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| author | Stephen Frost <sfrost@snowman.net> | 2013-07-15 14:53:17 -0400 |
|---|---|---|
| committer | Stephen Frost <sfrost@snowman.net> | 2013-07-15 15:04:19 -0400 |
| commit | 4ed22e891f9915b02b753ee8763a8f2438234fc6 (patch) | |
| tree | c87b8fa747d27c5fed0f902d41e862b2aa7c37d1 | |
| parent | 4403a9d7913043d99de9e13a9b54c57ed0c4501c (diff) | |
Check get_tle_by_resno() result before deref
When creating a sort to support a group by, we need to look up the
target entry in the target list by the resno using get_tle_by_resno().
This particular code-path didn't check the result prior to attempting
to dereference it, while all other callers did. While I can't see a
way for this usage of get_tle_by_resno() to fail (you can't ask for
a column to be sorted on which isn't included in the group by), it's
probably best to check that we didn't end up with a NULL somehow
anyway than risk the segfault.
I'm willing to back-patch this if others feel it's necessary, but my
guess is new features are what might tickle this rather than anything
existing.
Missing check spotted by the Coverity scanner.
| -rw-r--r-- | src/backend/optimizer/plan/createplan.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c index 52bab79007e..2560e9cbc1e 100644 --- a/src/backend/optimizer/plan/createplan.c +++ b/src/backend/optimizer/plan/createplan.c @@ -4188,6 +4188,9 @@ make_sort_from_groupcols(PlannerInfo *root, SortGroupClause *grpcl = (SortGroupClause *) lfirst(l); TargetEntry *tle = get_tle_by_resno(sub_tlist, grpColIdx[numsortkeys]); + if (!tle) + elog(ERROR, "could not retrive tle for sort-from-groupcols"); + sortColIdx[numsortkeys] = tle->resno; sortOperators[numsortkeys] = grpcl->sortop; collations[numsortkeys] = exprCollation((Node *) tle->expr); |