From c6605c1bdf07e8fc026bf857d37628cbb5746bb8 Mon Sep 17 00:00:00 2001 From: Alvaro Herrera Date: Tue, 16 Jan 2024 12:27:52 +0100 Subject: [PATCH] Don't test already-referenced pointer for nullness Commit b8ba7344e9eb added in PQgetResult a derefence to a pointer returned by pqPrepareAsyncResult(), before some other code that was already testing that pointer for nullness. But since commit 618c16707a6d (in Postgres 15), pqPrepareAsyncResult() doesn't ever return NULL (a statically-allocated result is returned if OOM). So in branches 15 and up, we can remove the redundant pointer check with no harm done. However, in branch 14, pqPrepareAsyncResult() can indeed return NULL if it runs out of memory. Fix things there by adding a null pointer check before dereferencing the pointer. This should hint Coverity that the preexisting check is not redundant but necessary. Backpatch to 14, like b8ba7344e9eb. Per Coverity. --- src/interfaces/libpq/fe-exec.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/src/interfaces/libpq/fe-exec.c b/src/interfaces/libpq/fe-exec.c index 52d41658c1..7fbce907db 100644 --- a/src/interfaces/libpq/fe-exec.c +++ b/src/interfaces/libpq/fe-exec.c @@ -842,6 +842,8 @@ pqSaveWriteError(PGconn *conn) * using whatever is in conn->errorMessage. In any case, clear the async * result storage, and update our notion of how much error text has been * returned to the application. + * + * Note that in no case (not even OOM) do we return NULL. */ PGresult * pqPrepareAsyncResult(PGconn *conn) @@ -2138,7 +2140,7 @@ PQgetResult(PGconn *conn) * (In other words: we don't return a NULL after a pipeline * sync.) */ - if (res && res->resultStatus == PGRES_PIPELINE_SYNC) + if (res->resultStatus == PGRES_PIPELINE_SYNC) pqPipelineProcessQueue(conn); } else