From: Matt Corallo <git@bluematt.me>
Date: Tue, 30 Nov 2021 01:38:04 +0000 (+0000)
Subject: Check array lengths before passing them to C
X-Git-Tag: v0.0.103.1^2~12
X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=commitdiff_plain;h=490adeaa3273fe53040c11f415782977895d0be7;hp=490adeaa3273fe53040c11f415782977895d0be7;p=ldk-java

Check array lengths before passing them to C

When users pass a static-length array to C we currently CHECK its
length, asserting only if we are built in debug mode. In
production, we happily call JNI's `GetByteArrayRegion` with the
expected length, ignoring any errors. `GetByteArrayRegion`,
however, "THROWS ArrayIndexOutOfBoundsException: if one of the
indexes in the region is not valid.". While its somewhat unclear
what "THROWS" means in the context of a C API, it seems safe to
assume accessing return values after a "THROWS" condition is
undefined. Thus, we should ensure we check array lengths before
calling into C.

We do this here with a simple wrapper function added to
`org.ldk.util.InternalUtils` which checks an array is the correct
length before returning it.
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