Imported Upstream version 1.3.1upstream/1.3.1

23 files changed, 240 insertions, 94 deletions

diff --git a/src/cmd/6g/ggen.c b/src/cmd/6g/ggen.c
index c385798f2..9665d831b 100644
--- a/src/cmd/6g/ggen.c
+++ b/src/cmd/6g/ggen.c
@@ -943,7 +943,7 @@ cgen_hmul(Node *nl, Node *nr, Node *res)
 	if(t->width == 1) {
 		// byte multiply behaves differently.
 		nodreg(&ax, t, D_AH);
-		nodreg(&dx, t, D_DL);
+		nodreg(&dx, t, D_DX);
 		gmove(&ax, &dx);
 	}
 	nodreg(&dx, t, D_DX);
diff --git a/src/cmd/6g/peep.c b/src/cmd/6g/peep.c
index 0f2720443..24617836f 100644
--- a/src/cmd/6g/peep.c
+++ b/src/cmd/6g/peep.c
@@ -838,6 +838,11 @@ copyu(Prog *p, Adr *v, Adr *s)
 static int
 copyas(Adr *a, Adr *v)
 {
+	if(D_AL <= a->type && a->type <= D_R15B)
+		fatal("use of byte register");
+	if(D_AL <= v->type && v->type <= D_R15B)
+		fatal("use of byte register");
+
 	if(a->type != v->type)
 		return 0;
 	if(regtyp(v))
diff --git a/src/cmd/8g/ggen.c b/src/cmd/8g/ggen.c
index 2285a04e6..5e3140480 100644
--- a/src/cmd/8g/ggen.c
+++ b/src/cmd/8g/ggen.c
@@ -991,7 +991,7 @@ cgen_hmul(Node *nl, Node *nr, Node *res)
 	if(t->width == 1) {
 		// byte multiply behaves differently.
 		nodreg(&ax, t, D_AH);
-		nodreg(&dx, t, D_DL);
+		nodreg(&dx, t, D_DX);
 		gmove(&ax, &dx);
 	}
 	nodreg(&dx, t, D_DX);
diff --git a/src/cmd/8g/peep.c b/src/cmd/8g/peep.c
index a4e516dd3..e2f3a003d 100644
--- a/src/cmd/8g/peep.c
+++ b/src/cmd/8g/peep.c
@@ -634,6 +634,11 @@ copyu(Prog *p, Adr *v, Adr *s)
 static int
 copyas(Adr *a, Adr *v)
 {
+	if(D_AL <= a->type && a->type <= D_BL)
+		fatal("use of byte register");
+	if(D_AL <= v->type && v->type <= D_BL)
+		fatal("use of byte register");
+
 	if(a->type != v->type)
 		return 0;
 	if(regtyp(v))
diff --git a/src/cmd/cgo/gcc.go b/src/cmd/cgo/gcc.go
index 7a802102d..f55cfbac4 100644
--- a/src/cmd/cgo/gcc.go
+++ b/src/cmd/cgo/gcc.go
@@ -552,8 +552,8 @@ func (p *Package) loadDWARF(f *File, names []*Name) {
 				n.Const = fmt.Sprintf("%#x", enumVal[i])
 			}
 		}
+		conv.FinishType(pos)
 	}
-
 }
 
 // mangleName does name mangling to translate names
@@ -926,6 +926,12 @@ type typeConv struct {
 	m       map[dwarf.Type]*Type
 	typedef map[string]ast.Expr
 
+	// Map from types to incomplete pointers to those types.
+	ptrs map[dwarf.Type][]*Type
+
+	// Fields to be processed by godefsField after completing pointers.
+	todoFlds [][]*ast.Field
+
 	// Predeclared types.
 	bool                                   ast.Expr
 	byte                                   ast.Expr // denotes padding
@@ -950,6 +956,7 @@ func (c *typeConv) Init(ptrSize, intSize int64) {
 	c.ptrSize = ptrSize
 	c.intSize = intSize
 	c.m = make(map[dwarf.Type]*Type)
+	c.ptrs = make(map[dwarf.Type][]*Type)
 	c.bool = c.Ident("bool")
 	c.byte = c.Ident("byte")
 	c.int8 = c.Ident("int8")
@@ -1029,6 +1036,32 @@ func (tr *TypeRepr) Set(repr string, fargs ...interface{}) {
 	tr.FormatArgs = fargs
 }
 
