Prevent port/snprintf() from overflowing its local fixed-size
buffer and pad to the desired number of digits with zeros, even
if the precision is beyond the ability of the native sprintf().
port/snprintf() is only used on systems that lack a native
snprintf().
Reported by Bruce Momjian. Patch by Tom Lane. Backpatch to all
supported versions.
Security: CVE-2015-0242
Since C99, it's been standard for printf and friends to accept a "z" size
modifier, meaning "whatever size size_t has". Up to now we've generally
dealt with printing size_t values by explicitly casting them to unsigned
long and using the "l" modifier; but this is really the wrong thing on
platforms where pointers are wider than longs (such as Win64). So let's
start using "z" instead. To ensure we can do that on all platforms, teach
src/port/snprintf.c to understand "z", and add a configure test to force
use of that implementation when the platform's version doesn't handle "z".
Having done that, modify a bunch of places that were using the
unsigned-long hack to use "z" instead. This patch doesn't pretend to have
gotten everyplace that could benefit, but it catches many of them. I made
an effort in particular to ensure that all uses of the same error message
text were updated together, so as not to increase the number of
translatable strings.
It's possible that this change will result in format-string warnings from
pre-C99 compilers. We might have to reconsider if there are any popular
compilers that will warn about this; but let's start by seeing what the
buildfarm thinks.
Andres Freund, with a little additional work by me
value for a precision is negative, act as though precision weren't
specified at all, that is the whole .* part of the format spec should
be ignored. Our previous coding took it as .0 which is certainly
wrong. Per report from Kris Jurka and local testing.
Possibly this should be back-patched, but it would be good to get
some more testing first; in any case there are no known cases where
there's really a problem on the backend side.
incorrect implementation of argument reordering, arbitrary limit of output
size for sprintf and fprintf, willingness to access more bytes than "%.Ns"
specification allows, wrong formatting of LONGLONG_MIN, various field-padding
bugs and omissions. I believe it now accurately implements a subset of
the Single Unix Spec requirements (remaining unimplemented features are
documented, too). Bruce Momjian and Tom Lane.
The first rule of portability for us is 'thou shalt have no other gods
before c.h', and a whole lot of these files were either not including
c.h at all, or including random system headers beforehand, either of
which sins can mess up largefile support nicely. Once you have
included c.h, there is no need to re-include what it includes, either.
Document use of macros for pg_printf functions.
Bump major versions of all interfaces to handle movement of get_progname
from libpq to libpgport in 8.0, and probably other libpgport changes in 8.1.
+ # Determine if printf supports %1$ argument selection, e.g. %5$ selects
+ # the fifth argument after the printf print string.
+ # This is not in the C99 standard, but in the Single Unix Specification (SUS).
+ # It is used in our langauge translation strings.
Nicolai Tufar with configure changes by Bruce.