cmd/asm: improve DATA size operand validation

Prior to this change, DATA instructions accepted
the values 1, 2, 4, and 8 as sizes.
The acceptable sizes were further restricted
to 4 and 8 for float constants.

This was both too restrictive and not restrictive enough:
string constants may reasonably have any length,
and address constants should really only accept pointer-length sizes.

Fixes #30269

Change-Id: I06e44ecdf5909eca7b19553861aec1fa39655c2b
Reviewed-on: https://go-review.googlesource.com/c/163747
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

diff --git a/src/cmd/asm/internal/asm/asm.go b/src/cmd/asm/internal/asm/asm.go
index 5da64f135a84a76486fc1903907f799efa924d18..3d99af6889388428a617092fca3aa1895343225c 100644 (file)
--- a/src/cmd/asm/internal/asm/asm.go
+++ b/src/cmd/asm/internal/asm/asm.go
@@ -7,6 +7,7 @@ package asm
 import (
        "bytes"
        "fmt"
+       "strconv"
        "text/scanner"
 
        "cmd/asm/internal/arch"
@@ -200,7 +201,11 @@ func (p *Parser) asmData(operands [][]lex.Token) {
                p.errorf("expect /size for DATA argument")
                return
        }
-       scale := p.parseScale(op[n-1].String())
+       szop := op[n-1].String()
+       sz, err := strconv.Atoi(szop)
+       if err != nil {
+               p.errorf("bad size for DATA argument: %q", szop)
+       }
        op = op[:n-2]
        nameAddr := p.address(op)
        if !p.validSymbol("DATA", &nameAddr, true) {
@@ -223,24 +228,33 @@ func (p *Parser) asmData(operands [][]lex.Token) {
                p.errorf("overlapping DATA entry for %s", name)
                return
        }
-       p.dataAddr[name] = nameAddr.Offset + int64(scale)
+       p.dataAddr[name] = nameAddr.Offset + int64(sz)
 
        switch valueAddr.Type {
        case obj.TYPE_CONST:
-               nameAddr.Sym.WriteInt(p.ctxt, nameAddr.Offset, int(scale), valueAddr.Offset)
+               switch sz {
+               case 1, 2, 4, 8:
+                       nameAddr.Sym.WriteInt(p.ctxt, nameAddr.Offset, int(sz), valueAddr.Offset)
+               default:
+                       p.errorf("bad int size for DATA argument: %d", sz)
+               }
        case obj.TYPE_FCONST:
-               switch scale {
+               switch sz {
                case 4:
                        nameAddr.Sym.WriteFloat32(p.ctxt, nameAddr.Offset, float32(valueAddr.Val.(float64)))
                case 8:
                        nameAddr.Sym.WriteFloat64(p.ctxt, nameAddr.Offset, valueAddr.Val.(float64))
                default:
-                       panic("bad float scale")
+                       p.errorf("bad float size for DATA argument: %d", sz)
                }
        case obj.TYPE_SCONST:
-               nameAddr.Sym.WriteString(p.ctxt, nameAddr.Offset, int(scale), valueAddr.Val.(string))
+               nameAddr.Sym.WriteString(p.ctxt, nameAddr.Offset, int(sz), valueAddr.Val.(string))
        case obj.TYPE_ADDR:
-               nameAddr.Sym.WriteAddr(p.ctxt, nameAddr.Offset, int(scale), valueAddr.Sym, valueAddr.Offset)
+               if sz == p.arch.PtrSize {
+                       nameAddr.Sym.WriteAddr(p.ctxt, nameAddr.Offset, int(sz), valueAddr.Sym, valueAddr.Offset)
+               } else {
+                       p.errorf("bad addr size for DATA argument: %d", sz)
+               }
        }
 }
 

diff --git a/src/cmd/asm/internal/asm/pseudo_test.go b/src/cmd/asm/internal/asm/pseudo_test.go
index 52c98b4056340036f828a5c4d6ddf591fc31703f..100bef91cfd79cd9f5105214a8f4c6f3127d47e2 100644 (file)
--- a/src/cmd/asm/internal/asm/pseudo_test.go
+++ b/src/cmd/asm/internal/asm/pseudo_test.go
@@ -43,6 +43,13 @@ func TestErroneous(t *testing.T) {
                {"DATA", "0", "expect two operands for DATA"},
                {"DATA", "(0), 1", "expect /size for DATA argument"},
                {"DATA", "@B(SB)/4,0", "expected '(', found B"}, // Issue 23580.
+               {"DATA", "·A(SB)/4,0", "DATA value must be an immediate constant or address"},
+               {"DATA", "·B(SB)/4,$0", ""},
+               {"DATA", "·C(SB)/5,$0", "bad int size for DATA argument: 5"},
+               {"DATA", "·D(SB)/5,$0.0", "bad float size for DATA argument: 5"},
+               {"DATA", "·E(SB)/4,$·A(SB)", "bad addr size for DATA argument: 4"},
+               {"DATA", "·F(SB)/8,$·A(SB)", ""},
+               {"DATA", "·G(SB)/5,$\"abcde\"", ""},
                {"GLOBL", "", "expect two or three operands for GLOBL"},
                {"GLOBL", "0,1", "GLOBL symbol \"<erroneous symbol>\" must be a symbol(SB)"},
                {"GLOBL", "@B(SB), 0", "expected '(', found B"}, // Issue 23580.