+// FinishType completes any outstanding type mapping work.
+// In particular, it resolves incomplete pointer types and also runs
+// godefsFields on any new struct types.
+func (c *typeConv) FinishType(pos token.Pos) {
+	// Completing one pointer type might produce more to complete.
+	// Keep looping until they're all done.
+	for len(c.ptrs) > 0 {
+		for dtype := range c.ptrs {
+			// Note Type might invalidate c.ptrs[dtype].
+			t := c.Type(dtype, pos)
+			for _, ptr := range c.ptrs[dtype] {
+				ptr.Go.(*ast.StarExpr).X = t.Go
+				ptr.C.Set("%s*", t.C)
+			}
+			delete(c.ptrs, dtype)
+		}
+	}
+
+	// Now that pointer types are completed, we can invoke godefsFields
+	// to rewrite struct definitions.
+	for _, fld := range c.todoFlds {
+		godefsFields(fld)
+	}
+	c.todoFlds = nil
+}
+
 // Type returns a *Type with the same memory layout as
 // dtype when used as the type of a variable or a struct field.
 func (c *typeConv) Type(dtype dwarf.Type, pos token.Pos) *Type {
@@ -1068,13 +1101,12 @@ func (c *typeConv) Type(dtype dwarf.Type, pos token.Pos) *Type {
 			t.Go = c.Opaque(t.Size)
 			break
 		}
-		gt := &ast.ArrayType{
-			Len: c.intExpr(dt.Count),
-		}
-		t.Go = gt // publish before recursive call
 		sub := c.Type(dt.Type, pos)
 		t.Align = sub.Align
-		gt.Elt = sub.Go
+		t.Go = &ast.ArrayType{
+			Len: c.intExpr(dt.Count),
+			Elt: sub.Go,
+		}
 		t.C.Set("__typeof__(%s[%d])", sub.C, dt.Count)
 
 	case *dwarf.BoolType:
@@ -1184,11 +1216,10 @@ func (c *typeConv) Type(dtype dwarf.Type, pos token.Pos) *Type {
 			break
 		}
 
-		gt := &ast.StarExpr{}
-		t.Go = gt // publish before recursive call
-		sub := c.Type(dt.Type, pos)
-		gt.X = sub.Go
-		t.C.Set("%s*", sub.C)
+		// Placeholder initialization; completed in FinishType.
+		t.Go = &ast.StarExpr{}
+		t.C.Set("<incomplete>*")
+		c.ptrs[dt.Type] = append(c.ptrs[dt.Type], t)
 
 	case *dwarf.QualType:
 		// Ignore qualifier.
@@ -1265,8 +1296,8 @@ func (c *typeConv) Type(dtype dwarf.Type, pos token.Pos) *Type {
 		}
 		name := c.Ident("_Ctype_" + dt.Name)
 		goIdent[name.Name] = name
-		t.Go = name // publish before recursive call
 		sub := c.Type(dt.Type, pos)
+		t.Go = name
 		t.Size = sub.Size
 		t.Align = sub.Align
 		oldType := typedef[name.Name]
@@ -1604,7 +1635,7 @@ func (c *typeConv) Struct(dt *dwarf.StructType, pos token.Pos) (expr *ast.Struct
 	csyntax = buf.String()
 
 	if *godefs || *cdefs {
-		godefsFields(fld)
+		c.todoFlds = append(c.todoFlds, fld)
 	}
 	expr = &ast.StructType{Fields: &ast.FieldList{List: fld}}
 	return
diff --git a/src/cmd/gc/array.c b/src/cmd/gc/array.c
index 5e53c1ff0..611fc9fbd 100644
--- a/src/cmd/gc/array.c
+++ b/src/cmd/gc/array.c
@@ -108,20 +108,6 @@ arrayadd(Array *array, void *element)
 	arrayset(array, array->length - 1, element);
 }
 
-int32
-arrayindexof(Array *array, void *element)
-{
-	void *p;
-	int32 i;
-
-	for(i = 0; i < array->length; i++) {
-		p = arrayget(array, i);
-		if(memcmp(p, &element, array->size) == 0)
-			return i;
-	}
-	return -1;
-}
-
 void
 arraysort(Array *array, int (*cmp)(const void*, const void*))
 {
diff --git a/src/cmd/gc/bv.c b/src/cmd/gc/bv.c
index 2efbbc565..0e8f8d473 100644
--- a/src/cmd/gc/bv.c
+++ b/src/cmd/gc/bv.c
@@ -9,6 +9,8 @@
 enum {
 	WORDSIZE = sizeof(uint32),
 	WORDBITS = 32,
+	WORDMASK = WORDBITS - 1,
+	WORDSHIFT = 5,
 };
 
