* [scan] fix crashers when parsing comment
When dealing with comments the parsers was potentially incrementing comi
variable twice. During the second access to com[], comi was possibly
longer than maxTok, causing an out of bound error:
panic: runtime error: index out of range [2048] with length 2048
* * Keep only 1 crasher test string.
* move tests from scan_test.go to fuzz_test.go
Both NSEC and NSEC3 use the same logic to pack the bitmap.
CSYNC.pack also appear to make use of `packDataNsec` so I am giving it
the same treatment by moving the logic in a helper function and making
all those types `len` call use that function.
The byte sequence, when Unpack()-ed and subsequential Pack()-ed created a
panic: runtime error: slice bounds out of range
github.com/miekg/dns.(*Msg).packBufferWithCompressionMap(0xc0000d4000, 0x0, 0x0, 0x0, 0x0, 0x0, 0x100, 0x14, 0x14e80b, 0xbf2d4654d501a3c8, ...)
/Users/chantra/go/src/github.com/miekg/dns/msg.go:868 +0x13a8
Confirmed that Unpacking/Repacking payload described in TestCrashNSEC
did not raise a slice bound out of range panic, added unittests which
failed prior to this change.
```
go test -run TestCrashNSEC
--- FAIL: TestCrashNSEC (0.00s)
types_test.go:135: expected length of 19, got 12
FAIL
exit status 1
FAIL github.com/miekg/dns 0.067s
```
Add easy way to fuzz this dns library, put fuzz related code in fuzz.go
and have a small Makefile.fuzz to be used:
$ make -f Makefile.fuzz build
$ make -f Makefile.fuzz fuzz
Will build and fuzz the library. Both pack/unpack and NewRR are fuzz
targets, but we could open this up.
Josh Soref
Miek Gieben
chantra
Miek Gieben