From b0f7dd915bca6243f3daf52a81b8d0682a38ee3b Mon Sep 17 00:00:00 2001 From: Alvaro Herrera Date: Wed, 8 Nov 2023 18:44:54 +0100 Subject: [PATCH] Check stack depth in new recursive functions Commit b0e96f311985 introduced a bunch of recursive functions, but failed to make them check for stack depth. This can cause the backend to crash when operating on inheritance hierarchies several thousands deep. Protect the code by adding the missing stack depth checks. Reported-by: Alexander Lakhin Discussion: https://postgr.es/m/b2ac2392-9727-5f76-e890-721ac80c1615@gmail.com --- src/backend/commands/tablecmds.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c index 416a98e7cef..e456ccd767e 100644 --- a/src/backend/commands/tablecmds.c +++ b/src/backend/commands/tablecmds.c @@ -7630,6 +7630,9 @@ set_attnotnull(List **wqueue, Relation rel, AttrNumber attnum, bool recurse, Form_pg_attribute attForm; bool retval = false; + /* Guard against stack overflow due to overly deep inheritance tree. */ + check_stack_depth(); + tuple = SearchSysCacheCopyAttNum(RelationGetRelid(rel), attnum); if (!HeapTupleIsValid(tuple)) elog(ERROR, "cache lookup failed for attribute %d of relation %u", @@ -7716,6 +7719,9 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName, bool is_no_inherit = false; List *ready = NIL; + /* Guard against stack overflow due to overly deep inheritance tree. */ + check_stack_depth(); + /* * In cases of multiple inheritance, we might visit the same child more * than once. In the topmost call, set up a list that we fill with all @@ -9359,6 +9365,9 @@ ATAddCheckNNConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel, ListCell *child; ObjectAddress address = InvalidObjectAddress; + /* Guard against stack overflow due to overly deep inheritance tree. */ + check_stack_depth(); + /* At top level, permission check was done in ATPrepCmd, else do it */ if (recursing) ATSimplePermissions(AT_AddConstraint, rel, ATT_TABLE | ATT_FOREIGN_TABLE); @@ -12428,6 +12437,9 @@ dropconstraint_internal(Relation rel, HeapTuple constraintTup, DropBehavior beha return InvalidObjectAddress; *readyRels = lappend_oid(*readyRels, RelationGetRelid(rel)); + /* Guard against stack overflow due to overly deep inheritance tree. */ + check_stack_depth(); + /* At top level, permission check was done in ATPrepCmd, else do it */ if (recursing) ATSimplePermissions(AT_DropConstraint, rel, ATT_TABLE | ATT_FOREIGN_TABLE);