bug303.go

     1  // run
     2  
     3  // Copyright 2010 The Go Authors. All rights reserved.
     4  // Use of this source code is governed by a BSD-style
     5  // license that can be found in the LICENSE file.
     6  
     7  // Issue 1011.  Removing either #1 or #3 avoided the crash at #2.
     8  
     9  package main
    10  
    11  import (
    12  	"io"
    13  	"strings"
    14  )
    15  
    16  func readU16BE(b []byte) uint16 {
    17  	b[0] = 0
    18  	b[1] = 1
    19  	return uint16(b[0])<<8 + uint16(b[1]) // #1
    20  	n := uint16(b[0])<<8 + uint16(b[1])
    21  	return n
    22  }
    23  
    24  func readStr(r io.Reader, b []byte) string {
    25  	n := readU16BE(b)
    26  	if int(n) > len(b) {
    27  		return "err: n>b"
    28  	}
    29  	io.ReadFull(r, b[0:n]) // #2
    30  	return string(b[0:n])  // #3
    31  	return "ok"
    32  }
    33  
    34  func main() {
    35  	br := strings.NewReader("abcd")
    36  	readStr(br, make([]byte, 256))
    37  }
    38
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