From 7784140f2bd2d5ae44f2be1507ac25f102006155 Mon Sep 17 00:00:00 2001 From: Dave Barach Date: Wed, 29 Apr 2020 17:04:10 -0400 Subject: misc: binary api fuzz test fixes Add a hook to src/vlibapi/api_shared.c to fuzz (screw up) binary API messages, e.g. by xoring random data into them before processing. We specifically exempt client connection messages, and inband debug CLI messages. We step over msg_id, client index, client context, and sw_if_index. Otherwise, "make test" vectors fail too rapidly to learn anything. The goal is to reduce the number of crashes caused to zero. We're fairly close with this patch. Add vl_msg_api_max_length(void *mp), which returns the maximum plausible length for a binary API message. Use it to hardern vl_api_from_api_to_new_vec(...) which takes an additional argument - message pointer - so it can verify that astr->length is sane. If it's not sane, return a u8 *vector of the form "insane astr->length nnnn\0". Verify array lengths in vl_api_dhcp6_send_client_message_t_handler(...) and vl_api_dhcp6_pd_send_client_message_t_handler(...). Add a fairly effective binary API fuzz hook to the unittest plugin, and modify the "make test" framework.py to pass "api-fuzz { on|off }" to enable API fuzzing: "make API_FUZZ=on TEST=xxx test-debug" or similar Type: improvement Signed-off-by: Dave Barach Change-Id: I0157267652a163c01553d5267620f719cc6c3bde --- src/plugins/unittest/api_fuzz_test.c | 187 +++++++++++++++++++++++++++++++++++ 1 file changed, 187 insertions(+) create mode 100644 src/plugins/unittest/api_fuzz_test.c (limited to 'src/plugins/unittest/api_fuzz_test.c') diff --git a/src/plugins/unittest/api_fuzz_test.c b/src/plugins/unittest/api_fuzz_test.c new file mode 100644 index 00000000000..113835300bb --- /dev/null +++ b/src/plugins/unittest/api_fuzz_test.c @@ -0,0 +1,187 @@ +/* + *------------------------------------------------------------------ + * api_fuzz_test.c - Binary API fuzz hook + * + * Copyright (c) 2020 Cisco and/or its affiliates. + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at: + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + *------------------------------------------------------------------ + */ +#include +#include +#include +#include +#include +#include + +static u32 fuzz_seed = 0xdeaddabe; +static u16 fuzz_first; +static u16 fuzz_cli_first, fuzz_cli_last; + +extern void (*vl_msg_api_fuzz_hook) (u16, void *); + +static void +fuzz_hook (u16 id, void *the_msg) +{ + /* + * Fuzz (aka screw up) this message? Leave connection establishment + * messages alone as well as CLI messages. + */ + if ((id > fuzz_first) && !(id >= fuzz_cli_first && id < fuzz_cli_last)) + { + msgbuf_t *mb; + u8 *limit, *start; + + mb = (msgbuf_t *) (((u8 *) the_msg) - offsetof (msgbuf_t, data)); + + limit = (u8 *) (mb->data + ntohl (mb->data_len)); + + /* + * Leave the first 14 octets alone, aka msg_id, client_index, + * context, sw_if_index + */ + + start = ((u8 *) the_msg) + 14; + + for (; start < limit; start++) + *start ^= (random_u32 (&fuzz_seed) & 0xFF); + } +} + +static void +default_fuzz_config (void) +{ + fuzz_first = vl_msg_api_get_msg_index + ((u8 *) "memclnt_keepalive_reply_e8d4e804"); + fuzz_cli_first = vl_msg_api_get_msg_index ((u8 *) "cli_23bfbfff"); + fuzz_cli_last = vl_msg_api_get_msg_index + ((u8 *) "cli_inband_reply_05879051"); +} + +static clib_error_t * +test_api_fuzz_command_fn (vlib_main_t * vm, + unformat_input_t * input, vlib_cli_command_t * cmd) +{ + u32 tmp; + + default_fuzz_config (); + + if (fuzz_first == 0xFFFF) + { + vlib_cli_output (vm, "Couldn't find 'memclnt_keepalive_reply' ID"); + vlib_cli_output + (vm, "Manual setting required, use 'show api message table'"); + } + + if (fuzz_cli_first == 0xFFFF) + { + vlib_cli_output (vm, "Couldn't find 'cli' ID"); + vlib_cli_output + (vm, "Manual setting required, use 'show api message table'"); + } + + if (fuzz_cli_last == 0xFFFF) + { + vlib_cli_output (vm, "Couldn't find 'cli_inband_reply' ID"); + vlib_cli_output + (vm, "Manual setting required, use 'show api message table'"); + } + + while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT) + { + if (unformat (input, "seed %d", &fuzz_seed)) + ; + else if (unformat (input, "disable") | unformat (input, "off")) + fuzz_first = ~0; + else if (unformat (input, "fuzz-first %d", &tmp)) + fuzz_first = (u16) tmp; + else if (unformat (input, "fuzz-cli-first %d", &tmp)) + fuzz_cli_first = (u16) tmp; + else if (unformat (input, "fuzz-cli-last %d", &tmp)) + fuzz_cli_last = (u16) tmp; + else + break; + } + + if (fuzz_first == 0xFFFF) + { + vl_msg_api_fuzz_hook = 0; + return clib_error_return (0, "fuzz_first is ~0, fuzzing disabled"); + } + vl_msg_api_fuzz_hook = fuzz_hook; + + vlib_cli_output (vm, "Fuzzing enabled: first %d, skip cli range %d - %d", + (u32) fuzz_first, (u32) fuzz_cli_first, + (u32) fuzz_cli_last); + + return 0; +} + +/* *INDENT-OFF* */ +VLIB_CLI_COMMAND (test_api_fuzz, static) = { + .path = "test api fuzz", + .short_help = "test api fuzz [disable][seed nnn]\n" + " [fuzz-first nn][fuzz-cli-first nn][fuzz-cli-last nn]", + .function = test_api_fuzz_command_fn, + }; +/* *INDENT-ON* */ + +static u8 main_loop_enter_enable_api_fuzz; + +static clib_error_t * +api_fuzz_config (vlib_main_t * vm, unformat_input_t * input) +{ + while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT) + { + if (unformat (input, "off") + || unformat (input, "disable") || unformat (input, "no")) + ; /* ok, no action */ + else if (unformat (input, "on") + || unformat (input, "enable") || unformat (input, "yes")) + main_loop_enter_enable_api_fuzz = 1; + else + return clib_error_return (0, "unknown input '%U'", + format_unformat_error, input); + } + return 0; +} + +VLIB_CONFIG_FUNCTION (api_fuzz_config, "api-fuzz"); + +static clib_error_t * +api_fuzz_api_init (vlib_main_t * vm) +{ + /* Are we supposed to fuzz API messages? */ + if (main_loop_enter_enable_api_fuzz == 0) + return 0; + + default_fuzz_config (); + + if (fuzz_first == 0xFFFF) + { + return clib_error_return + (0, "Couldn't find 'memclnt_keepalive_reply' ID"); + } + /* Turn on fuzzing */ + vl_msg_api_fuzz_hook = fuzz_hook; + return 0; +} + +VLIB_API_INIT_FUNCTION (api_fuzz_api_init); + +/* + * fd.io coding-style-patch-verification: ON + * + * Local Variables: + * eval: (c-set-style "gnu") + * End: + */ -- cgit 1.2.3-korg