 static uintptr
@@ -94,13 +96,35 @@ bvconcat(Bvec *src1, Bvec *src2)
 int
 bvget(Bvec *bv, int32 i)
 {
-	uint32 mask, word;
-
 	if(i < 0 || i >= bv->n)
 		fatal("bvget: index %d is out of bounds with length %d\n", i, bv->n);
-	mask = 1U << (i % WORDBITS);
-	word = bv->b[i / WORDBITS] & mask;
-	return word ? 1 : 0;
+	return (bv->b[i>>WORDSHIFT] >> (i&WORDMASK)) & 1;
+}
+
+// bvnext returns the smallest index >= i for which bvget(bv, i) == 1.
+// If there is no such index, bvnext returns -1.
+int
+bvnext(Bvec *bv, int32 i)
+{
+	uint32 w;
+
+	// Jump i ahead to next word with bits.
+	if((bv->b[i>>WORDSHIFT]>>(i&WORDMASK)) == 0) {
+		i &= ~WORDMASK;
+		i += WORDBITS;
+		while(i < bv->n && bv->b[i>>WORDSHIFT] == 0)
+			i += WORDBITS;
+	}
+	if(i >= bv->n)
+		return -1;
+	
+	// Find 1 bit.
+	w = bv->b[i>>WORDSHIFT]>>(i&WORDMASK);
+	while((w&1) == 0) {
+		w>>=1;
+		i++;
+	}
+	return i;
 }
 
 int
@@ -109,7 +133,7 @@ bvisempty(Bvec *bv)
 	int32 i;
 
 	for(i = 0; i < bv->n; i += WORDBITS)
-		if(bv->b[i / WORDBITS] != 0)
+		if(bv->b[i>>WORDSHIFT] != 0)
 			return 0;
 	return 1;
 }
diff --git a/src/cmd/gc/go.h b/src/cmd/gc/go.h
index 413e71069..ee879f67f 100644
--- a/src/cmd/gc/go.h
+++ b/src/cmd/gc/go.h
@@ -1017,7 +1017,6 @@ int32	arraylength(Array *array);
 void*	arrayget(Array *array, int32 index);
 void	arrayset(Array *array, int32 index, void *element);
 void	arrayadd(Array *array, void *element);
-int32	arrayindexof(Array* array, void *element);
 void	arraysort(Array* array, int (*cmp)(const void*, const void*));
 
