crypto/sha512: fix casting of d.nx in UnmarshalBinary
Fixes #29541
Change-Id: I006915b020b6e710298c32c05e3de77a7f9b54f3
GitHub-Last-Rev: c7a90a4bbe17fd1904c0942e8b343264fb85cba1
GitHub-Pull-Request: golang/go#29542
Reviewed-on: https://go-review.googlesource.com/c/156277
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/src/crypto/sha512/sha512.go b/src/crypto/sha512/sha512.go
index 24fde7d..c685319 100644
--- a/src/crypto/sha512/sha512.go
+++ b/src/crypto/sha512/sha512.go
@@ -191,7 +191,7 @@
b, d.h[7] = consumeUint64(b)
b = b[copy(d.x[:], b):]
b, d.len = consumeUint64(b)
- d.nx = int(d.len) % chunk
+ d.nx = int(d.len % chunk)
return nil
}
diff --git a/src/crypto/sha512/sha512_test.go b/src/crypto/sha512/sha512_test.go
index 4423cf5..96a1aa6 100644
--- a/src/crypto/sha512/sha512_test.go
+++ b/src/crypto/sha512/sha512_test.go
@@ -11,6 +11,7 @@
"crypto/rand"
"encoding"
"encoding/hex"
+ "fmt"
"hash"
"io"
"testing"
@@ -831,6 +832,62 @@
}
}
+// Tests for unmarshaling hashes that have hashed a large amount of data
+// The initial hash generation is omitted from the test, because it takes a long time.
+// The test contains some already-generated states, and their expected sums
+// Tests a problem that is outlined in Github issue #29541
+// The problem is triggered when an amount of data has been hashed for which
+// the data length has a 1 in the 32nd bit. When casted to int, this changes
+// the sign of the value, and causes the modulus operation to return a
+// different result.
+type unmarshalTest struct {
+ state string
+ sum string
+}
+
+var largeUnmarshalTests = []unmarshalTest{
+ // Data length: 6_565_544_823
+ unmarshalTest{
+ state: "sha\aηe\x0f\x0f\xe1r]#\aoJ!.{5B\xe4\x140\x91\xdd\x00a\xe1\xb3E&\xb9\xbb\aJ\x9f^\x9f\x03ͺD\x96H\x80\xb0X\x9d\xdeʸ\f\xf7:\xd5\xe6'\xb9\x93f\xddA\xf0~\xe1\x02\x14\x00\x01\x02\x03\x04\x05\x06\a\b\t\n\v\f\r\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuv\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x87VCw",
+ sum: "12d612357a1dbc74a28883dff79b83e7d2b881ae40d7a67fd7305490bc8a641cd1ce9ece598192080d6e9ac7e75d5988567a58a9812991299eb99a04ecb69523",
+ },
+ unmarshalTest{
+ state: "sha\a2\xd2\xdc\xf5\xd7\xe2\xf9\x97\xaa\xe7}Fϱ\xbc\x8e\xbf\x12h\x83Z\xa1\xc7\xf5p>bfS T\xea\xee\x1e\xa6Z\x9c\xa4ڶ\u0086\bn\xe47\x8fsGs3\xe0\xda\\\x9dqZ\xa5\xf6\xd0kM\xa1\xf2\x00\x01\x02\x03\x04\x05\x06\a\b\t\n\v\f\r\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuv\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\xa7VCw",
+ sum: "94a04b9a901254cd94ca0313557e4be3ab1ca86e920c1f3efdc22d361e9ae12be66bc6d6dc5db79a0a4aa6eca6f293c1e9095bbae127ae405f6c325478343299",
+ },
+}
+
+func safeSum(h hash.Hash) (sum []byte, err error) {
+ defer func() {
+ if r := recover(); r != nil {
+ err = fmt.Errorf("sum panic: %v", r)
+ }
+ }()
+
+ return h.Sum(nil), nil
+}
+
+func TestLargeHashes(t *testing.T) {
+ for i, test := range largeUnmarshalTests {
+
+ h := New()
+ if err := h.(encoding.BinaryUnmarshaler).UnmarshalBinary([]byte(test.state)); err != nil {
+ t.Errorf("test %d could not unmarshal: %v", i, err)
+ continue
+ }
+
+ sum, err := safeSum(h)
+ if err != nil {
+ t.Errorf("test %d could not sum: %v", i, err)
+ continue
+ }
+
+ if fmt.Sprintf("%x", sum) != test.sum {
+ t.Errorf("test %d sum mismatch: expect %s got %x", i, test.sum, sum)
+ }
+ }
+}
+
var bench = New()
var buf = make([]byte, 8192)
