postgresql/src/backend
Tom Lane 9bbf6f7341 Prevent regexp back-refs from sometimes matching when they shouldn't.
The recursion in cdissect() was careless about clearing match data
for capturing parentheses after rejecting a partial match.  This
could allow a later back-reference to succeed when by rights it
should fail for lack of a defined referent.

To fix, think a little more rigorously about what the contract
between different levels of cdissect's recursion needs to be.
With the right spec, we can fix this using fewer rather than more
resets of the match data; the key decision being that a failed
sub-match is now explicitly responsible for clearing any matches
it may have set.

There are enough other cross-checks and optimizations in the code
that it's not especially easy to exhibit this problem; usually, the
match will fail as-expected.  Plus, regexps that are even potentially
vulnerable are most likely user errors, since there's just not much
point in writing a back-ref that doesn't always have a referent.
These facts perhaps explain why the issue hasn't been detected,
even though it's almost certainly a couple of decades old.

Discussion: https://postgr.es/m/151435.1629733387@sss.pgh.pa.us
2021-08-23 17:41:07 -04:00
..
access Avoid creating archive status ".ready" files too early 2021-08-23 15:50:35 -04:00
bootstrap Fix bogus assertion in BootstrapModeMain(). 2021-08-09 08:28:53 -07:00
catalog Prevent ALTER TYPE/DOMAIN/OPERATOR from changing extension membership. 2021-08-17 14:29:22 -04:00
commands Prevent ALTER TYPE/DOMAIN/OPERATOR from changing extension membership. 2021-08-17 14:29:22 -04:00
executor Improve error messages about misuse of SELECT INTO. 2021-08-21 10:22:14 -04:00
foreign Update copyright for 2021 2021-01-02 13:06:25 -05:00
jit Clarify some comments making use of leetspeak term "up2date" 2021-07-28 10:31:24 +09:00
lib Fix typo in comment 2021-04-20 14:35:16 +02:00
libpq Set type identifier on BIO 2021-08-17 14:30:01 +02:00
main process startup: Centralize pgwin32_signal_initialize() calls. 2021-08-05 12:36:06 -07:00
nodes Check the size in COPY_POINTER_FIELD 2021-08-08 18:46:34 +02:00
optimizer Allow parallel DISTINCT 2021-08-22 23:31:16 +12:00
parser Avoid trying to lock OLD/NEW in a rule with FOR UPDATE. 2021-08-19 12:12:35 -04:00
partitioning Allow ordered partition scans in more cases 2021-08-03 12:25:52 +12:00
po Translation updates 2021-06-21 12:33:50 +02:00
port Make EXEC_BACKEND more convenient on macOS. 2021-08-13 11:09:00 +12:00
postmaster Avoid creating archive status ".ready" files too early 2021-08-23 15:50:35 -04:00
regex Prevent regexp back-refs from sometimes matching when they shouldn't. 2021-08-23 17:41:07 -04:00
replication Avoid creating archive status ".ready" files too early 2021-08-23 15:50:35 -04:00
rewrite Use l*_node() family of functions where appropriate 2021-07-19 08:20:24 +02:00
snowball Update snowball 2021-02-19 08:10:15 +01:00
statistics Error message refactoring 2021-06-27 09:41:16 +02:00
storage Un-break s_lock_test. 2021-08-13 14:42:27 -04:00
tcop process startup: Always call Init[Auxiliary]Process() before BaseInit(). 2021-08-05 15:36:59 -07:00
tsearch Improve various places that double the size of a buffer 2021-07-01 15:29:06 +12:00
utils Improve defaults shown in postgresql.conf.sample and pg_settings 2021-08-23 12:33:38 -04:00
.gitignore Add .gitignore entries for AIX-specific intermediate build artifacts. 2015-07-08 20:44:22 -04:00
common.mk Remove PARTIAL_LINKING build mode. 2018-03-30 17:33:04 -07:00
Makefile Use sort_template.h for qsort_tuple() and qsort_ssup(). 2021-03-03 17:02:32 +13:00
nls.mk Translation updates 2021-05-10 14:36:21 +02:00