 /*
@@ -1043,6 +1042,7 @@ int	bvcmp(Bvec *bv1, Bvec *bv2);
 void	bvcopy(Bvec *dst, Bvec *src);
 Bvec*	bvconcat(Bvec *src1, Bvec *src2);
 int	bvget(Bvec *bv, int32 i);
+int32	bvnext(Bvec *bv, int32 i);
 int	bvisempty(Bvec *bv);
 void	bvnot(Bvec *bv);
 void	bvor(Bvec *dst, Bvec *src1, Bvec *src2);
diff --git a/src/cmd/gc/plive.c b/src/cmd/gc/plive.c
index eb8901733..7a40ab559 100644
--- a/src/cmd/gc/plive.c
+++ b/src/cmd/gc/plive.c
@@ -283,13 +283,30 @@ getvariables(Node *fn)
 			// For arguments and results, the bitmap covers all variables,
 			// so we must include all the variables, even the ones without
 			// pointers.
+			//
+			// The Node.opt field is available for use by optimization passes.
+			// We use it to hold the index of the node in the variables array, plus 1
+			// (so that 0 means the Node is not in the variables array).
+			// Each pass should clear opt when done, but you never know,
+			// so clear them all ourselves too.
+			// The Node.curfn field is supposed to be set to the current function
+			// already, but for some compiler-introduced names it seems not to be,
+			// so fix that here.
+			// Later, when we want to find the index of a node in the variables list,
+			// we will check that n->curfn == curfn and n->opt > 0. Then n->opt - 1
+			// is the index in the variables list.
+			ll->n->opt = nil;
+			ll->n->curfn = curfn;
 			switch(ll->n->class) {
 			case PAUTO:
-				if(haspointers(ll->n->type))
+				if(haspointers(ll->n->type)) {
+					ll->n->opt = (void*)(uintptr)(arraylength(result)+1);
 					arrayadd(result, &ll->n);
+				}
 				break;
 			case PPARAM:
 			case PPARAMOUT:
+				ll->n->opt = (void*)(uintptr)(arraylength(result)+1);
 				arrayadd(result, &ll->n);
 				break;
 			}
@@ -718,14 +735,16 @@ progeffects(Prog *prog, Array *vars, Bvec *uevar, Bvec *varkill, Bvec *avarinit)
 	}
 	if(info.flags & (LeftRead | LeftWrite | LeftAddr)) {
 		from = &prog->from;
-		if (from->node != nil && from->sym != nil) {
+		if (from->node != nil && from->sym != nil && from->node->curfn == curfn) {
 			switch(from->node->class & ~PHEAP) {
 			case PAUTO:
 			case PPARAM:
 			case PPARAMOUT:
-				pos = arrayindexof(vars, from->node);
+				pos = (int)(uintptr)from->node->opt - 1; // index in vars
 				if(pos == -1)
 					goto Next;
+				if(pos >= arraylength(vars) || *(Node**)arrayget(vars, pos) != from->node)
+					fatal("bad bookkeeping in liveness %N %d", from->node, pos);
 				if(from->node->addrtaken) {
 					bvset(avarinit, pos);
 				} else {
@@ -741,14 +760,16 @@ progeffects(Prog *prog, Array *vars, Bvec *uevar, Bvec *varkill, Bvec *avarinit)
 Next:
 	if(info.flags & (RightRead | RightWrite | RightAddr)) {
 		to = &prog->to;
-		if (to->node != nil && to->sym != nil) {
+		if (to->node != nil && to->sym != nil && to->node->curfn == curfn) {
 			switch(to->node->class & ~PHEAP) {
 			case PAUTO:
 			case PPARAM:
 			case PPARAMOUT:
-				pos = arrayindexof(vars, to->node);
+				pos = (int)(uintptr)to->node->opt - 1; // index in vars
 				if(pos == -1)
 					goto Next1;
+				if(pos >= arraylength(vars) || *(Node**)arrayget(vars, pos) != to->node)
+					fatal("bad bookkeeping in liveness %N %d", to->node, pos);
 				if(to->node->addrtaken) {
 					if(prog->as != AVARKILL)
 						bvset(avarinit, pos);
@@ -1020,6 +1041,9 @@ checkptxt(Node *fn, Prog *firstp)
 {
 	Prog *p;
 
+	if(debuglive == 0)
+		return;
+
 	for(p = firstp; p != P; p = p->link) {
 		if(0)
 			print("analyzing '%P'\n", p);
@@ -1172,21 +1196,17 @@ twobitlivepointermap(Liveness *lv, Bvec *liveout, Array *vars, Bvec *args, Bvec
 	vlong xoffset;
 	int32 i;
 
-	for(i = 0; i < arraylength(vars); i++) {
+	for(i = 0; (i = bvnext(liveout, i)) >= 0; i++) {
 		node = *(Node**)arrayget(vars, i);
 		switch(node->class) {
 		case PAUTO:
-			if(bvget(liveout, i)) {
-				xoffset = node->xoffset + stkptrsize;
-				twobitwalktype1(node->type, &xoffset, locals);
-			}
+			xoffset = node->xoffset + stkptrsize;
+			twobitwalktype1(node->type, &xoffset, locals);
 			break;
 		case PPARAM:
 		case PPARAMOUT:
-			if(bvget(liveout, i)) {
-				xoffset = node->xoffset;
-				twobitwalktype1(node->type, &xoffset, args);
-			}
+			xoffset = node->xoffset;
+			twobitwalktype1(node->type, &xoffset, args);
 			break;
 		}
 	}
@@ -1937,6 +1957,7 @@ liveness(Node *fn, Prog *firstp, Sym *argssym, Sym *livesym)
 	Array *cfg, *vars;
 	Liveness *lv;
 	int debugdelta;
+	NodeList *l;
 
 	// Change name to dump debugging information only for a specific function.
 	debugdelta = 0;
@@ -1977,6 +1998,9 @@ liveness(Node *fn, Prog *firstp, Sym *argssym, Sym *livesym)
 	twobitwritesymbol(lv->argslivepointers, argssym);
 
 	// Free everything.
+	for(l=fn->dcl; l != nil; l = l->next)
+		if(l->n != N)
+			l->n->opt = nil;
 	freeliveness(lv);
 	arrayfree(vars);
 	freecfg(cfg);
diff --git a/src/pkg/compress/gzip/gzip.go b/src/pkg/compress/gzip/gzip.go
index 3a0bf54e1..5131d128e 100644
--- a/src/pkg/compress/gzip/gzip.go
+++ b/src/pkg/compress/gzip/gzip.go
@@ -245,7 +245,8 @@ func (z *Writer) Flush() error {
 	return z.err
 }
 
