RFR(XS) 8129897: Old verifier fails to reject erroneous cast from boolean to byte
harold.seigel at oracle.com
Wed Jul 22 15:06:11 UTC 2015
Thanks for the review!
I updated lines 2256- 2261 in a new webrev:
Here are the new lines:
2256 case 'B': /* array of bytes or booleans */
2257 if (top_type != MAKE_FULLINFO(ITEM_Byte, 1, 0) &&
2258 top_type != MAKE_FULLINFO(ITEM_Boolean, 1, 0))
2260 "Expecting to find array of bytes or Booleans on stack");
File jdk/src/java.base/share/native/libverify/opcodes.in_out defines the
first operand for opcodes baload and bastore as [B. But, according to
the JVM Spec, the first operand for these bytecodes can be either [B or
[Z. This code checks that the opcodes, that opcodes.in_out says expect
[B, do not throw VerifyError if their actual operand is either [B or
[Z. Opcodes baload and bastore are the only opcodes in opcodes.in_out
with [B operands, and that's unlikely to change.
I removed "case 'Z': because there are no [Z operands for any opcodes in
On 7/21/2015 7:44 PM, David Holmes wrote:
> Hi Harold,
> On 22/07/2015 6:21 AM, harold seigel wrote:
>> Please review this small change to fix bug 8129897. The old verifier
>> treats arrays of Booleans as arrays of bytes, allowing assignability
>> between them. This fix distinguishes between arrays of Booleans and
>> arrays of bytes and so disallows assignability between them. Additional
>> changes were needed to make sure operands to baload and similar opcodes
>> could still be either Boolean or byte arrays.
>> Open webrev: http://cr.openjdk.java.net/~hseigel/bug_8129897/
> Seems reasonable. Only query I have was why you didn't split this:
> 2256 case 'B': case 'Z': /* array of bytes or
> booleans */
> 2257 if (top_type != MAKE_FULLINFO(ITEM_Byte,
> 1, 0) &&
> 2258 top_type !=
> MAKE_FULLINFO(ITEM_Boolean, 1, 0))
> 2259 CCerror(context,
> 2260 "Expecting to find array of
> bytes or Booleans on stack");
> 2261 break;
> into two distinct cases?
>> JBS Bug: https://bugs.openjdk.java.net/browse/JDK-8129897
>> The fix was tested with JCK Lang and VM tests, the UTE quick and split
>> verifier tests, and the hotspot, and JDK vm, java/io, java/lang, and
>> java/util JTreg tests.
>> This scenario will be tested by JCK-9. So no regression test was
>> included in this webrev.
>> Thanks, Harold
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