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zaptreesubs() was coded to unconditionally reset a capture subre's corresponding pmatch[] entry. However, in regexes without backrefs, that array is caller-supplied and might not have as many entries as the regex has capturing parens. So check the array length and do nothing if there is no corresponding entry, much as subset() does. Failure to check this resulted in a stack clobber in the case reported by Marko Kreen. This bug appears to have been latent in the regex library from the beginning. It was not exposed because find() called dissect() not cdissect(), and the dissect() code path didn't ever call zaptreesubs() (formerly zapmem()). When I unified dissect() and cdissect() in commit 4dd78bf37aa29d04b3f358b08c4a2fa43cf828e7, the problem was exposed. Now that I've seen this, I'm rather suspicious that we might need to back-patch it; but will refrain for now, for lack of evidence that the case can be hit in the previous coding.
PostgreSQL Database Management System ===================================== This directory contains the source code distribution of the PostgreSQL database management system. PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings. PostgreSQL has many language interfaces, many of which are listed here: http://www.postgresql.org/download See the file INSTALL for instructions on how to build and install PostgreSQL. That file also lists supported operating systems and hardware platforms and contains information regarding any other software packages that are required to build or run the PostgreSQL system. Changes between all PostgreSQL releases are recorded in the file HISTORY. Copyright and license information can be found in the file COPYRIGHT. A comprehensive documentation set is included in this distribution; it can be read as described in the installation instructions. The latest version of this software may be obtained at http://www.postgresql.org/download/. For more information look at our web site located at http://www.postgresql.org/.