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This adds a --pattern flag for regex patterns #6

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This adds a --pattern flag for regex patterns #6

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8f48974
Add pattern flag
or Apr 7, 2015
3cf6bbb
Add simple working pattern matching
or Apr 7, 2015
64be760
Treat given pattern as regular expression
or Apr 7, 2015
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48 changes: 39 additions & 9 deletions gitbrute.go
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Original file line number Diff line number Diff line change
Expand Up @@ -33,25 +33,41 @@ import (
)

var (
prefix = flag.String("prefix", "bf", "Desired prefix")
force = flag.Bool("force", false, "Re-run, even if current hash matches prefix")
cpu = flag.Int("cpus", runtime.NumCPU(), "Number of CPUs to use. Defaults to number of processors.")
prefix = flag.String("prefix", "", "Desired prefix")
force = flag.Bool("force", false, "Re-run, even if current hash matches prefix")
cpu = flag.Int("cpus", runtime.NumCPU(), "Number of CPUs to use. Defaults to number of processors.")
pattern = flag.String("pattern", "", "Desired pattern")
)

var (
start = time.Now()
startUnix = start.Unix()
)

var (
bytePrefix []byte
patternRx *regexp.Regexp
)

func main() {
flag.Parse()
runtime.GOMAXPROCS(*cpu)
if _, err := strconv.ParseInt(*prefix, 16, 64); err != nil {
log.Fatalf("Prefix %q isn't hex.", *prefix)
if *prefix == "" && *pattern == "" {
log.Fatalf("Need prefix or pattern")
}

if *prefix != "" {
if _, err := strconv.ParseInt(*prefix, 16, 64); err != nil {
log.Fatalf("Prefix %q isn't hex.", *prefix)
}
bytePrefix = []byte(*prefix)
}

if *pattern != "" {
patternRx = regexp.MustCompile(*pattern)
}

hash := curHash()
if strings.HasPrefix(hash, *prefix) && !*force {
if hashMatches([]byte(hash)) && !*force {
return
}

Expand All @@ -65,6 +81,8 @@ func main() {
}
msg := obj[i+2:]

runtime.GOMAXPROCS(*cpu)

possibilities := make(chan try, 512)
go explore(possibilities)

Expand Down Expand Up @@ -96,6 +114,19 @@ var (
commiterDateRx = regexp.MustCompile(`(?m)^committer.+> (.+)`)
)

func hashMatches(hash []byte) bool {
if *prefix != "" {
return bytes.HasPrefix(hash, bytePrefix)
}

m := patternRx.FindSubmatchIndex(hash)
if m == nil {
return false
}

return true
}

func bruteForce(obj []byte, winner chan<- solution, possibilities <-chan try, done <-chan struct{}) {
// blob is the blob to mutate in-place repatedly while testing
// whether we have a match.
Expand All @@ -104,7 +135,6 @@ func bruteForce(obj []byte, winner chan<- solution, possibilities <-chan try, do
commitDate, cdatei := getDate(blob, commiterDateRx)

s1 := sha1.New()
wantHexPrefix := []byte(*prefix)
hexBuf := make([]byte, 0, sha1.Size*2)

for t := range possibilities {
Expand All @@ -118,7 +148,7 @@ func bruteForce(obj []byte, winner chan<- solution, possibilities <-chan try, do
strconv.AppendInt(blob[:cdatei], cd.n, 10)
s1.Reset()
s1.Write(blob)
if !bytes.HasPrefix(hexInPlace(s1.Sum(hexBuf[:0])), wantHexPrefix) {
if !hashMatches(hexInPlace(s1.Sum(hexBuf[:0]))) {
continue
}

Expand Down