From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793309237; b=iV9M1M0st3mAOuGn/lp9FXD6WvkTOFugAIPZYQ8/bhPGHEnwBGehGLXrJTUAIT43LQN7 r20vC6/BBwTowpha4vcj0OFeu5uK0HkziKtHcN5X4+Krj9we/9kQhs/TUMrQUKU6E7jbR GPNiD94GTbwnpv4dvpfDum8PR6IIaLDzqLDENOdVNf7xl4m6VjZdgbWzEDD9mo4rTf2GM Kf9IZvhwLrX2f6gKCN1wd/zSt5NphYvuVlOh966YaYqwDlk7jr+j0SY8No0JXtBjOcGBF sHkgrofU8qTjz/u2ETSY0R9S0rgybB4XKUu3ARKdV2gigFO2h7OQjmxhpxzdE9u6GHA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793309237; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=0ojy+UhwC3CeZ0n5OWvhNQedtQf6s/LFGjHqzO8hqIs=; b=tJFBlkSN72gDkhYDf+pbGmdM9GgnV7G19+g947As2qF5PlDbIIxMyh46uzVOdsmmKKVo SPDzuaQXBD75l6hEVYi2EX6BVnQBhYOuNJqx2IeCGdqctjD2IQUrJWjBxJKXbjjHJ4039 HD8PmWzbBvMizSnsvg0rmadTcSdFN3gW50UIjpPQlKhs7diWh4DpoCMQJXtR6CSjxfurV f0l+7Bv91S0/0ggA2kOFwa/r7L8hW2uT4MQ67cFIbZNALwLDIGqyVo07Cq7pMpf1enHmu Z2QFTE95ypwPi1vyDJfuSyOH32HFjjNwNugvpXkgolFScuwA3q4D6O7p2l0D6ezx1Dg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=EVelXOyj; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5A74E606A31A for ; Thu, 29 Oct 2026 21:27:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=EVelXOyj Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9C9DB1F01816; Thu, 29 Oct 2026 21:27:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793309237; bh=0ojy+UhwC3CeZ0n5OWvhNQedtQf6s/LFGjHqzO8hqIs=; h=From:To:Cc:Subject:Date:In-Reply-To:References; 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-Mailing-List: bpf@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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