[jira] [Commented] (HADOOP-12869) CryptoInputStream#read() may return incorrect result

["Dapeng Sun (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HADOOP-12869?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15177100#comment-15177100 ] 

Dapeng Sun commented on HADOOP-12869:
-------------------------------------

Added [~dian.fu] who investigated this issue together with me.

> CryptoInputStream#read() may return incorrect result
> ----------------------------------------------------
>
>                 Key: HADOOP-12869
>                 URL: https://issues.apache.org/jira/browse/HADOOP-12869
>             Project: Hadoop Common
>          Issue Type: Bug
>          Components: security
>    Affects Versions: 2.7.2, 3.0.0
>            Reporter: Dapeng Sun
>            Assignee: Dapeng Sun
>            Priority: Critical
>         Attachments: HADOOP-12869.001.patch
>
>
> Here is the comment of {{FilterInputStream#read()}}:
> {noformat}
>     /**
>      * Reads the next byte of data from this input stream. The value
>      * byte is returned as an <code>int</code> in the range
>      * <code>0</code> to <code>255</code>. If no byte is available
>      * because the end of the stream has been reached, the value
>      * <code>-1</code> is returned. This method blocks until input data
>      * is available, the end of the stream is detected, or an exception
>      * is thrown.
>      * <p>
>      * This method
>      * simply performs <code>in.read()</code> and returns the result.
>      *
>      * @return     the next byte of data, or <code>-1</code> if the end of the
>      *             stream is reached.
>      * @exception  IOException  if an I/O error occurs.
>      * @see        java.io.FilterInputStream#in
>      */
>     public int read() throws IOException {
>         return in.read();
>     }
> {noformat}
> Here is the implementation of {{CryptoInputStream#read()}} in Hadoop Common:
> {noformat}
> @Override
> public int read() throws IOException {
>   return (read(oneByteBuf, 0, 1) == -1) ? -1 : (oneByteBuf[0] & 0xff);		
> }
> {noformat}
> The return value of {{read(oneByteBuf, 0, 1)}} maybe 1, -1 and 0:
> For {{1}}: we should return the content of {{oneByteBuf}}
> For {{-1}}: we should return {{-1}} to stand for the end of stream
> For {{0}}: it means we didn't get decryption data back and it is not the end of the stream, we should continue to decrypt the stream. But it return {{0}} on {{read()}} in current implementation, it means the decrypted content is {{0}} and it is incorrect.



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