Fuzz introspector
For issues and ideas: https://github.com/ossf/fuzz-introspector/issues

Fuzzer details

Fuzzer: fuzz

Call tree

The calltree shows the control flow of the fuzzer. This is overlaid with coverage information to display how much of the potential code a fuzzer can reach is in fact covered at runtime. In the following there is a link to a detailed calltree visualisation as well as a bitmap showing a high-level view of the calltree. For further information about these topics please see the glossary for full calltree and calltree overview

Call tree overview bitmap:

The distribution of callsites in terms of coloring is
Color Runtime hitcount Callsite count Percentage
red 0 493 90.4%
gold [1:9] 0 0.0%
yellow [10:29] 0 0.0%
greenyellow [30:49] 0 0.0%
lawngreen 50+ 52 9.54%
All colors 545 100

Fuzz blockers

The following nodes represent call sites where fuzz blockers occur.

Amount of callsites blocked Calltree index Parent function Callsite Largest blocked function
188 131 LLVMFuzzerTestOneInput call site: 00131 mg_vxprintf
95 401 fn(mg_connection*, int, void*, void*) call site: 00401 mg_http_serve_file
79 320 LLVMFuzzerTestOneInput call site: 00320 mg_connect
45 498 LLVMFuzzerTestOneInput call site: 00498 mg_mgr_poll
20 15 LLVMFuzzerTestOneInput call site: 00015 mg_http_get_header
15 43 LLVMFuzzerTestOneInput call site: 00043 mg_http_var
11 2 LLVMFuzzerTestOneInput call site: 00002 mg_dns_parse_rr
9 120 LLVMFuzzerTestOneInput call site: 00120 mg_random
8 103 LLVMFuzzerTestOneInput call site: 00103 memcmp
7 88 LLVMFuzzerTestOneInput call site: 00088 mg_base64_final
6 74 LLVMFuzzerTestOneInput call site: 00074 mg_millis
4 82 LLVMFuzzerTestOneInput call site: 00082

Runtime coverage analysis

Covered functions
152
Functions that are reachable but not covered
75
Reachable functions
284
Percentage of reachable functions covered
73.59%
NB: The sum of covered functions and functions that are reachable but not covered need not be equal to Reachable functions . This is because the reachability analysis is an approximation and thus at runtime some functions may be covered that are not included in the reachability analysis. This is a limitation of our static analysis capabilities.
Function name source code lines source lines hit percentage hit

Files reached

filename functions hit
test/fuzz.c 2
src/log.c 5
src/dns.c 10
src/util.c 6
src/http.c 34
src/str.c 16
src/mqtt.c 2
src/sntp.c 2
src/base64.c 6
src/json.c 5
src/net.c 12
src/tls_dummy.c 5
src/net_builtin.c 39
src/event.c 2
src/printf.c 5
src/fmt.c 8
src/iobuf.c 5
src/url.c 3
src/ssi.c 1
src/fs.c 2
src/timer.c 2
src/queue.c 3

Analyses and suggestions

Optimal target analysis

Remaining optimal interesting functions

The following table shows a list of functions that are optimal targets. Optimal targets are identified by finding the functions that in combination, yield a high code coverage.

Func name Functions filename Arg count Args Function depth hitcount instr count bb count cyclomatic complexity Reachable functions Incoming references total cyclomatic complexity Unreached complexity
mg_ws_upgrade /src/mongoose/src/ws.c 3 ['struct.mg_connection *', 'struct.mg_http_message *', 'char *'] 15 0 87 6 3 105 0 500 71
mg_mqtt_connect /src/mongoose/src/mqtt.c 5 ['struct.mg_mgr *', 'char *', 'struct.mg_mqtt_opts *', 'func_type *', 'char *'] 11 0 65 9 4 131 0 520 53
mg_http_next_multipart /src/mongoose/src/http.c 4 ['char *', 'size_t', 'size_t', 'struct.mg_http_part *'] 3 0 499 59 23 7 0 54 41
mg_rpc_process /src/mongoose/src/rpc.c 1 ['struct.mg_rpc_req *'] 16 0 164 15 6 53 0 364 36

Implementing fuzzers that target the above functions will improve reachability such that it becomes:

Functions statically reachable by fuzzers
57.9%
214 / 370
Cyclomatic complexity statically reachable by fuzzers
75.0%
1634 / 2184

All functions overview

If you implement fuzzers for these functions, the status of all functions in the project will be:

Func name Functions filename Args Function call depth Reached by Fuzzers Fuzzers runtime hit Func lines hit % I Count BB Count Cyclomatic complexity Functions reached Reached by functions Accumulated cyclomatic complexity Undiscovered complexity

Files and Directories in report

This section shows which files and directories are considered in this report. The main reason for showing this is fuzz introspector may include more code in the reasoning than is desired. This section helps identify if too many files/directories are included, e.g. third party code, which may be irrelevant for the threat model. In the event too much is included, fuzz introspector supports a configuration file that can exclude data from the report. See the following link for more information on how to create a config file: link

Files in report

Source file Reached by Covered by
[] []
/src/mongoose/src/dns.c ['fuzz'] ['fuzz']
/src/mongoose/src/fs_packed.c [] []
/src/mongoose/src/sys_flash.c [] []
/src/mongoose/src/printf.c ['fuzz'] ['fuzz']
/src/mongoose/src/util.c ['fuzz'] ['fuzz']
/src/mongoose/src/rpc.c [] []
/src/mongoose/src/queue.c ['fuzz'] []
/src/mongoose/src/drivers/w5500.c [] []
/src/mongoose/src/timer.c ['fuzz'] ['fuzz']
/src/mongoose/src/sntp.c ['fuzz'] ['fuzz']
/src/mongoose/src/ssi.c ['fuzz'] []
/src/mongoose/src/md5.c [] []
/src/mongoose/test/driver_mock.c [] []
/src/mongoose/src/net_builtin.c ['fuzz'] ['fuzz']
/src/mongoose/src/ws.c [] []
/src/mongoose/src/sys_dummy.c [] []
/src/mongoose/src/url.c ['fuzz'] ['fuzz']
/src/mongoose/src/ota_dummy.c [] []
/src/mongoose/src/iobuf.c ['fuzz'] ['fuzz']
/src/mongoose/src/log.c ['fuzz'] ['fuzz']
/src/mongoose/src/mqtt.c ['fuzz'] ['fuzz']
/src/mongoose/src/fs_posix.c [] []
/src/mongoose/src/base64.c ['fuzz'] ['fuzz']
/src/mongoose/src/fmt.c ['fuzz'] ['fuzz']
/src/mongoose/src/net.c ['fuzz'] ['fuzz']
/src/mongoose/src/json.c ['fuzz'] ['fuzz']
/src/mongoose/src/fs.c ['fuzz'] ['fuzz']
/src/mongoose/src/sha1.c [] []
/src/mongoose/src/event.c ['fuzz'] ['fuzz']
/src/mongoose/src/tls_dummy.c ['fuzz'] ['fuzz']
/src/mongoose/test/fuzz.c ['fuzz'] ['fuzz']
/src/mongoose/src/str.c ['fuzz'] ['fuzz']
/src/mongoose/src/http.c ['fuzz'] ['fuzz']

Directories in report

Directory
/src/mongoose/src/drivers/
/src/mongoose/src/
/src/mongoose/test/