Here's an updated patch. cryptlib.cpp already includes <osrng.h>, so
there's no need for the hack.
$ git diff cryptlib.cpp
diff --git a/cryptlib.cpp b/cryptlib.cpp
index a9ed290..228f18a 100644
--- a/cryptlib.cpp
+++ b/cryptlib.cpp
@@ -252,11 +252,9 @@ byte RandomNumberGenerator::GenerateByte()
word32 RandomNumberGenerator::GenerateWord32(word32 min, word32 max)
{
- word32 range = max-min;
+ word32 value, range = max-min;
const int maxBits = BitPrecision(range);
- word32 value;
-
do
{
GenerateBlock((byte *)&value, sizeof(value));
@@ -282,10 +280,10 @@ void
RandomNumberGenerator::GenerateIntoBufferedTransforma
FixedSizeSecBlock<byte, 256> buffer;
while (length)
{
- size_t len = UnsignedMin(buffer.size(), length);
- GenerateBlock(buffer, len);
- target.ChannelPut(channel, buffer, len);
- length -= len;
+ const size_t segmentLen = UnsignedMin(buffer.size(),
length);
+ OS_GenerateRandomBlock(false, buffer, segmentLen);
+ target.ChannelPut(channel, buffer, segmentLen);
+ length -= segmentLen;
}
}
On Wednesday, July 8, 2015 at 11:26:53 AM UTC-4, Jeffrey Walton wrote:
>
> Testing of RandomNumberGenerator::GenerateWord32 revealed a bug in
> GenerateBlock.
>
> GenerateBlock calls GenerateIntoBufferedTransformation.
> GenerateIntoBufferedTransformation, in turn, calls, GenerateBlock. Ad
> infinitum.
>
> This patch fixes the circularity by calling OS_GenerateRandomBlock using
> the OS's default entropy pool for userspace in a non-blocking mode.
>
> Another way to address t is to have GenerateIntoBufferedTransformation
> throw an Exception with type set to NOT_IMPLEMENTED. But I think that
> course will be less useful.
>
> Any comments or suggestions?
>
> **********
>
> $ cat cryptlib.diff
> diff --git a/cryptlib.cpp b/cryptlib.cpp
> index a9ed290..ad173e2 100644
> --- a/cryptlib.cpp
> +++ b/cryptlib.cpp
> @@ -277,13 +277,15 @@ void RandomNumberGenerator::DiscardBytes(size_t n)
> GenerateIntoBufferedTransformation(TheBitBucket(), DEFAULT_CHANNEL,
> n);
> }
>
> +// Avoid bringing in <osrng.h>, which depends on <cryptlib.h>
> +extern void OS_GenerateRandomBlock(bool, byte*, size_t);
> void
> RandomNumberGenerator::GenerateIntoBufferedTransformation(BufferedTransformation
>
> &target, const std::string &channel, lword length)
> {
> FixedSizeSecBlock<byte, 256> buffer;
> while (length)
> {
> size_t len = UnsignedMin(buffer.size(), length);
> - GenerateBlock(buffer, len);
> + OS_GenerateRandomBlock(false, buffer, len);
> target.ChannelPut(channel, buffer, len);
> length -= len;
> }
>
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