Sync our regex code with upstream changes since last time we did this,
which was Tcl 8.5.11 (see commit 08fd6ff37f).
The only functional change here is to disbelieve that an octal escape is
three digits long if it would exceed \377. That's a bug fix, but it's
a minor one and could change the interpretation of working regexes, so
don't back-patch.
In addition to that, s/INFINITY/DUPINF/ to eliminate the risk of collisions
with <math.h>'s macro, and s/LOCAL/NOPROP/ because that also seems like
an unnecessarily collision-prone macro name.
There were some other cosmetic changes in their copy that I did not adopt,
notably a rather half-hearted attempt at renaming some of the C functions
in a more verbose style. (I'm not necessarily against the concept, but
renaming just a few functions in the package is not an improvement.)
These changes should generally improve correctness/maintainability.
A nice side benefit is that several kilobytes move from initialized
data to text segment, allowing them to be shared across processes and
probably reducing copy-on-write overhead while forking a new backend.
Unfortunately this doesn't seem to help libpq in the same way (at least
not when it's compiled with -fpic on x86_64), but we can hope the linker
at least collects all nominally-const data together even if it's not
actually part of the text segment.
Also, make pg_encname_tbl[] static in encnames.c, since there seems
no very good reason for any other code to use it; per a suggestion
from Wim Lewis, who independently submitted a patch that was mostly
a subset of this one.
Oskari Saarenmaa, with some editorialization by me
Per C standard, these are semantically the same thing; but saying NULL
when you mean NULL is good for readability.
Marti Raudsepp, per results of INRIA's Coccinelle.
was Tcl 8.4.8. The main changes are to remove the never-fully-implemented
code for multi-character collating elements, and to const-ify some stuff a
bit more fully. In combination with the recent security patch, this commit
brings us into line with Tcl 8.5.0.
Note that I didn't make any effort to duplicate a lot of cosmetic changes
that they made to bring their copy into line with their own style
guidelines, such as adding braces around single-line IF bodies. Most of
those we either had done already (such as ANSI-fication of function headers)
or there is no point because pgindent would undo the change anyway.
are shared with Tcl, since it's their code to begin with, and the patches
have been copied from Tcl 8.5.0. Problems:
CVE-2007-4769: Inadequate check on the range of backref numbers allows
crash due to out-of-bounds read.
CVE-2007-4772: Infinite loop in regex optimizer for pattern '($|^)*'.
CVE-2007-6067: Very slow optimizer cleanup for regex with a large NFA
representation, as well as crash if we encounter an out-of-memory condition
during NFA construction.
Part of the response to CVE-2007-6067 is to put a limit on the number of
states in the NFA representation of a regex. This seems needed even though
the within-the-code problems have been corrected, since otherwise the code
could try to use very large amounts of memory for a suitably-crafted regex,
leading to potential DOS by driving the system into swap, activating a kernel
OOM killer, etc.
Although there are certainly plenty of ways to drive the system into effective
DOS with poorly-written SQL queries, these problems seem worth treating as
security issues because many applications might accept regex search patterns
from untrustworthy sources.
Thanks to Will Drewry of Google for reporting these problems. Patches by Will
Drewry and Tom Lane.
Security: CVE-2007-4769, CVE-2007-4772, CVE-2007-6067
versions of gcc (I'm seeing it with Apple's gcc 4.0.1). I think the
reason we did not see this before was that the assert() macros in the
regex code were all no-ops till recently.
(extracted from Tcl 8.4.1 release, as Henry still hasn't got round to
making it a separate library). This solves a performance problem for
multibyte, as well as upgrading our regexp support to match recent Tcl
and nearly match recent Perl.
Tom Lane
Bruce Momjian
Magnus Hagander
PostgreSQL Daemon