Hi Artem,
The specific fix looks fine, but there are many other calls to
getLength() in DerInputStream that subsequently initialize an array with
the return value, and could also cause the same issue. It seems to me
that a better fix would be to pass a flag to the getLength method (or
create a new method) and if the flag is true, throw an IOException if an
indefinite length encoding is used (instead of returning -1). Then, for
the encodings where it is illegal to use the indefinite-length method,
change the code to call the method with the flag set to true.
--Sean
On 01/30/2014 03:47 AM, Artem Smotrakov wrote:
Please review this fix for 9:
https://bugs.openjdk.java.net/browse/JDK-8028591
http://cr.openjdk.java.net/~asmotrak/8028591/webrev.00/
<http://cr.openjdk.java.net/%7Easmotrak/8028591/webrev.00/>
getLength() method is used to get a length of bit string. The method can
return a negative value that means indefinite-length encoding that is
not allowed in DER. Currently a negative value is not checked. As a
result, NegativeArraySizeException can occur.
I added the following checks in
sun.security.util.DerInputStream.getUnalignedBitString() method:
1. IOException is thrown if getLength() method returns a negative value.
2. Empty BitArray is returned if getLength() method returns zero.
I think that an empty bit string should be encoded as "03 01 00" in DER.
I am not sure, but probably "03 00" is valid one as well. I tried both
ones with OpenSSL asn1parse, and both ones were parsed successfully:
hexdump -C emtpy_bit_string_1
00000000 03 01 00 |...|
00000003
openssl asn1parse -inform der -in emtpy_bit_string_1
0:d=0 hl=2 l= 1 prim: BIT STRING
hexdump -C emtpy_bit_string_2
00000000 03 00 |..|
00000002
openssl asn1parse -inform der -in emtpy_bit_string_2
0:d=0 hl=2 l= 0 prim: BIT STRING
3. IOException is thrown if number of calculated valid bits is negative.
Added a test case for
test/java/security/cert/X509Certificate/X509BadCertificate.java
(bad-cert-2.pem is corrupted self-signed certificate). Tested with
available regression, SQE and JCK tests.
Artem
