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| author | Cristian RodrÃguez <crrodriguez@opensuse.org> | 2016-02-17 14:02:04 (GMT) |
|---|---|---|
| committer | Brad King <brad.king@kitware.com> | 2016-02-19 14:44:59 (GMT) |
| commit | f23f18ab686faa0ce91486143469bb58753b0843 (patch) | |
| tree | 3400e6e9c38721e7825605834ab178dfcfeabc1e /Source/cmSystemTools.cxx | |
| parent | b13a74b35b17ecb44ec6ff552ecb1cbdac204361 (diff) | |
| download | CMake-f23f18ab686faa0ce91486143469bb58753b0843.zip CMake-f23f18ab686faa0ce91486143469bb58753b0843.tar.gz CMake-f23f18ab686faa0ce91486143469bb58753b0843.tar.bz2 | |
cmSystemTools: Avoid excess entropy consumption by RandomSeed (#15976)
Read `/dev/urandom` without buffering to avoid taking more than we need.
Diffstat (limited to 'Source/cmSystemTools.cxx')
| -rw-r--r-- | Source/cmSystemTools.cxx | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/Source/cmSystemTools.cxx b/Source/cmSystemTools.cxx index c9670fa..9af54bf 100644 --- a/Source/cmSystemTools.cxx +++ b/Source/cmSystemTools.cxx @@ -2183,8 +2183,10 @@ unsigned int cmSystemTools::RandomSeed() } seed; // Try using a real random source. - cmsys::ifstream fin("/dev/urandom"); - if(fin && fin.read(seed.bytes, sizeof(seed)) && + cmsys::ifstream fin; + fin.rdbuf()->pubsetbuf(0, 0); // Unbuffered read. + fin.open("/dev/urandom"); + if(fin.good() && fin.read(seed.bytes, sizeof(seed)) && fin.gcount() == sizeof(seed)) { return seed.integer; |