6 files changed, 136 insertions, 2 deletions

diff --git a/generic/tkImgGIF.c b/generic/tkImgGIF.c
index 1c28b54..be90f06 100644
--- a/generic/tkImgGIF.c
+++ b/generic/tkImgGIF.c
@@ -1571,6 +1571,7 @@ Fread(
 	}
 	memcpy(dst, handle->data, (size_t) (hunk * count));
 	handle->data += hunk * count;
+	handle->length -= hunk * count;
 	return (int)(hunk * count);
     }
 
diff --git a/tests/corruptMangled.gif b/tests/corruptMangled.gif
new file mode 100644
index 0000000..ce043f0
--- /dev/null
+++ b/tests/corruptMangled.gif
@@ -0,0 +1,2 @@
+GIF89aÂ33ÿÿ33ÿ3ÿ3ÿ33ÿÿÿÿ3ÿÿÿ!ù
+,!xºÜ-0Bw¤ïÚ¥µê×Jâ8Uæªkir/3Re7  ;
\ No newline at end of file
diff --git a/tests/corruptMangled4G.gif b/tests/corruptMangled4G.gif
new file mode 100644
index 0000000..7dfde0e
--- /dev/null
+++ b/tests/corruptMangled4G.gif
@@ -0,0 +1,2 @@
+GIF89aÂf3ÿÿ33ÿ3ÿ3ÿ33ÿÿÿÿ3ÿÿÿ!ù
+,!xºÜ-0Bw¤ïÚ¥µê×Jâ8Uæªkir/3Re7  ;
\ No newline at end of file
diff --git a/tests/corruptTruncated.gif b/tests/corruptTruncated.gif
new file mode 100644
index 0000000..948305a
--- /dev/null
+++ b/tests/corruptTruncated.gif
diff --git a/tests/imgPhoto.test b/tests/imgPhoto.test
index 86da23d..4f3611e 100644
--- a/tests/imgPhoto.test
+++ b/tests/imgPhoto.test
@@ -59,7 +59,13 @@ set README [makeFile {
 set teapotPhotoFile [file join [file dirname [info script]] teapot.ppm]
 testConstraint hasTeapotPhoto [file exists $teapotPhotoFile]
 
-# ----------------------------------------------------------------------
+proc base64ok {} {
+    expr {
+        ![catch {package require base64}]
+    }
+}
+
+testConstraint base64PackageNeeded [base64ok]
 
 test imgPhoto-1.1 {options for photo images} -body {
     image create photo photo1 -width 79 -height 83
@@ -1242,7 +1248,130 @@ test imgPhoto-17.3 {photo write: format guessing from filename} -setup {
     catch {removeFile $f}
 } -result "P6\n"
 
