0afa8e065e
git-subtree-dir: contrib/libfido2 git-subtree-mainline: d586c978b9b4216869e589daa5bbcc33225a0e35 git-subtree-split: a58dee945a5da64d0e97f35a508928e0d17c9cc7
34 lines
1.4 KiB
Plaintext
34 lines
1.4 KiB
Plaintext
libfido2 can be fuzzed using AFL or libFuzzer, with or without
|
|
ASAN/MSAN/UBSAN.
|
|
|
|
AFL is more convenient when fuzzing the path from the authenticator to
|
|
libfido2 in an existing application. To do so, use preload-snoop.c with a real
|
|
authenticator to obtain an initial corpus, rebuild libfido2 with -DFUZZ=ON, and
|
|
use preload-fuzz.c to read device data from stdin.
|
|
|
|
libFuzzer is better suited for bespoke fuzzers; see fuzz_cred.c, fuzz_credman.c,
|
|
fuzz_assert.c, fuzz_hid.c, and fuzz_mgmt.c for examples. To build these
|
|
harnesses, use -DFUZZ=ON -DLIBFUZZER=ON.
|
|
|
|
To run under ASAN/MSAN/UBSAN, libfido2 needs to be linked against flavours of
|
|
libcbor and OpenSSL built with the respective sanitiser. In order to keep
|
|
memory utilisation at a manageable level, you can either enforce limits at
|
|
the OS level (e.g. cgroups on Linux), or patch libcbor with the diff below.
|
|
|
|
diff --git src/cbor/internal/memory_utils.c src/cbor/internal/memory_utils.c
|
|
index aa049a2..e294b38 100644
|
|
--- src/cbor/internal/memory_utils.c
|
|
+++ src/cbor/internal/memory_utils.c
|
|
@@ -28,7 +28,10 @@ bool _cbor_safe_to_multiply(size_t a, size_t b) {
|
|
|
|
void* _cbor_alloc_multiple(size_t item_size, size_t item_count) {
|
|
if (_cbor_safe_to_multiply(item_size, item_count)) {
|
|
- return _CBOR_MALLOC(item_size * item_count);
|
|
+ if (item_count > 1000) {
|
|
+ return NULL;
|
|
+ } else
|
|
+ return _CBOR_MALLOC(item_size * item_count);
|
|
} else {
|
|
return NULL;
|
|
}
|