pubkey_from_hexstr() was failing, which we didn't notice because we
weren't checking the return value. The problem was that we were passing
it a strlen that was half the actual length.
Relevant error:
[libsecp256k1] illegal argument: !secp256k1_fe_is_zero(&ge->x)
==417723== ERROR: libFuzzer: deadly signal
#7 0x7f5deaacc7fb in abort
#8 0x51b0b0 in secp256k1_default_illegal_callback_fn secp256k1.c
#9 0x51bd8e in secp256k1_ec_pubkey_serialize
#10 0x4e235b in pubkey_to_der bitcoin/pubkey.c:29:7
#11 0x4e2941 in pubkey_cmp bitcoin/pubkey.c:89:2
#12 0x4e333d in bitcoin_redeem_2of2 bitcoin/script.c:144:6
#13 0x4f1396 in run tests/fuzz/fuzz-close_tx.c:78:19
The issue is that common_setup() wasn't called by the fuzz target,
leaving secp256k1_ctx as NULL.
UBSan error:
$ UBSAN_OPTIONS="print_stacktrace=1:halt_on_error=1" \
./fuzz-channel_id crash-1575b41ef09e62e4c09c165e6dc037a110b113f2
INFO: Running with entropic power schedule (0xFF, 100).
INFO: Seed: 1153355603
INFO: Loaded 1 modules (25915 inline 8-bit counters): 25915 [0x563bae7ac3a8, 0x563bae7b28e3),
INFO: Loaded 1 PC tables (25915 PCs): 25915 [0x563bae7b28e8,0x563bae817c98),
./fuzz-channel_id: Running 1 inputs 1 time(s) each.
Running: crash-1575b41ef09e62e4c09c165e6dc037a110b113f2
bitcoin/pubkey.c:22:33: runtime error: null pointer passed as argument 1, which is declared to never be null
external/libwally-core/src/secp256k1/include/secp256k1.h:373:3: note: nonnull attribute specified here
#0 0x563bae41e3db in pubkey_from_der bitcoin/pubkey.c:19:7
#1 0x563bae4205e0 in fromwire_pubkey bitcoin/pubkey.c:111:7
#2 0x563bae46437c in run tests/fuzz/fuzz-channel_id.c:42:3
#3 0x563bae2f6016 in LLVMFuzzerTestOneInput tests/fuzz/libfuzz.c:23:2
#4 0x563bae20a450 in fuzzer::Fuzzer::ExecuteCallback(unsigned char const*, unsigned long)
#5 0x563bae1f4c3f in fuzzer::RunOneTest(fuzzer::Fuzzer*, char const*, unsigned long)
#6 0x563bae1fa6e6 in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long))
#7 0x563bae223052 in main (tests/fuzz/fuzz-channel_id+0x181052) (BuildId: f7f56e14ffc06df54ab732d79ea922e773de1f25)
#8 0x7fa7fa113082 in __libc_start_main
#9 0x563bae1efbdd in _start
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior bitcoin/pubkey.c:22:33 in
No tests currently use it, and if they do we'll want to do some
per-test objects. Otherwise, we are about it introduce a dependency
on common/json_filter.o, which is a can of worms.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
And turn "" includes into full-path (which makes it easier to put
config.h first, and finds some cases check-includes.sh missed
previously).
config.h sets _GNU_SOURCE which really needs to be done before any
'#includes': we mainly got away with it with glibc, but other platforms
like Alpine may have stricter requirements.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Before:
Ten builds, laptop -j5, no ccache:
```
real 0m36.686000-38.956000(38.608+/-0.65)s
user 2m32.864000-42.253000(40.7545+/-2.7)s
sys 0m16.618000-18.316000(17.8531+/-0.48)s
```
Ten builds, laptop -j5, ccache (warm):
```
real 0m8.212000-8.577000(8.39989+/-0.13)s
user 0m12.731000-13.212000(12.9751+/-0.17)s
sys 0m3.697000-3.902000(3.83722+/-0.064)s
```
After:
Ten builds, laptop -j5, no ccache: 8% faster
```
real 0m33.802000-35.773000(35.468+/-0.54)s
user 2m19.073000-27.754000(26.2542+/-2.3)s
sys 0m15.784000-17.173000(16.7165+/-0.37)s
```
Ten builds, laptop -j5, ccache (warm): 1% faster
```
real 0m8.200000-8.485000(8.30138+/-0.097)s
user 0m12.485000-13.100000(12.7344+/-0.19)s
sys 0m3.702000-3.889000(3.78787+/-0.056)s
```
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
I did this by copying the updated bech32 code, and then re-patching in
our minor changes:
1. Headers modded (we need size_t)
2. Explicit length for bech32_encode/decode (not 90).
3. Exposing and bech32_ prefix for convert_bits, charset, charset_rev.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We should actually be including this (as it may define _GNU_SOURCE
etc) before any system headers. But where we include <assert.h> we
often didn't, because check-includes would complain that the headers
included it too.
Weaken that check, and include config.h in C files before assert.h.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This adds a new configuration, --enable-fuzzing (which is more than
welcome to be coupled with --enable-address-sanitizer), to pass the
fuzzer sanitizer argument when compiling objects. This allows libfuzzer
to actually be able "to fuzz" by detecting coverage and be smart when
mutating inputs.
As libfuzzer brings its own ~~fees~~ main(), we compile objects with
fsanitize=fuzzer-no-link, and special-case the linkage of the fuzz
targets.
A "lib" is added to abstract out the interface to the fuzzing tool used.
This allow us to use the same targets to fuzz using AFL, hongfuzz or w/e
by adding their entrypoints into libfuzz. (h/t to practicalswift who
introduced this for bitcoin-core, which i mimiced)
Signed-off-by: Antoine Poinsot <darosior@protonmail.com>
