From 2ed74d73625da9cb668a77ec9a2febb9f522ea31 Mon Sep 17 00:00:00 2001
From: Even Rouault <even.rouault@spatialys.com>
Date: Tue, 29 Oct 2024 19:54:41 +0100
Subject: [PATCH] PDF: fix nullptr dereference on invalid file

Fixes https://issues.oss-fuzz.com/issues/376126833
---
 autotest/gdrivers/data/pdf/invalid_srs.pdf | Bin 0 -> 1787 bytes
 autotest/gdrivers/pdf.py                   |  11 +++++++++++
 frmts/pdf/pdfdataset.cpp                   |   5 +++--
 3 files changed, 14 insertions(+), 2 deletions(-)
 create mode 100644 autotest/gdrivers/data/pdf/invalid_srs.pdf

diff --git a/autotest/gdrivers/data/pdf/invalid_srs.pdf b/autotest/gdrivers/data/pdf/invalid_srs.pdf
new file mode 100644
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diff --git a/autotest/gdrivers/pdf.py b/autotest/gdrivers/pdf.py
index 109f8acaaf3e..7b74e9b5384c 100755
--- a/autotest/gdrivers/pdf.py
+++ b/autotest/gdrivers/pdf.py
@@ -3345,3 +3345,14 @@ def test_pdf_iso32000_esri_as_epsg():
     assert sr.GetAuthorityName(None) == "ESRI"
     assert sr.GetAuthorityCode(None) == "102422"
     assert gdal.GetLastErrorMsg() == ""
+
+
+###############################################################################
+# Test bugfix for https://issues.oss-fuzz.com/issues/376126833
+
+
+@pytest.mark.skipif(not have_read_support(), reason="no read support available")
+def test_pdf_iso32000_invalid_srs():
+
+    # Just test that this does not crash
+    gdal.Open("data/pdf/invalid_srs.pdf")
diff --git a/frmts/pdf/pdfdataset.cpp b/frmts/pdf/pdfdataset.cpp
index d481b1fdc158..cb57e2a96719 100644
--- a/frmts/pdf/pdfdataset.cpp
+++ b/frmts/pdf/pdfdataset.cpp
@@ -7074,8 +7074,9 @@ int PDFDataset::ParseMeasure(GDALPDFObject *poMeasure, double dfMediaBoxWidth,
                 // Check consistency of ESRI:xxxx and WKT definitions
                 if (poGCSWKT != nullptr)
                 {
-                    if (!EQUAL(oSRS_ESRI.GetName(), m_oSRS.GetName()) &&
-                        !oSRS_ESRI.IsSame(&m_oSRS))
+                    if (!m_oSRS.GetName() ||
+                        (!EQUAL(oSRS_ESRI.GetName(), m_oSRS.GetName()) &&
+                         !oSRS_ESRI.IsSame(&m_oSRS)))
                     {
                         CPLDebug("PDF",
                                  "Definition from ESRI:%d and WKT=%s do not "