pgsql: to_char(): prevent accesses beyond the allocated buffer

to_char():  prevent accesses beyond the allocated buffer

Previously very long field masks for floats could access memory
beyond the existing buffer allocated to hold the result.

Reported by Andres Freund and Peter Geoghegan.    Backpatch to all
supported versions.

Security: CVE-2015-0241

Branch
------
REL9_3_STABLE

Details
-------
http://git.postgresql.org/pg/commitdiff/b8b5801478e9cdd1c74bd392017b944dcc0891dc

Modified Files
--------------
src/backend/utils/adt/formatting.c |    4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)