-// Close closes the Writer. It does not close the underlying io.Writer.
+// Close closes the Writer, flushing any unwritten data to the underlying
+// io.Writer, but does not close the underlying io.Writer.
 func (z *Writer) Close() error {
 	if z.err != nil {
 		return z.err
diff --git a/src/pkg/compress/zlib/writer.go b/src/pkg/compress/zlib/writer.go
index fac7e15a7..3b4313a8b 100644
--- a/src/pkg/compress/zlib/writer.go
+++ b/src/pkg/compress/zlib/writer.go
@@ -174,7 +174,8 @@ func (z *Writer) Flush() error {
 	return z.err
 }
 
-// Calling Close does not close the wrapped io.Writer originally passed to NewWriter.
+// Close closes the Writer, flushing any unwritten data to the underlying
+// io.Writer, but does not close the underlying io.Writer.
 func (z *Writer) Close() error {
 	if !z.wroteHeader {
 		z.err = z.writeHeader()
diff --git a/src/pkg/crypto/rsa/pkcs1v15.go b/src/pkg/crypto/rsa/pkcs1v15.go
index d9957aec1..59e8bb5b7 100644
--- a/src/pkg/crypto/rsa/pkcs1v15.go
+++ b/src/pkg/crypto/rsa/pkcs1v15.go
@@ -53,11 +53,14 @@ func DecryptPKCS1v15(rand io.Reader, priv *PrivateKey, ciphertext []byte) (out [
 	if err := checkPub(&priv.PublicKey); err != nil {
 		return nil, err
 	}
-	valid, out, err := decryptPKCS1v15(rand, priv, ciphertext)
-	if err == nil && valid == 0 {
-		err = ErrDecryption
+	valid, out, index, err := decryptPKCS1v15(rand, priv, ciphertext)
+	if err != nil {
+		return
 	}
-
+	if valid == 0 {
+		return nil, ErrDecryption
+	}
+	out = out[index:]
 	return
 }
 
@@ -80,21 +83,32 @@ func DecryptPKCS1v15SessionKey(rand io.Reader, priv *PrivateKey, ciphertext []by
 	}
 	k := (priv.N.BitLen() + 7) / 8
 	if k-(len(key)+3+8) < 0 {
-		err = ErrDecryption
-		return
+		return ErrDecryption
 	}
 
-	valid, msg, err := decryptPKCS1v15(rand, priv, ciphertext)
+	valid, em, index, err := decryptPKCS1v15(rand, priv, ciphertext)
 	if err != nil {
 		return
 	}
 
-	valid &= subtle.ConstantTimeEq(int32(len(msg)), int32(len(key)))
-	subtle.ConstantTimeCopy(valid, key, msg)
+	if len(em) != k {
+		// This should be impossible because decryptPKCS1v15 always
+		// returns the full slice.
+		return ErrDecryption
+	}
+
+	valid &= subtle.ConstantTimeEq(int32(len(em)-index), int32(len(key)))
+	subtle.ConstantTimeCopy(valid, key, em[len(em)-len(key):])
 	return
 }
 
-func decryptPKCS1v15(rand io.Reader, priv *PrivateKey, ciphertext []byte) (valid int, msg []byte, err error) {
+// decryptPKCS1v15 decrypts ciphertext using priv and blinds the operation if
+// rand is not nil. It returns one or zero in valid that indicates whether the
+// plaintext was correctly structured. In either case, the plaintext is
+// returned in em so that it may be read independently of whether it was valid
+// in order to maintain constant memory access patterns. If the plaintext was
+// valid then index contains the index of the original message in em.
+func decryptPKCS1v15(rand io.Reader, priv *PrivateKey, ciphertext []byte) (valid int, em []byte, index int, err error) {
 	k := (priv.N.BitLen() + 7) / 8
 	if k < 11 {
 		err = ErrDecryption
@@ -107,7 +121,7 @@ func decryptPKCS1v15(rand io.Reader, priv *PrivateKey, ciphertext []byte) (valid
 		return
 	}
 
-	em := leftPad(m.Bytes(), k)
+	em = leftPad(m.Bytes(), k)
 	firstByteIsZero := subtle.ConstantTimeByteEq(em[0], 0)
 	secondByteIsTwo := subtle.ConstantTimeByteEq(em[1], 2)
 
