5 Commits (c590e514a90ddc9237a3438efb05be074d43452b)

Author	SHA1	Message	Date
Michael Paquier	27d3844418	pageinspect: Add more sanity checks to prevent out-of-bound reads ... A couple of code paths use the special area on the page passed by the function caller, expecting to find some data in it. However, feeding an incorrect page can lead to out-of-bound reads when trying to access the page special area (like a heap page that has no special area, leading PageGetSpecialPointer() to grab a pointer outside the allocated page). The functions used for hash and btree indexes have some protection already against that, while some other functions using a relation OID as argument would make sure that the access method involved is correct, but functions taking in input a raw page without knowing the relation the page is attached to would run into problems. This commit improves the set of checks used in the code paths of BRIN, btree (including one check if a leaf page is found with a non-zero level), GIN and GiST to verify that the page given in input has a special area size that fits with each access method, which is done though PageGetSpecialSize(), becore calling PageGetSpecialPointer(). The scope of the checks done is limited to work with pages that one would pass after getting a block with get_raw_page(), as it is possible to craft byteas that could bypass existing code paths. Having too many checks would also impact the usability of pageinspect, as the existing code is very useful to look at the content details in a corrupted page, so the focus is really to avoid out-of-bound reads as this is never a good thing even with functions whose execution is limited to superusers. The safest approach could be to rework the functions so as these fetch a block using a relation OID and a block number, but there are also cases where using a raw page is useful. Tests are added to cover all the code paths that needed such checks, and an error message for hash indexes is reworded to fit better with what this commit adds. Reported-By: Alexander Lakhin Author: Julien Rouhaud, Michael Paquier Discussion: https://postgr.es/m/16527-ef7606186f0610a1@postgresql.org Discussion: https://postgr.es/m/561e187b-3549-c8d5-03f5-525c14e65bd0@postgrespro.ru Backpatch-through: 10	4 years ago
Michael Paquier	b61e6214cf	pageinspect: Fix handling of page sizes and AM types ... This commit fixes a set of issues related to the use of the SQL functions in this module when the caller is able to pass down raw page data as input argument: - The page size check was fuzzy in a couple of places, sometimes looking after only a sub-range, but what we are looking for is an exact match on BLCKSZ. After considering a few options here, I have settled down to do a generalization of get_page_from_raw(). Most of the SQL functions already used that, and this is not strictly required if not accessing an 8-byte-wide value from a raw page, but this feels safer in the long run for alignment-picky environment, particularly if a code path begins to access such values. This also reduces the number of strings that need to be translated. - The BRIN function brin_page_items() uses a Relation but it did not check the access method of the opened index, potentially leading to crashes. All the other functions in need of a Relation already did that. - Some code paths could fail on elog(), but we should to use ereport() for failures that can be triggered by the user. Tests are added to stress all the cases that are fixed as of this commit, with some junk raw pages (\set VERBOSITY ensures that this works across all page sizes) and unexpected index types when functions open relations. Author: Michael Paquier, Justin Prysby Discussion: https://postgr.es/m/20220218030020.GA1137@telsasoft.com Backpatch-through: 10	4 years ago
Heikki Linnakangas	5abca4b1cd	Fix test failure with wal_level=minimal. ... The newly-added gist pageinspect test prints the LSNs of GiST pages, expecting them all to be 1 (GistBuildLSN). But with wal_level=minimal, they got updated by the whole-relation WAL-logging at commit. Fix by wrapping the problematic tests in the same transaction with the CREATE INDEX. Per buildfarm failure on thorntail. Discussion: https://www.postgresql.org/message-id/3B4F97E5-40FB-4142-8CAA-B301CDFBF982%40iki.fi	5 years ago
Heikki Linnakangas	6ecaaf810b	Fix portability issues in the new gist pageinspect test. ... 1. The raw bytea representation of the point-type keys used in the test depends on endianess. Remove the raw key_data column from the test. 2. The items stored on non-leftmost gist page depends on how many items git on the other pages. This showed up as a failure on 32-bit i386 systems. To fix, only test the gist_page_items() function on the leftmost leaf page. Per Andrey Borodin and the buildfarm. Discussion: https://www.postgresql.org/message-id/9FCEC1DC-86FB-4A57-88EF-DD13663B36AF%40yandex-team.ru	5 years ago
Heikki Linnakangas	756ab29124	Add functions to 'pageinspect' to inspect GiST indexes. ... Author: Andrey Borodin and me Discussion: https://www.postgresql.org/message-id/3E4F9093-A1B5-4DF8-A292-0B48692E3954%40yandex-team.ru	5 years ago