-# ----------------------------------------------------------------------
+# Reject corrupted or truncated image [Bug b601ce3ab1].
+# WARNING - tests 18.1-18.9 will cause a segfault on 8.5.19 and lower,
+#           and on 8.6.6 and lower.
+test imgPhoto-18.1 {Reject corrupted GIF (binary string)} -constraints {
+    base64PackageNeeded
+} -setup {
+    package require base64
+    set data [base64::decode {
+	R0lGODlhwjMz//8zM/8z/zP/MzP/////M////yH5CiwheLrcLTBCd6Tv2qW16tdK4jhV
+	5qpraXIvM1JlNyAgOw==
+    }]
+} -body {
+    image create photo gif1 -data $data
+} -cleanup {
+    catch {image delete gif1}
+} -returnCodes error -result {error reading color map|not enough free memory for image buffer} -match regexp
+test imgPhoto-18.2 {Reject corrupted GIF (base 64 string)} -setup {
+    set data {
+	R0lGODlhwjMz//8zM/8z/zP/MzP/////M////yH5CiwheLrcLTBCd6Tv2qW16tdK4jhV
+	5qpraXIvM1JlNyAgOw==
+    }
+} -body {
+    image create photo gif1 -data $data
+} -cleanup {
+    catch {image delete gif1}
+} -returnCodes error -result {error reading color map|not enough free memory for image buffer} -match regexp
+test imgPhoto-18.3 {Reject corrupted GIF (file)} -setup {
+    set fileName [file join [file dirname [info script]] corruptMangled.gif]
+} -body {
+    image create photo gif1 -file $fileName
+} -cleanup {
+    catch {image delete gif1}
+} -returnCodes error -result {error reading color map|not enough free memory for image buffer} -match regexp
+test imgPhoto-18.4 {Reject truncated GIF (binary string)} -constraints {
+    base64PackageNeeded
+} -setup {
+    package require base64
+    set data [base64::decode {
+	R0lGODlhEAAQAMIHAAAAADMz//8zM/8z/zP/MzP///8=
+    }]
+} -body {
+    image create photo gif1 -data $data
+} -cleanup {
+    catch {image delete gif1}
+} -returnCodes error -result {error reading color map}
+test imgPhoto-18.5 {Reject truncated GIF (base 64 string)} -setup {
+    set data {
+	R0lGODlhEAAQAMIHAAAAADMz//8zM/8z/zP/MzP///8=
+    }
+} -body {
+    image create photo gif1 -data $data
+} -cleanup {
+    catch {image delete gif1}
+} -returnCodes error -result {error reading color map}
+test imgPhoto-18.6 {Reject truncated GIF (file)} -setup {
+    set fileName [file join [file dirname [info script]] corruptTruncated.gif]
+} -body {
+    image create photo gif1 -file $fileName
+} -cleanup {
+    catch {image delete gif1}
+} -returnCodes error -result {error reading color map}
+test imgPhoto-18.7 {Reject corrupted GIF (> 4Gb) (binary string)} -constraints {
+    base64PackageNeeded
+} -setup {
+    package require base64
+    set data [base64::decode {
+	R0lGODlhwmYz//8zM/8z/zP/MzP/////M////yH5Ciwhe
+	LrcLTBCd6Tv2qW16tdK4jhV5qpraXIvM1JlNyAgOw==
+    }]
+} -body {
+    image create photo gif1 -data $data
+} -cleanup {
+    catch {image delete gif1}
+} -returnCodes error -result {error reading color map|not enough free memory for image buffer} -match regexp
+test imgPhoto-18.8 {Reject corrupted GIF (> 4Gb) (base 64 string)} -setup {
+    set data {
+	R0lGODlhwmYz//8zM/8z/zP/MzP/////M////yH5Ciwhe
+	LrcLTBCd6Tv2qW16tdK4jhV5qpraXIvM1JlNyAgOw==
+    }
+} -body {
+    image create photo gif1 -data $data
+} -cleanup {
+    catch {image delete gif1}
+} -returnCodes error -result {error reading color map|not enough free memory for image buffer} -match regexp
+test imgPhoto-18.9 {Reject corrupted GIF (> 4Gb) (file)} -setup {
+    set fileName [file join [file dirname [info script]] corruptMangled4G.gif]
+} -body {
+    image create photo gif1 -file $fileName
+} -cleanup {
+    catch {image delete gif1}
+} -returnCodes error -result {error reading color map|not enough free memory for image buffer} -match regexp
+test imgPhoto-18.10 {Valid GIF (binary string)} -constraints {
+    base64PackageNeeded
+} -setup {
+    # Test the binary string reader with a valid GIF.
+    # This is not tested elsewhere.
+    # Tests 18.11, 18.12, with matching data, are included for completeness.
+    package require base64
+    set data [base64::decode {
+	R0lGODlhEAAQAMIHAAAAADMz//8zM/8z/zP/MzP/////M////yH5BAEKAAcALAAA
+	AAAQABAAAAMheLrcLTBCd6QV79qlterXB0riOFXmmapraXIvM1IdZTcJADs=
+    }]
+} -body {
+    image create photo gif1 -data $data
+} -cleanup {
+    catch {image delete gif1}
+} -result gif1
+test imgPhoto-18.11 {Valid GIF (base 64 string)} -setup {
+    set data {
+	R0lGODlhEAAQAMIHAAAAADMz//8zM/8z/zP/MzP/////M////yH5BAEKAAcALAAA
+	AAAQABAAAAMheLrcLTBCd6QV79qlterXB0riOFXmmapraXIvM1IdZTcJADs=
+    }
+} -body {
+    image create photo gif1 -data $data
+} -cleanup {
+    catch {image delete gif1}
+} -result gif1
+test imgPhoto-18.12 {Valid GIF (file)} -setup {
+    set fileName [file join [file dirname [info script]] red.gif]
+} -body {
+    image create photo gif1 -file $fileName
+} -cleanup {
+    catch {image delete gif1}
+} -result gif1
 
 catch {rename foreachPixel {}}
 catch {rename checkImgTrans {}}
diff --git a/tests/red.gif b/tests/red.gif
new file mode 100644
index 0000000..1d12ebb
--- /dev/null
+++ b/tests/red.gif