crash on null input to ST_Union(raster, otherarg)

[jcasanov]

st_union() crash in any of the more-than-one argument variant.

select st_union(null::raster); — does not fail select st_union(null::raster, 1); — crash the server

attached is the backtrace of the query that crash, showed above

postgres version

---

PostgreSQL 12.3 (Debian 12.3-1.pgdg100+1) on x86_64-pc-linux-gnu,

compiled by gcc (Debian 8.3.0-6) 8.3.0, 64-bit

postgis full version

---

POSTGIS="2.5.4" [EXTENSION] PGSQL="120" GEOS="3.7.1-CAPI-1.11.1

27a5e771" PROJ="Rel. 5.2.0, September 15th, 2018" GDAL="GDAL 2.4.0, released 2018/12/14" LIBXML="2.9.4" LIBJSON="0.12.1" LIBPROTOBUF="1.3.1" RASTER

[jcasanov]

stack trace of the crash

[jcasanov]

This patch fixes the problem for me

diff --git a/raster/rt_pg/rtpg_mapalgebra.c b/raster/rt_pg/rtpg_mapalgebra.c
index b3b6323cb..33ec63a80 100644
--- a/raster/rt_pg/rtpg_mapalgebra.c
+++ b/raster/rt_pg/rtpg_mapalgebra.c
@@ -2896,8 +2896,11 @@ Datum RASTER_union_finalfn(PG_FUNCTION_ARGS)
 				PG_RETURN_NULL();
 			}
 		}
-		else
+		else {
 			_raster = iwr->bandarg[i].raster[0];
+			if (_raster == NULL)
+				continue;
+		}
 
 		/* first band, _rtn doesn't exist */
 		if (i < 1) {

[robe]

jcasanov,

Thanks for the patch. I'll try to check it out today.

[Regina Obe <lr@…>]

In b163027/git:

Fix for raster crash. References #4699 - Jaime Casanova (2nd Quadrant)

[Regina Obe <lr@…>]

In f70a085/git:

Fix bug fix notice references #4699

[Regina Obe <lr@…>]

In 43fd77f/git:

Fix for raster crash. References #4699 for 3.0.2 - Jaime Casanova (2nd Quadrant)

[Regina Obe <lr@…>]

In ce30368/git:

Fix for raster crash. References #4699 for 2.5.5 - Jaime Casanova (2nd Quadrant)

[Regina Obe <lr@…>]

In 2cec61e/git:

Fix for raster crash. References #4699 for 2.4.9 - Jaime Casanova (2nd Quadrant)