UNIX BUILD NOTES¶
Some notes on how to build twister in Unix.
To Build¶
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Dependencies¶
Library Purpose Description ------- ------- ----------- libssl SSL Support Secure communications libdb4.8 Berkeley DB Blockchain & wallet storage libboost Boost C++ Library
IPv6 support may be disabled by setting:
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Licenses of statically linked libraries: Berkeley DB New BSD license with additional requirement that linked software must be free open source Boost MIT-like license
- Versions used in this release:
- GCC 4.3.3
- OpenSSL 1.0.1c
- Berkeley DB 4.8.30.NC
- Boost 1.37
Dependency Build Instructions: Ubuntu & Debian¶
Build requirements:
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for Ubuntu 12.04:
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db4.8 packages are available here.
Ubuntu precise has packages for libdb5.1-dev and libdb5.1++-dev, but using these will break binary wallet compatibility, and is not recommended.
for other Ubuntu & Debian:
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(If using Boost 1.37, append -mt to the boost libraries in the makefile)
Dependency Build Instructions: Gentoo¶
Note: If you just want to install bitcoind on Gentoo, you can add the Bitcoin overlay and use your package manager:
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Take the following steps to build (no UPnP support):
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Notes¶
The release is built with GCC and then "strip bitcoind" to strip the debug symbols, which reduces the executable size by about 90%.
Berkeley DB¶
You need Berkeley DB 4.8. If you have to build Berkeley DB yourself:
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Boost¶
If you need to build Boost yourself:
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Security¶
To help make your bitcoin installation more secure by making certain attacks impossible to exploit even if a vulnerability is found, you can take the following measures:
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Position Independent Executable Build position independent code to take advantage of Address Space Layout Randomization offered by some kernels. An attacker who is able to cause execution of code at an arbitrary memory location is thwarted if he doesn't know where anything useful is located. The stack and heap are randomly located by default but this allows the code section to be randomly located as well.
On an Amd64 processor where a library was not compiled with -fPIC, this will cause an error such as: "relocation R_X86_64_32 against `......' can not be used when making a shared object;"
To build with PIE, use:
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make -f makefile.unix ... -e PIE=1
To test that you have built PIE executable, install scanelf, part of paxutils, and use:
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scanelf -e ./bitcoin
The output should contain: TYPE ET_DYN
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Non-executable Stack If the stack is executable then trivial stack based buffer overflow exploits are possible if vulnerable buffers are found. By default, bitcoin should be built with a non-executable stack but if one of the libraries it uses asks for an executable stack or someone makes a mistake and uses a compiler extension which requires an executable stack, it will silently build an executable without the non-executable stack protection.
To verify that the stack is non-executable after compiling use:
scanelf -e ./bitcoin
the output should contain: STK/REL/PTL RW- R-- RW-
The STK RW- means that the stack is readable and writeable but not executable.