tools/testing/selftests/bpf/progs/iters_looping.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
   3
   4 #include <errno.h>
   5 #include <string.h>
   6 #include <linux/bpf.h>
   7 #include <bpf/bpf_helpers.h>
   8 #include "bpf_misc.h"
   9
  10 char _license[] SEC("license") = "GPL";
  11
  12 #define ITER_HELPERS                                            \
  13           __imm(bpf_iter_num_new),                              \
  14           __imm(bpf_iter_num_next),                             \
  15           __imm(bpf_iter_num_destroy)
  16
  17 SEC("?raw_tp")
  18 __success
  19 int force_clang_to_emit_btf_for_externs(void *ctx)
  20 {
  21         /* we need this as a workaround to enforce compiler emitting BTF
  22          * information for bpf_iter_num_{new,next,destroy}() kfuncs,
  23          * as, apparently, it doesn't emit it for symbols only referenced from
  24          * assembly (or cleanup attribute, for that matter, as well)
  25          */
  26         bpf_repeat(0);
  27
  28         return 0;
  29 }
  30
  31 SEC("?raw_tp")
  32 __success
  33 int consume_first_item_only(void *ctx)
  34 {
  35         struct bpf_iter_num iter;
  36
  37         asm volatile (
  38                 /* create iterator */
  39                 "r1 = %[iter];"
  40                 "r2 = 0;"
  41                 "r3 = 1000;"
  42                 "call %[bpf_iter_num_new];"
  43
  44                 /* consume first item */
  45                 "r1 = %[iter];"
  46                 "call %[bpf_iter_num_next];"
  47
  48                 "if r0 == 0 goto +1;"
  49                 "r0 = *(u32 *)(r0 + 0);"
  50
  51                 /* destroy iterator */
  52                 "r1 = %[iter];"
  53                 "call %[bpf_iter_num_destroy];"
  54                 :
  55                 : __imm_ptr(iter), ITER_HELPERS
  56                 : __clobber_common
  57         );
  58
  59         return 0;
  60 }
  61
  62 SEC("?raw_tp")
  63 __failure __msg("R0 invalid mem access 'scalar'")
  64 int missing_null_check_fail(void *ctx)
  65 {
  66         struct bpf_iter_num iter;
  67
  68         asm volatile (
  69                 /* create iterator */
  70                 "r1 = %[iter];"
  71                 "r2 = 0;"
  72                 "r3 = 1000;"
  73                 "call %[bpf_iter_num_new];"
  74
  75                 /* consume first element */
  76                 "r1 = %[iter];"
  77                 "call %[bpf_iter_num_next];"
  78
  79                 /* FAIL: deref with no NULL check */
  80                 "r1 = *(u32 *)(r0 + 0);"
  81
  82                 /* destroy iterator */
  83                 "r1 = %[iter];"
  84                 "call %[bpf_iter_num_destroy];"
  85                 :
  86                 : __imm_ptr(iter), ITER_HELPERS
  87                 : __clobber_common
  88         );
  89
  90         return 0;
  91 }
  92
  93 SEC("?raw_tp")
  94 __failure
  95 __msg("invalid access to memory, mem_size=4 off=0 size=8")
  96 __msg("R0 min value is outside of the allowed memory range")
  97 int wrong_sized_read_fail(void *ctx)
  98 {
  99         struct bpf_iter_num iter;
 100
 101         asm volatile (
 102                 /* create iterator */
 103                 "r1 = %[iter];"
 104                 "r2 = 0;"
 105                 "r3 = 1000;"
 106                 "call %[bpf_iter_num_new];"
 107
 108                 /* consume first element */
 109                 "r1 = %[iter];"
 110                 "call %[bpf_iter_num_next];"
 111
 112                 "if r0 == 0 goto +1;"
 113                 /* FAIL: deref more than available 4 bytes */
 114                 "r0 = *(u64 *)(r0 + 0);"
 115
 116                 /* destroy iterator */
 117                 "r1 = %[iter];"
 118                 "call %[bpf_iter_num_destroy];"
 119                 :
 120                 : __imm_ptr(iter), ITER_HELPERS
 121                 : __clobber_common
 122         );
 123
 124         return 0;
 125 }
 126
 127 SEC("?raw_tp")
 128 __success __log_level(2)
 129 __flag(BPF_F_TEST_STATE_FREQ)
 130 int simplest_loop(void *ctx)
 131 {
 132         struct bpf_iter_num iter;
 133
 134         asm volatile (
 135                 "r6 = 0;" /* init sum */
 136
 137                 /* create iterator */
 138                 "r1 = %[iter];"
 139                 "r2 = 0;"
 140                 "r3 = 10;"
 141                 "call %[bpf_iter_num_new];"
 142
 143         "1:"
 144                 /* consume next item */
 145                 "r1 = %[iter];"
 146                 "call %[bpf_iter_num_next];"
 147
 148                 "if r0 == 0 goto 2f;"
 149                 "r0 = *(u32 *)(r0 + 0);"
 150                 "r6 += r0;" /* accumulate sum */
 151                 "goto 1b;"
 152
 153         "2:"
 154                 /* destroy iterator */
 155                 "r1 = %[iter];"
 156                 "call %[bpf_iter_num_destroy];"
 157                 :
 158                 : __imm_ptr(iter), ITER_HELPERS
 159                 : __clobber_common, "r6"
 160         );
 161
 162         return 0;
 163 }