From 7083ac56c780ea07809b48a22f6d7e9a9d70d25e Mon Sep 17 00:00:00 2001
From: Even Rouault <even.rouault@spatialys.com>
Date: Tue, 18 Feb 2025 18:56:38 +0100
Subject: [PATCH] CSV: emit error when unbalanced double quotes are detected

Fixes #11845
---
 .../ogr/data/csv/unbalanced_double_quotes.csv    |  3 +++
 autotest/ogr/ogr_csv.py                          | 16 ++++++++++++++++
 port/cpl_csv.cpp                                 |  8 ++++++++
 3 files changed, 27 insertions(+)
 create mode 100644 autotest/ogr/data/csv/unbalanced_double_quotes.csv

diff --git a/autotest/ogr/data/csv/unbalanced_double_quotes.csv b/autotest/ogr/data/csv/unbalanced_double_quotes.csv
new file mode 100644
index 000000000000..dc36a60ed855
--- /dev/null
+++ b/autotest/ogr/data/csv/unbalanced_double_quotes.csv
@@ -0,0 +1,3 @@
+id,txt
+1,"foo""
+2,bar
diff --git a/autotest/ogr/ogr_csv.py b/autotest/ogr/ogr_csv.py
index b7f2c87a588c..d1e6be1c8b3e 100755
--- a/autotest/ogr/ogr_csv.py
+++ b/autotest/ogr/ogr_csv.py
@@ -3482,6 +3482,22 @@ def test_ogr_schema_override_wkt(tmp_vsimem):
         assert f.GetGeometryRef().ExportToWkt() == "POINT (1 2)"
 
 
+###############################################################################
+# Test reading CSV with unbalanced double-quotes
+
+
+@gdaltest.enable_exceptions()
+def test_ogr_csv_unbalanced_double_quotes():
+
+    with ogr.Open("data/csv/unbalanced_double_quotes.csv") as ds:
+        lyr = ds.GetLayer(0)
+        with pytest.raises(
+            Exception,
+            match="CSV file has unbalanced number of double-quotes. Corrupted data will likely be returned",
+        ):
+            lyr.GetNextFeature()
+
+
 ###############################################################################
 
 
diff --git a/port/cpl_csv.cpp b/port/cpl_csv.cpp
index 36e0216f39ff..332074647fdb 100644
--- a/port/cpl_csv.cpp
+++ b/port/cpl_csv.cpp
@@ -706,6 +706,14 @@ CSVReadParseLineGeneric(void *fp, const char *(*pfnReadLine)(void *, size_t),
     {
         CPLError(CE_Failure, CPLE_OutOfMemory, "%s", e.what());
     }
+
+    if (bInString)
+    {
+        CPLError(CE_Failure, CPLE_AppDefined,
+                 "CSV file has unbalanced number of double-quotes. Corrupted "
+                 "data will likely be returned");
+    }
+
     return nullptr;
 }