c diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c index bdbacf5adcd2..595d32ab285a 100644 --- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c +++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c @@ -21,6 +21,24 @@ bpf_testmod_test_mod_kfunc(int i) *(int *)this_cpu_ptr(&bpf_testmod_ksym_percpu) = i; } +struct bpf_testmod_btf_type_tag_1 { + int a; +}; + +struct bpf_testmod_btf_type_tag_2 { + struct bpf_testmod_btf_type_tag_1 __user *p; +}; + +noinline int +bpf_testmod_test_btf_type_tag_user_1(struct bpf_testmod_btf_type_tag_1 __user *arg) { + return arg->a; +} + +noinline int +bpf_testmod_test_btf_type_tag_user_2(struct bpf_testmod_btf_type_tag_2 *arg) { + return arg->p->a; +} + noinline int bpf_testmod_loop_test(int n) { int i, sum = 0; diff --git a/tools/testing/selftests/bpf/prog_tests/btf_tag.c b/tools/testing/selftests/bpf/prog_tests/btf_tag.c index c4cf27777ff7..f7560b54a6bb 100644 --- a/tools/testing/selftests/bpf/prog_tests/btf_tag.c +++ b/tools/testing/selftests/bpf/prog_tests/btf_tag.c @@ -1,6 +1,7 @@ // SPDX-License-Identifier: GPL-2.0 /* Copyright (c) 2021 Facebook */ #include +#include #include "test_btf_decl_tag.skel.h" /* struct btf_type_tag_test is referenced in btf_type_tag.skel.h */ @@ -8,6 +9,7 @@ struct btf_type_tag_test { int **p; }; #include "btf_type_tag.skel.h" +#include "btf_type_tag_user.skel.h" static void test_btf_decl_tag(void) { @@ -41,10 +43,101 @@ static void test_btf_type_tag(void) btf_type_tag__destroy(skel); } +static void test_btf_type_tag_mod_user(bool load_test_user1) +{ + const char *module_name = "bpf_testmod"; + struct btf *vmlinux_btf, *module_btf; + struct btf_type_tag_user *skel; + __s32 type_id; + int err; + + if (!env.has_testmod) { + test__skip(); + return; + } + + /* skip the test if the module does not have __user tags */ + vmlinux_btf = btf__load_vmlinux_btf(); + if (!ASSERT_OK_PTR(vmlinux_btf, "could not load vmlinux BTF")) + return; + + module_btf = btf__load_module_btf(module_name, vmlinux_btf); + if (!ASSERT_OK_PTR(module_btf, "could not load module BTF")) + goto free_vmlinux_btf; + + type_id = btf__find_by_name_kind(module_btf, "user", BTF_KIND_TYPE_TAG); + if (type_id <= 0) { + printf("%s:SKIP: btf_type_tag attribute not in %s", __func__, module_name); + test__skip(); + goto free_module_btf; + } + + skel = btf_type_tag_user__open(); + if (!ASSERT_OK_PTR(skel, "btf_type_tag_user")) + goto free_module_btf; + + bpf_program__set_autoload(skel->progs.test_sys_getsockname, false); + if (load_test_user1) + bpf_program__set_autoload(skel->progs.test_user2, false); + else + bpf_program__set_autoload(skel->progs.test_user1, false); + + err = btf_type_tag_user__load(skel); + ASSERT_ERR(err, "btf_type_tag_user"); + + btf_type_tag_user__destroy(skel); + +free_module_btf: + btf__free(module_btf); +free_vmlinux_btf: + btf__free(vmlinux_btf); +} + +static void test_btf_type_tag_vmlinux_user(void) +{ + struct btf_type_tag_user *skel; + struct btf *vmlinux_btf; + __s32 type_id; + int err; + + /* skip the test if the vmlinux does not have __user tags */ + vmlinux_btf = btf__load_vmlinux_btf(); + if (!ASSERT_OK_PTR(vmlinux_btf, "could not load vmlinux BTF")) + return; + + type_id = btf__find_by_name_kind(vmlinux_btf, "user", BTF_KIND_TYPE_TAG); + if (type_id <= 0) { + printf("%s:SKIP: btf_type_tag attribute not in vmlinux btf", __func__); + test__skip(); + goto free_vmlinux_btf; + } + + skel = btf_type_tag_user__open(); + if (!ASSERT_OK_PTR(skel, "btf_type_tag_user")) + goto free_vmlinux_btf; + + bpf_program__set_autoload(skel->progs.test_user2, false); + bpf_program__set_autoload(skel->progs.test_user1, false); + + err = btf_type_tag_user__load(skel); + ASSERT_ERR(err, "btf_type_tag_user"); + + btf_type_tag_user__destroy(skel); + +free_vmlinux_btf: + btf__free(vmlinux_btf); +} + void test_btf_tag(void) { if (test__start_subtest("btf_decl_tag")) test_btf_decl_tag(); if (test__start_subtest("btf_type_tag")) test_btf_type_tag(); + if (test__start_subtest("btf_type_tag_user_mod1")) + test_btf_type_tag_mod_user(true); + if (test__start_subtest("btf_type_tag_user_mod2")) + test_btf_type_tag_mod_user(false); + if (test__start_subtest("btf_type_tag_sys_user_vmlinux")) + test_btf_type_tag_vmlinux_user(); } diff --git a/tools/testing/selftests/bpf/progs/btf_type_tag_user.c b/tools/testing/selftests/bpf/progs/btf_type_tag_user.c new file mode 100644 index 000000000000..5523f77c5a44 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/btf_type_tag_user.c @@ -0,0 +1,40 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Facebook */ +#include "vmlinux.h" +#include +#include + +struct bpf_testmod_btf_type_tag_1 { + int a; +}; + +struct bpf_testmod_btf_type_tag_2 { + struct bpf_testmod_btf_type_tag_1 *p; +}; + +int g; + +SEC("fentry/bpf_testmod_test_btf_type_tag_user_1") +int BPF_PROG(test_user1, struct bpf_testmod_btf_type_tag_1 *arg) +{ + g = arg->a; + return 0; +} + +SEC("fentry/bpf_testmod_test_btf_type_tag_user_2") +int BPF_PROG(test_user2, struct bpf_testmod_btf_type_tag_2 *arg) +{ + g = arg->p->a; + return 0; +} + +/* int __sys_getsockname(int fd, struct sockaddr __user *usockaddr, + * int __user *usockaddr_len); + */ +SEC("fentry/__sys_getsockname") +int BPF_PROG(test_sys_getsockname, int fd, struct sockaddr *usockaddr, + int *usockaddr_len) +{ + g = usockaddr->sa_family; + return 0; +} -- 2.11.0