WKT1 export: avoid division by zero. Fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=12854. Credit to OSS Fuzz

3 files changed, 78 insertions, 11 deletions

diff --git a/src/iso19111/common.cpp b/src/iso19111/common.cpp
index 57654d84..bdd836e1 100644
--- a/src/iso19111/common.cpp
+++ b/src/iso19111/common.cpp
@@ -172,21 +172,22 @@ void UnitOfMeasure::_exportToWKT(
 {
     const bool isWKT2 = formatter->version() == WKTFormatter::Version::WKT2;
 
-    if (formatter->forceUNITKeyword() && type() != Type::PARAMETRIC) {
+    const auto l_type = type();
+    if (formatter->forceUNITKeyword() && l_type != Type::PARAMETRIC) {
         formatter->startNode(WKTConstants::UNIT, !codeSpace().empty());
     } else if (!unitType.empty()) {
         formatter->startNode(unitType, !codeSpace().empty());
     } else {
-        if (isWKT2 && type() == Type::LINEAR) {
+        if (isWKT2 && l_type == Type::LINEAR) {
             formatter->startNode(WKTConstants::LENGTHUNIT,
                                  !codeSpace().empty());
-        } else if (isWKT2 && type() == Type::ANGULAR) {
+        } else if (isWKT2 && l_type == Type::ANGULAR) {
             formatter->startNode(WKTConstants::ANGLEUNIT, !codeSpace().empty());
-        } else if (isWKT2 && type() == Type::SCALE) {
+        } else if (isWKT2 && l_type == Type::SCALE) {
             formatter->startNode(WKTConstants::SCALEUNIT, !codeSpace().empty());
-        } else if (isWKT2 && type() == Type::TIME) {
+        } else if (isWKT2 && l_type == Type::TIME) {
             formatter->startNode(WKTConstants::TIMEUNIT, !codeSpace().empty());
-        } else if (isWKT2 && type() == Type::PARAMETRIC) {
+        } else if (isWKT2 && l_type == Type::PARAMETRIC) {
             formatter->startNode(WKTConstants::PARAMETRICUNIT,
                                  !codeSpace().empty());
         } else {
@@ -211,7 +212,7 @@ void UnitOfMeasure::_exportToWKT(
             formatter->addQuotedString(l_name);
         }
         const auto &factor = conversionToSI();
-        if (!isWKT2 || factor != 0.0) {
+        if (!isWKT2 || l_type != Type::TIME || factor != 0.0) {
             // Some TIMEUNIT do not have a conversion factor
             formatter->add(factor);
         }
diff --git a/src/iso19111/coordinateoperation.cpp b/src/iso19111/coordinateoperation.cpp
index 6f9b6283..8a10bc5a 100644
--- a/src/iso19111/coordinateoperation.cpp
+++ b/src/iso19111/coordinateoperation.cpp
@@ -2147,11 +2147,19 @@ void ParameterValue::_exportToWKT(io::WKTFormatter *formatter) const {
             // registered linear / angular unit.
             const auto &unitType = unit.type();
             if (unitType == common::UnitOfMeasure::Type::LINEAR) {
-                formatter->add(
-                    l_value.convertToUnit(*(formatter->axisLinearUnit())));
+                const auto &targetUnit = *(formatter->axisLinearUnit());
+                if (targetUnit.conversionToSI() == 0.0) {
+                    throw io::FormattingException(
+                        "cannot convert value to target linear unit");
+                }
+                formatter->add(l_value.convertToUnit(targetUnit));
             } else if (unitType == common::UnitOfMeasure::Type::ANGULAR) {
-                formatter->add(
-                    l_value.convertToUnit(*(formatter->axisAngularUnit())));
+                const auto &targetUnit = *(formatter->axisAngularUnit());
+                if (targetUnit.conversionToSI() == 0.0) {
+                    throw io::FormattingException(
+                        "cannot convert value to target angular unit");
+                }
+                formatter->add(l_value.convertToUnit(targetUnit));
             } else {
                 formatter->add(l_value.getSIValue());
             }
diff --git a/test/unit/test_io.cpp b/test/unit/test_io.cpp
index 157614b4..69ef9073 100644
--- a/test/unit/test_io.cpp
+++ b/test/unit/test_io.cpp
@@ -8965,3 +8965,61 @@ TEST(wkt_export, precision) {
             WKTFormatter::create(WKTFormatter::Convention::WKT1_GDAL).get()),
         wkt);
 }
+
+// ---------------------------------------------------------------------------
+
+// Avoid division by zero
+
+TEST(wkt_export, invalid_linear_unit) {
+    auto wkt = "PROJCS[\"WGS 84 / UTM zone 31N\",\n"
+               "    GEOGCS[\"WGS 84\",\n"
+               "        DATUM[\"WGS_1984\",\n"
+               "            SPHEROID[\"WGS 84\",6378137,298.257223563]],\n"
+               "        PRIMEM[\"Greenwich\",0],\n"
+               "        UNIT[\"degree\",0.0174532925199433]],\n"
+               "    PROJECTION[\"Transverse_Mercator\"],\n"
+               "    PARAMETER[\"latitude_of_origin\",0],\n"
+               "    PARAMETER[\"central_meridian\",3],\n"
+               "    PARAMETER[\"scale_factor\",0.9996],\n"
+               "    PARAMETER[\"false_easting\",500000],\n"
+               "    PARAMETER[\"false_northing\",0],\n"
+               "    UNIT[\"foo\",0]]";
+
+    auto obj = WKTParser().createFromWKT(wkt);
+    auto crs = nn_dynamic_pointer_cast<ProjectedCRS>(obj);
+    ASSERT_TRUE(crs != nullptr);
+
+    EXPECT_THROW(
+        crs->exportToWKT(
+            WKTFormatter::create(WKTFormatter::Convention::WKT1_GDAL).get()),
+        FormattingException);
+}
+
+// ---------------------------------------------------------------------------
+
+// Avoid division by zero
+
+TEST(wkt_export, invalid_angular_unit) {
+    auto wkt = "PROJCS[\"WGS 84 / UTM zone 31N\",\n"
+               "    GEOGCS[\"WGS 84\",\n"
+               "        DATUM[\"WGS_1984\",\n"
+               "            SPHEROID[\"WGS 84\",6378137,298.257223563]],\n"
+               "        PRIMEM[\"Greenwich\",0],\n"
+               "        UNIT[\"foo\",0]],\n"
+               "    PROJECTION[\"Transverse_Mercator\"],\n"
+               "    PARAMETER[\"latitude_of_origin\",0],\n"
+               "    PARAMETER[\"central_meridian\",3],\n"
+               "    PARAMETER[\"scale_factor\",0.9996],\n"
+               "    PARAMETER[\"false_easting\",500000],\n"
+               "    PARAMETER[\"false_northing\",0],\n"
+               "    UNIT[\"meter\",1]]";
+
+    auto obj = WKTParser().createFromWKT(wkt);
+    auto crs = nn_dynamic_pointer_cast<ProjectedCRS>(obj);
+    ASSERT_TRUE(crs != nullptr);
+
+    EXPECT_THROW(
+        crs->exportToWKT(
+            WKTFormatter::create(WKTFormatter::Convention::WKT1_GDAL).get()),
+        FormattingException);
+}