upstream/mercurial-mirror Files · contrib/fuzz/pyutil.cc

dirs: resolve fuzzer OOM situation by disallowing deep directory hierarchies...

dirs: resolve fuzzer OOM situation by disallowing deep directory hierarchies It seems like 2048 directories ought to be enough for any reasonable use of Mercurial? A previous version of this patch scanned for slashes before any allocations occurred. That approach is slower than this in the happy path, but much faster than this in the case that too many slashes are encountered. We may want to revisit it in the future using memchr() so it'll be well-optimized by the libc we're using. .. bc: Mercurial will now defend against OOMs by refusing to operate on paths with 2048 or more components. This means that _extremely_ deep path hierarchies will be rejected, but we anticipate nobody is using hierarchies this deep. Differential Revision: https://phab.mercurial-scm.org/D7411

Augie Fackler - - Load All Authors

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             pyutil.cc
        
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      #include "pyutil.h"

      #include <string>

      namespace contrib

      {

      static char cpypath[8192] = "\0";

      static PyObject *mainmod;

      static PyObject *globals;

      /* TODO: use Python 3 for this fuzzing? */

      PyMODINIT_FUNC initparsers(void);

      void initpy(const char *cselfpath)

      {

      	const std::string subdir = "/sanpy/lib/python2.7";

      	/* HACK ALERT: we need a full Python installation built without

      	   pymalloc and with ASAN, so we dump one in

      	   $OUT/sanpy/lib/python2.7. This helps us wire that up. */

      	std::string selfpath(cselfpath);

      	std::string pypath;

      	auto pos = selfpath.rfind("/");

      	if (pos == std::string::npos) {

      		char wd[8192];

      		getcwd(wd, 8192);

      		pypath = std::string(wd) + subdir;

      	} else {

      		pypath = selfpath.substr(0, pos) + subdir;

      	}

      	strncpy(cpypath, pypath.c_str(), pypath.size());

      	setenv("PYTHONPATH", cpypath, 1);

      	setenv("PYTHONNOUSERSITE", "1", 1);

      	/* prevent Python from looking up users in the fuzz environment */

      	setenv("PYTHONUSERBASE", cpypath, 1);

      	Py_SetPythonHome(cpypath);

      	Py_InitializeEx(0);

      	mainmod = PyImport_AddModule("__main__");

      	globals = PyModule_GetDict(mainmod);

      	initparsers();

      }

      PyObject *pyglobals()

      {

      	return globals;

      }

      } // namespace contrib

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				#include "pyutil.h"

				#include <string>

				namespace contrib
				{

				static char cpypath[8192] = "\0";

				static PyObject *mainmod;
				static PyObject *globals;

				/* TODO: use Python 3 for this fuzzing? */
				PyMODINIT_FUNC initparsers(void);

				void initpy(const char *cselfpath)
				{
				const std::string subdir = "/sanpy/lib/python2.7";
				/* HACK ALERT: we need a full Python installation built without
				pymalloc and with ASAN, so we dump one in
				$OUT/sanpy/lib/python2.7. This helps us wire that up. */
				std::string selfpath(cselfpath);
				std::string pypath;
				auto pos = selfpath.rfind("/");
				if (pos == std::string::npos) {
				char wd[8192];
				getcwd(wd, 8192);
				pypath = std::string(wd) + subdir;
				} else {
				pypath = selfpath.substr(0, pos) + subdir;
				}
				strncpy(cpypath, pypath.c_str(), pypath.size());
				setenv("PYTHONPATH", cpypath, 1);
				setenv("PYTHONNOUSERSITE", "1", 1);
				/* prevent Python from looking up users in the fuzz environment */
				setenv("PYTHONUSERBASE", cpypath, 1);
				Py_SetPythonHome(cpypath);
				Py_InitializeEx(0);
				mainmod = PyImport_AddModule("__main__");
				globals = PyModule_GetDict(mainmod);
				initparsers();
				}

				PyObject *pyglobals()
				{
				return globals;
				}

				} // namespace contrib