@@ -115,8 +129,7 @@ func decryptPKCS1v15(rand io.Reader, priv *PrivateKey, ciphertext []byte) (valid
 	// octets, followed by a 0, followed by the message.
 	//   lookingForIndex: 1 iff we are still looking for the zero.
 	//   index: the offset of the first zero byte.
-	var lookingForIndex, index int
-	lookingForIndex = 1
+	lookingForIndex := 1
 
 	for i := 2; i < len(em); i++ {
 		equals0 := subtle.ConstantTimeByteEq(em[i], 0)
@@ -129,8 +142,8 @@ func decryptPKCS1v15(rand io.Reader, priv *PrivateKey, ciphertext []byte) (valid
 	validPS := subtle.ConstantTimeLessOrEq(2+8, index)
 
 	valid = firstByteIsZero & secondByteIsTwo & (^lookingForIndex & 1) & validPS
-	msg = em[index+1:]
-	return
+	index = subtle.ConstantTimeSelect(valid, index+1, 0)
+	return valid, em, index, nil
 }
 
 // nonZeroRandomBytes fills the given slice with non-zero random octets.
diff --git a/src/pkg/crypto/rsa/pkcs1v15_test.go b/src/pkg/crypto/rsa/pkcs1v15_test.go
index 37c14d1d9..2dc5dbc2c 100644
--- a/src/pkg/crypto/rsa/pkcs1v15_test.go
+++ b/src/pkg/crypto/rsa/pkcs1v15_test.go
@@ -227,6 +227,26 @@ func TestUnpaddedSignature(t *testing.T) {
 	}
 }
 
+func TestShortSessionKey(t *testing.T) {
+	// This tests that attempting to decrypt a session key where the
+	// ciphertext is too small doesn't run outside the array bounds.
+	ciphertext, err := EncryptPKCS1v15(rand.Reader, &rsaPrivateKey.PublicKey, []byte{1})
+	if err != nil {
+		t.Fatalf("Failed to encrypt short message: %s", err)
+	}
+
+	var key [32]byte
+	if err := DecryptPKCS1v15SessionKey(nil, rsaPrivateKey, ciphertext, key[:]); err != nil {
+		t.Fatalf("Failed to decrypt short message: %s", err)
+	}
+
+	for _, v := range key {
+		if v != 0 {
+			t.Fatal("key was modified when ciphertext was invalid")
+		}
+	}
+}
+
 // In order to generate new test vectors you'll need the PEM form of this key:
 // -----BEGIN RSA PRIVATE KEY-----
 // MIIBOgIBAAJBALKZD0nEffqM1ACuak0bijtqE2QrI/KLADv7l3kK3ppMyCuLKoF0
diff --git a/src/pkg/crypto/subtle/constant_time.go b/src/pkg/crypto/subtle/constant_time.go
index de1a4e8c5..9c4b14a65 100644
--- a/src/pkg/crypto/subtle/constant_time.go
+++ b/src/pkg/crypto/subtle/constant_time.go
@@ -49,9 +49,14 @@ func ConstantTimeEq(x, y int32) int {
 	return int(z & 1)
 }
 
-// ConstantTimeCopy copies the contents of y into x iff v == 1. If v == 0, x is left unchanged.
-// Its behavior is undefined if v takes any other value.
+// ConstantTimeCopy copies the contents of y into x (a slice of equal length)
+// if v == 1. If v == 0, x is left unchanged. Its behavior is undefined if v
+// takes any other value.
 func ConstantTimeCopy(v int, x, y []byte) {
+	if len(x) != len(y) {
+		panic("subtle: slices have different lengths")
+	}
+
 	xmask := byte(v - 1)
 	ymask := byte(^(v - 1))
 	for i := 0; i < len(x); i++ {
diff --git a/src/pkg/net/dnsconfig_unix.go b/src/pkg/net/dnsconfig_unix.go
index af288253e..db45716f1 100644
--- a/src/pkg/net/dnsconfig_unix.go
+++ b/src/pkg/net/dnsconfig_unix.go
@@ -75,19 +75,19 @@ func dnsReadConfig(filename string) (*dnsConfig, error) {
 			for i := 1; i < len(f); i++ {
 				s := f[i]
 				switch {
-				case len(s) >= 6 && s[0:6] == "ndots:":
+				case hasPrefix(s, "ndots:"):
 					n, _, _ := dtoi(s, 6)
 					if n < 1 {
 						n = 1
 					}
 					conf.ndots = n
-				case len(s) >= 8 && s[0:8] == "timeout:":
+				case hasPrefix(s, "timeout:"):
 					n, _, _ := dtoi(s, 8)
 					if n < 1 {
 						n = 1
 					}
 					conf.timeout = n
-				case len(s) >= 8 && s[0:9] == "attempts:":
+				case hasPrefix(s, "attempts:"):
 					n, _, _ := dtoi(s, 9)
 					if n < 1 {
 						n = 1
@@ -103,3 +103,7 @@ func dnsReadConfig(filename string) (*dnsConfig, error) {
 
