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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 | // SPDX-License-Identifier: GPL-2.0 /* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */ #include <linux/bpf.h> #include <bpf/bpf_helpers.h> #include "bpf_misc.h" #include "test_user_ringbuf.h" char _license[] SEC("license") = "GPL"; struct { __uint(type, BPF_MAP_TYPE_USER_RINGBUF); } user_ringbuf SEC(".maps"); struct { __uint(type, BPF_MAP_TYPE_RINGBUF); } kernel_ringbuf SEC(".maps"); /* inputs */ int pid, err, val; int read = 0; /* Counter used for end-to-end protocol test */ __u64 kern_mutated = 0; __u64 user_mutated = 0; __u64 expected_user_mutated = 0; static int is_test_process(void) { int cur_pid = bpf_get_current_pid_tgid() >> 32; return cur_pid == pid; } static long record_sample(struct bpf_dynptr *dynptr, void *context) { const struct sample *sample = NULL; struct sample stack_sample; int status; static int num_calls; if (num_calls++ % 2 == 0) { status = bpf_dynptr_read(&stack_sample, sizeof(stack_sample), dynptr, 0, 0); if (status) { bpf_printk("bpf_dynptr_read() failed: %d\n", status); err = 1; return 1; } } else { sample = bpf_dynptr_data(dynptr, 0, sizeof(*sample)); if (!sample) { bpf_printk("Unexpectedly failed to get sample\n"); err = 2; return 1; } stack_sample = *sample; } __sync_fetch_and_add(&read, 1); return 0; } static void handle_sample_msg(const struct test_msg *msg) { switch (msg->msg_op) { case TEST_MSG_OP_INC64: kern_mutated += msg->operand_64; break; case TEST_MSG_OP_INC32: kern_mutated += msg->operand_32; break; case TEST_MSG_OP_MUL64: kern_mutated *= msg->operand_64; break; case TEST_MSG_OP_MUL32: kern_mutated *= msg->operand_32; break; default: bpf_printk("Unrecognized op %d\n", msg->msg_op); err = 2; } } static long read_protocol_msg(struct bpf_dynptr *dynptr, void *context) { const struct test_msg *msg = NULL; msg = bpf_dynptr_data(dynptr, 0, sizeof(*msg)); if (!msg) { err = 1; bpf_printk("Unexpectedly failed to get msg\n"); return 0; } handle_sample_msg(msg); return 0; } static int publish_next_kern_msg(__u32 index, void *context) { struct test_msg *msg = NULL; int operand_64 = TEST_OP_64; int operand_32 = TEST_OP_32; msg = bpf_ringbuf_reserve(&kernel_ringbuf, sizeof(*msg), 0); if (!msg) { err = 4; return 1; } switch (index % TEST_MSG_OP_NUM_OPS) { case TEST_MSG_OP_INC64: msg->operand_64 = operand_64; msg->msg_op = TEST_MSG_OP_INC64; expected_user_mutated += operand_64; break; case TEST_MSG_OP_INC32: msg->operand_32 = operand_32; msg->msg_op = TEST_MSG_OP_INC32; expected_user_mutated += operand_32; break; case TEST_MSG_OP_MUL64: msg->operand_64 = operand_64; msg->msg_op = TEST_MSG_OP_MUL64; expected_user_mutated *= operand_64; break; case TEST_MSG_OP_MUL32: msg->operand_32 = operand_32; msg->msg_op = TEST_MSG_OP_MUL32; expected_user_mutated *= operand_32; break; default: bpf_ringbuf_discard(msg, 0); err = 5; return 1; } bpf_ringbuf_submit(msg, 0); return 0; } static void publish_kern_messages(void) { if (expected_user_mutated != user_mutated) { bpf_printk("%lu != %lu\n", expected_user_mutated, user_mutated); err = 3; return; } bpf_loop(8, publish_next_kern_msg, NULL, 0); } SEC("fentry/" SYS_PREFIX "sys_prctl") int test_user_ringbuf_protocol(void *ctx) { long status = 0; if (!is_test_process()) return 0; status = bpf_user_ringbuf_drain(&user_ringbuf, read_protocol_msg, NULL, 0); if (status < 0) { bpf_printk("Drain returned: %ld\n", status); err = 1; return 0; } publish_kern_messages(); return 0; } SEC("fentry/" SYS_PREFIX "sys_getpgid") int test_user_ringbuf(void *ctx) { if (!is_test_process()) return 0; err = bpf_user_ringbuf_drain(&user_ringbuf, record_sample, NULL, 0); return 0; } static long do_nothing_cb(struct bpf_dynptr *dynptr, void *context) { __sync_fetch_and_add(&read, 1); return 0; } SEC("fentry/" SYS_PREFIX "sys_prlimit64") int test_user_ringbuf_epoll(void *ctx) { long num_samples; if (!is_test_process()) return 0; num_samples = bpf_user_ringbuf_drain(&user_ringbuf, do_nothing_cb, NULL, 0); if (num_samples <= 0) err = 1; return 0; } |