Bug #2383: windows - calling FreeEnvironmentStrings on envarea invalidates memory in use

• Status: Rejected
• Assignee: -
• ruby -v: ruby 1.9.1p0 (2009-01-30 revision 21907) [i386-mswin32]

[mosbessus (Mos Bessus)]

=begin
In win32.c, in rb_w32_getenv, the code calls FreeEnvironmentStrings(envarea). By doing this, it invalidates memory that's currently in use.

see env_fetch in hash.c:

...
env = getenv(nam);
...
if (ENVMATCH(nam, PATH_ENV) && !rb_env_path_tainted())
return rb_str_new2(env);

and in rb_env_path_tainted:

 if (path_tainted < 0) {
path_tainted_p(getenv(PATH_ENV));
 }

the getenv call in rb_env_path_tainted frees envarea, but there's still an outstanding reference to memory in envarea: env, from env_fetch. Then we try to create a new string from env and dereference freed memory.

The repro is very simple:

print "#{ENV["path"]}\n"

run this under the debugger with pageheap on.
=end

[ujihisa (Tatsuhiro Ujihisa)]

• Status changed from Open to Assigned
• Assignee set to usa (Usaku NAKAMURA)

=begin

=end

[usa (Usaku NAKAMURA)]

• Status changed from Assigned to Open
• Assignee deleted (usa (Usaku NAKAMURA))

=begin
See the definition of getenv in posix.
This is not a problem of Windows but a bug of the main body of ruby in clearness.
=end

[jeremyevans0 (Jeremy Evans)]

• Description updated (diff)
• Status changed from Open to Rejected