 	return conf, nil
 }
+
+func hasPrefix(s, prefix string) bool {
+	return len(s) >= len(prefix) && s[:len(prefix)] == prefix
+}
diff --git a/src/pkg/net/fd_unix.go b/src/pkg/net/fd_unix.go
index b82ecd11c..e22861abb 100644
--- a/src/pkg/net/fd_unix.go
+++ b/src/pkg/net/fd_unix.go
@@ -68,16 +68,19 @@ func (fd *netFD) name() string {
 	return fd.net + ":" + ls + "->" + rs
 }
 
-func (fd *netFD) connect(la, ra syscall.Sockaddr) error {
+func (fd *netFD) connect(la, ra syscall.Sockaddr, deadline time.Time) error {
 	// Do not need to call fd.writeLock here,
 	// because fd is not yet accessible to user,
 	// so no concurrent operations are possible.
-	if err := fd.pd.PrepareWrite(); err != nil {
-		return err
-	}
 	switch err := syscall.Connect(fd.sysfd, ra); err {
 	case syscall.EINPROGRESS, syscall.EALREADY, syscall.EINTR:
 	case nil, syscall.EISCONN:
+		if !deadline.IsZero() && deadline.Before(time.Now()) {
+			return errTimeout
+		}
+		if err := fd.init(); err != nil {
+			return err
+		}
 		return nil
 	case syscall.EINVAL:
 		// On Solaris we can see EINVAL if the socket has
@@ -92,6 +95,13 @@ func (fd *netFD) connect(la, ra syscall.Sockaddr) error {
 	default:
 		return err
 	}
+	if err := fd.init(); err != nil {
+		return err
+	}
+	if !deadline.IsZero() {
+		fd.setWriteDeadline(deadline)
+		defer fd.setWriteDeadline(noDeadline)
+	}
 	for {
 		// Performing multiple connect system calls on a
 		// non-blocking socket under Unix variants does not
diff --git a/src/pkg/net/fd_windows.go b/src/pkg/net/fd_windows.go
index a1f6bc5f8..d1129dccc 100644
--- a/src/pkg/net/fd_windows.go
+++ b/src/pkg/net/fd_windows.go
@@ -313,10 +313,17 @@ func (fd *netFD) setAddr(laddr, raddr Addr) {
 	runtime.SetFinalizer(fd, (*netFD).Close)
 }
 
-func (fd *netFD) connect(la, ra syscall.Sockaddr) error {
+func (fd *netFD) connect(la, ra syscall.Sockaddr, deadline time.Time) error {
 	// Do not need to call fd.writeLock here,
 	// because fd is not yet accessible to user,
 	// so no concurrent operations are possible.
+	if err := fd.init(); err != nil {
+		return err
+	}
+	if !deadline.IsZero() {
+		fd.setWriteDeadline(deadline)
+		defer fd.setWriteDeadline(noDeadline)
+	}
 	if !canUseConnectEx(fd.net) {
 		return syscall.Connect(fd.sysfd, ra)
 	}
diff --git a/src/pkg/net/sock_posix.go b/src/pkg/net/sock_posix.go
index a6ef874c9..c80c7d6a2 100644
--- a/src/pkg/net/sock_posix.go
+++ b/src/pkg/net/sock_posix.go
@@ -107,24 +107,18 @@ func (fd *netFD) dial(laddr, raddr sockaddr, deadline time.Time, toAddr func(sys
 			}
 		}
 	}
-	if err := fd.init(); err != nil {
-		return err
-	}
 	var rsa syscall.Sockaddr
 	if raddr != nil {
 		if rsa, err = raddr.sockaddr(fd.family); err != nil {
 			return err
-		} else if rsa != nil {
-			if !deadline.IsZero() {
-				fd.setWriteDeadline(deadline)
-			}
-			if err := fd.connect(lsa, rsa); err != nil {
-				return err
-			}
-			fd.isConnected = true
-			if !deadline.IsZero() {
-				fd.setWriteDeadline(noDeadline)
-			}
+		}
+		if err := fd.connect(lsa, rsa, deadline); err != nil {
+			return err
+		}
+		fd.isConnected = true
+	} else {
+		if err := fd.init(); err != nil {
+			return err
 		}
 	}
 	lsa, _ = syscall.Getsockname(fd.sysfd)
diff --git a/src/pkg/net/testdata/resolv.conf b/src/pkg/net/testdata/resolv.conf
index b5972e09c..3841bbf90 100644
--- a/src/pkg/net/testdata/resolv.conf
+++ b/src/pkg/net/testdata/resolv.conf
@@ -3,3 +3,4 @@
 domain Home
 nameserver 192.168.1.1
 options ndots:5 timeout:10 attempts:3 rotate
+options attempts 3
diff --git a/src/pkg/runtime/sys_windows_386.s b/src/pkg/runtime/sys_windows_386.s
index e0c0631cf..576831d2c 100644
--- a/src/pkg/runtime/sys_windows_386.s
+++ b/src/pkg/runtime/sys_windows_386.s
@@ -88,6 +88,10 @@ TEXT runtime·sigtramp(SB),NOSPLIT,$0-0
 
