On Sep 27, 4:41 pm, David Irvine <[email protected]> wrote:
> Hi
>
> I am testing gcc 4.6 and found what appears to be a bug. If I use
> CryptoPP::AutoSeededX917RNG< CryptoPP::AES >
> g_srandom_number_generator;
> (any cypher fails)
>
> Then it's a segfault (see below)
>
> However switching to (which I do not want to do, or more likely
> cannot)
> CryptoPP::AutoSeededRandomPool g_srandom_number_generator;
>
> Is fine, if not as secure.
> ########################################################################
> System is Linux
> Linux di-ubuntu-64 3.0.0-11-generic #18-Ubuntu SMP Tue Sep 13 23:38:01
> UTC 2011 x86_64 x86_64 x86_64 GNU/Linux
> Ubuntu oneiric (development branch)
>
> I am not wishing to make too much of this as this is a beta release
> OS, but it seems more of a cryptopp issue I think. Is anyone else
> using ?
> gcc (Ubuntu/Linaro 4.6.1-9ubuntu3) 4.6.1
> Copyright (C) 2011 Free Software Foundation, Inc.
> This is free software; see the source for copying conditions. There
> is NO
> warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
> PURPOSE
>
> Segfault below
>
> #0 0x000000000071c3ad in
> CryptoPP::BufferedTransformation::ChannelPut2(std::string const&,
> unsigned char const*, unsigned long, int, bool)
> ()
> #1 0x00000000007b543e in
> CryptoPP::X917RNG::GenerateIntoBufferedTransformation(CryptoPP::BufferedTransformation&,
> std::string const&, unsigned long long) ()
> #2 0x000000000071c88e in
> CryptoPP::RandomNumberGenerator::GenerateBlock(unsigned char*,
> unsigned long) ()
> #3 0x00000000007b576b in
> CryptoPP::X917RNG::X917RNG(CryptoPP::BlockTransformation*, unsigned
> char const*, unsigned char const*) ()
> #4 0x0000000000743cc5 in
> CryptoPP::AutoSeededX917RNG<CryptoPP::Rijndael>::Reseed(unsigned char
> const*, unsigned long, unsigned char const*, unsigned char const*) ()
> #5 0x0000000000743ed8 in
> CryptoPP::AutoSeededX917RNG<CryptoPP::Rijndael>::Reseed(bool, unsigned
> char const*, unsigned long) ()
> #6 0x0000000000744000 in
> CryptoPP::AutoSeededX917RNG<CryptoPP::Rijndael>::AutoSeededX917RNG(bool,
> bool) ()
> #7 0x00000000006eddc0 in __static_initialization_and_destruction_0
> (__initialize_p=1, __priority=65535)
> at /home/dirvine/Devel/MaidSafe-Common/maidsafe_common_lib/src/
> maidsafe/common/crypto.cc:61
> #8 0x00000000006ede24 in _GLOBAL__sub_I_crypto.cc(void) ()
> at /home/dirvine/Devel/MaidSafe-Common/maidsafe_common_lib/src/
> maidsafe/common/crypto.cc:299AES/CTR IV custom increment
> #9 0x00000000007e9ded in __libc_csu_init ()
> #10 0x00007ffff70a02a0 in __libc_start_main (main=0x5f3114 <main(int,
> char**)>, argc=1, ubp_av=0x7fffffffe118,
> init=0x7e9d90 <__libc_csu_init>, fini=<optimized out>,
> rtld_fini=<optimized out>, stack_end=0x7fffffffe108) at libc-start.c:
> 185
> #11 0x00000000005f305d in _start ()
> (gdb) quit
I would guess that g_srandom_number_generator is in one compilation
unit, and the code using it is in another. Ie,
g_srandom_number_generator is in my_rng.cpp, and the code using it is
in my_key_gen.cpp. In this case, you would be violating C++'s static
non-local rules.
The fix is relatively easy. Offer a static/global function to serve up
a static local:
RandomNumberGenerator& GetRandomNumberGenerator()
{
static AutoSeededX917RNG< CryptoPP::AES > s_prng;
return s_prng;
}
Jeff
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