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b=EVelXOyjABrLv4ULU0RJ3o0XRfVChKl+o20IbGRwJiJwWfg5d3X8Eab6sbLaNktl1 9rUkQa5x+qrwknfzJSgz/j3GID5HWSloiERPoPxeDAhHhkX+djEkKRtx9xuK9twBvK jLyQXeaOwTtCXK0W2lIl6jnJfqHC+R37Cnc6A3+zwpw/7BLUZ6HKLQ1fsbFMBE1DJ3 A2+TLqAs2clx8Djo1RvgjNbdDhG1lI7nUjPgO8lGVPKIdrHjGkhrR+Z3Q6GzptkU6x nC4Y97Tp6gXkR/bqfwmTsDcnuJ6WgGWlb1vXdSgwuBP5aNTJIofrX/jt7k0WnSBotF /kwOMPRd0vsTw== From: Jiri Olsa To: Alexei Starovoitov , Daniel Borkmann Cc: bpf@vger.kernel.org, linux-mm@kvack.org, Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi , Lorenzo Stoakes , John Fastabend , Federico Di Pierro Subject: [PATCH bpf-next 8/8] selftests/bpf: Test user memory kfunc errors Date: Thu, 29 Oct 2026 22:25:51 +0100 Message-ID: <20261029212551.56964-9-jolsa@kernel.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261029212551.56964-1-jolsa@kernel.org> References: <20261029212551.56964-1-jolsa@kernel.org> X-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 04F6A14000C X-Stat-Signature: zbka5sou1gjss4okqjn46nzcce4scdfp X-Rspam-User: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=4.0.1 X-HE-Tag: 1793309237-578856 X-HE-Meta: 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 CKb1Og1n ClgZNiWiLqDce0jk6SUnWPTFd3pzxvd+p9wsqESi2+7mAxAsC/d72/hBSQxKtiD9Kkf+IO9FUnpszLSwtmD8DxqfziyK7902eab7J85PobzqHEV3cQsP5mV47TbAYwQz60P0DtobTY+3IsHvXsNSKjobFT6UIG2ee5Gj/p7oHEprNxbgNk6hW6fNfi0AoXYgC/2ENuOrS8PKLc+cXx/v/Qq77D2lJ6AecvzdvKNOt9V+Hv7v7/yNz8PAo+So9cnZz3EJ0iU4hIvLdKI2i7UgA83Kc0QRWGBGF0HmPXTXWFsuBi1k4jKNNtvMxyQ== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 Test invalid copy arguments, zero-length mapping operations, partial copy faults, and copying to read-only mappings. Verify that a failed unmap leaves the mapping intact, and that non-sleepable programs and programs without CAP_SYS_ADMIN cannot call bpf_user_mmap. Assisted-by: Codex:GPT-6 Signed-off-by: Jiri Olsa --- .../selftests/bpf/prog_tests/user_mem.c | 45 +++++++++++++++++++ tools/testing/selftests/bpf/progs/user_mem.c | 29 ++++++++++++ 2 files changed, 74 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/user_mem.c b/tools/testing/selftests/bpf/prog_tests/user_mem.c index c87620e39abb..f3a35f8e005a 100644 --- a/tools/testing/selftests/bpf/prog_tests/user_mem.c +++ b/tools/testing/selftests/bpf/prog_tests/user_mem.c @@ -263,10 +263,49 @@ static void test_partial_copy_fault(struct user_mem *skel) munmap((void *)addr, second_page_unmapped ? page_size : page_size * 2); } +static void test_zero_length_mapping(struct user_mem *skel) +{ + skel->bss->map_len = 0; + skel->bss->map_prot = PROT_READ | PROT_WRITE; + skel->bss->action = USER_MEM_MMAP; + user_mem_trigger(); + + ASSERT_EQ(skel->bss->user_addr, (unsigned long)-EINVAL, "zero_length_mapping"); +} + +static void test_failed_unmap(struct user_mem *skel) +{ + long page_size = sysconf(_SC_PAGESIZE); + unsigned long addr = ~0UL; + + if (!user_mem_mmap(skel, page_size, PROT_READ | PROT_WRITE, &addr)) + return; + + skel->bss->user_addr = addr; + skel->bss->map_len = 0; + skel->bss->action = USER_MEM_UNMAP; + user_mem_trigger(); + + if (ASSERT_EQ(skel->bss->ret, -EINVAL, "zero_length_unmap")) + check_user_mem_vma((void *)addr, page_size, "rw-p"); + + munmap((void *)addr, page_size); +} + +static void test_invalid_copy(struct user_mem *skel) +{ + ASSERT_EQ(user_mem_copy(skel, 1, sizeof(data), 0), -EFAULT, "bad_copy"); + ASSERT_EQ(user_mem_copy(skel, 1, sizeof(data), 1), -EINVAL, "bad_copy_flags"); + ASSERT_EQ(user_mem_copy(skel, 1, 0, 0), 0, "zero_length_copy"); + ASSERT_EQ(user_mem_copy(skel, 1, 0, 1), -EINVAL, "zero_length_copy_bad_flags"); +} + void test_user_mem(void) { struct user_mem *skel; + RUN_TESTS(user_mem); + skel = user_mem__open_and_load(); if (!ASSERT_OK_PTR(skel, "open_and_load")) return; @@ -287,6 +326,12 @@ void test_user_mem(void) test_copy_to_readonly_mapping(skel); if (test__start_subtest("partial_copy_fault")) test_partial_copy_fault(skel); + if (test__start_subtest("failed_unmap")) + test_failed_unmap(skel); + if (test__start_subtest("invalid_copy")) + test_invalid_copy(skel); + if (test__start_subtest("zero_length_mapping")) + test_zero_length_mapping(skel); out: user_mem__destroy(skel); diff --git a/tools/testing/selftests/bpf/progs/user_mem.c b/tools/testing/selftests/bpf/progs/user_mem.c index 6ebfdc54edad..1ff5be6e3e62 100644 --- a/tools/testing/selftests/bpf/progs/user_mem.c +++ b/tools/testing/selftests/bpf/progs/user_mem.c @@ -80,3 +80,32 @@ int user_mem_test(struct pt_regs *ctx) return 0; } + +SEC("?uprobe//proc/self/exe:user_mem_trigger") +__failure +__msg("program must be sleepable to call sleepable kfunc bpf_user_mmap") +__msg("cannot be used in non-sleepable program") +int user_mem_nonsleepable(struct pt_regs *ctx) +{ + bpf_user_mmap(4096, 1); + return 0; +} + +SEC("?kprobe") +__failure +__msg("program must be sleepable to call sleepable kfunc bpf_user_mmap") +__msg("cannot be used in non-sleepable program") +int user_mem_kprobe(struct pt_regs *ctx) +{ + bpf_user_mmap(4096, 1); + return 0; +} + +SEC("?uprobe.s//proc/self/exe:user_mem_trigger") +__failure_unpriv __caps_unpriv(CAP_BPF | CAP_PERFMON) +__msg_unpriv("calling kernel function bpf_user_mmap is not allowed") +int user_mem_no_sysadmin(struct pt_regs *ctx) +{ + bpf_user_mmap(4096, 1); + return 0; +} -- 2.54.0