 	// fetch g
 	get_tls(DX)
+ 	CMPL	DX, $0
+ 	JNE	3(PC)
+ 	MOVL	$0, AX // continue
+ 	JMP	done
 	MOVL	m(DX), AX
 	CMPL	AX, $0
 	JNE	2(PC)
@@ -100,6 +104,7 @@ TEXT runtime·sigtramp(SB),NOSPLIT,$0-0
 	CALL	runtime·sighandler(SB)
 	// AX is set to report result back to Windows
 
+done:
 	// restore callee-saved registers
 	MOVL	24(SP), DI
 	MOVL	20(SP), SI
diff --git a/src/pkg/runtime/sys_windows_amd64.s b/src/pkg/runtime/sys_windows_amd64.s
index 94845903e..d161be6a5 100644
--- a/src/pkg/runtime/sys_windows_amd64.s
+++ b/src/pkg/runtime/sys_windows_amd64.s
@@ -120,6 +120,10 @@ TEXT runtime·sigtramp(SB),NOSPLIT,$0-0
 
 	// fetch g
 	get_tls(DX)
+ 	CMPQ	DX, $0
+ 	JNE	3(PC)
+ 	MOVQ	$0, AX // continue
+ 	JMP	done
 	MOVQ	m(DX), AX
 	CMPQ	AX, $0
 	JNE	2(PC)
@@ -132,6 +136,7 @@ TEXT runtime·sigtramp(SB),NOSPLIT,$0-0
 	CALL	runtime·sighandler(SB)
 	// AX is set to report result back to Windows
 
+done:
 	// restore registers as required for windows callback
 	MOVQ	24(SP), R15
 	MOVQ	32(SP), R14
diff --git a/src/pkg/runtime/traceback_arm.c b/src/pkg/runtime/traceback_arm.c
index d15244c2a..30f43d54c 100644
--- a/src/pkg/runtime/traceback_arm.c
+++ b/src/pkg/runtime/traceback_arm.c
@@ -128,9 +128,14 @@ runtime·gentraceback(uintptr pc0, uintptr sp0, uintptr lr0, G *gp, int32 skip,
 				frame.lr = *(uintptr*)frame.sp;
 			flr = runtime·findfunc(frame.lr);
 			if(flr == nil) {
-				runtime·printf("runtime: unexpected return pc for %s called from %p\n", runtime·funcname(f), frame.lr);
-				if(callback != nil)
+				// This happens if you get a profiling interrupt at just the wrong time.
+				// In that context it is okay to stop early.
+				// But if callback is set, we're doing a garbage collection and must
+				// get everything, so crash loudly.
+				if(callback != nil) {
+					runtime·printf("runtime: unexpected return pc for %s called from %p\n", runtime·funcname(f), frame.lr);
 					runtime·throw("unknown caller pc");
+				}
 			}
 		}
 
diff --git a/src/pkg/runtime/traceback_x86.c b/src/pkg/runtime/traceback_x86.c
index 851504f52..7359cfcc9 100644
--- a/src/pkg/runtime/traceback_x86.c
+++ b/src/pkg/runtime/traceback_x86.c
@@ -214,7 +214,7 @@ runtime·gentraceback(uintptr pc0, uintptr sp0, uintptr lr0, G *gp, int32 skip,
 		// the SP is two words lower than normal.
 		sparg = frame.sp;
 		if(wasnewproc)
-			sparg += 2*sizeof(uintreg);
+			sparg += 2*sizeof(uintptr);
 
 		// Determine frame's 'continuation PC', where it can continue.
 		// Normally this is the return address on the stack, but if sigpanic