RFR [8043720] (smartcardio) Native memory should be handled more accurately

[Ivan Gerasimov]

One additional change:
In pcsc_multi2jstring() it is better to make sure the whole parsed 
buffer is null-terminates.

This way we can guarantee that in the following line we will not access 
memory outside the buffer:
                js = (*env)->NewStringUTF(env, tab[cnt]);

Would you please help review the updated webrev?
http://cr.openjdk.java.net/~igerasim/8043720/1/webrev/

Sincerely yours,
Ivan


On 27.05.2014 23:30, Ivan Gerasimov wrote:
> Hello!
>
> Here is a proposal to make some native memory manipulations in 
> src/share/native/sun/security/smartcardio/pcsc.c more accurate.
>
> 1)
> Add another argument to pcsc_multi2jstring() which will hold the size 
> of the character array to be parsed.
> In the function we make sure we do not access memory outside the array.
>
> 2)
> In pcsc_multi2jstring():
> There is a constant PCSCLITE_MAX_READERS_CONTEXTS == 16, which limits 
> number of cardreaders in the system.
> So we don't need to allocate the buffer with malloc.
>
> 3)
> In Java_sun_security_smartcardio_PCSC_SCardListReaders():
> The 'size' variable is initialized in the pcsc-lite API call to 
> SCardListReaders.
> Even though it should not be zero, if  SCardListReaders returned 
> SUCCESS, it's still a call of foreign function.
> Thus we better handle the case when size == 0.
>
> 4)
> Currently Java_sun_security_smartcardio_PCSC_SCardGetStatusChange is 
> always called with non-empty jReaderNames argument.
> However, it seems easy to make it more robust with a couple of checks 
> for the empty array of names.
>
> 5)
> In Java_sun_security_smartcardio_PCSC_SCardGetStatusChange, readers' 
> names are allocated with strdup() and later freed with free().
> If the program gets to cleanup upon an error, some of the names may 
> turn out be be never initialized, so free() can fail.
>
> Would you please help review the fix?
>
> BUGURL: https://bugs.openjdk.java.net/browse/JDK-8043720
> WEBREV: http://cr.openjdk.java.net/~igerasim/8043720/0/webrev/
>
> Sincerely yours,
> Ivan
>
>
>