#260 Reading from memory files depends upon uninitialized value read

[Jeffrey Sorensen]

sox_open_mem_read creates a file using fmemopen, and in the method is_seekable in formats.c, sox is calling
fstat(fileno((FILE*)ft->fp), &st);
this is failing with an error of bad file handle which is being ignored and leaving st in an uninitialized/undefined state.

From the NOTES section of man fmemopen:
There is no file descriptor associated with the file stream returned by
these functions (i.e., fileno(3) will return an error if called on the
returned stream).

This means that is_seekable can return an unpredictable result. fmemopen files do support seeking, so there is no specific harm here, although some tools that report uninitialized accesses trigger.

[Stefan Sauer]

Patch in https://sourceforge.net/p/sox/patches/109/

[Mans Rullgard]

Fixed.