From 2a93aba5cfcf6e241ab4f9392c13e3b74032c061 Mon Sep 17 00:00:00 2001
From: Andrew Murray <radarhere@users.noreply.github.com>
Date: Thu, 22 Feb 2024 18:56:26 +1100
Subject: [PATCH] Use strncpy to avoid buffer overflow

---
 Tests/icc/sGrey-v2-nano.icc | Bin 0 -> 290 bytes
 Tests/test_imagecms.py      |   5 +++++
 src/_imagingcms.c           |   9 ++++-----
 3 files changed, 9 insertions(+), 5 deletions(-)
 create mode 100644 Tests/icc/sGrey-v2-nano.icc

diff --git a/Tests/icc/sGrey-v2-nano.icc b/Tests/icc/sGrey-v2-nano.icc
new file mode 100644
index 0000000000000000000000000000000000000000..0e9edfd403182dd3ca815935cc85f33ec5dbd746
GIT binary patch
literal 290
zcmZQzU{uOU&MjsVU|`72D=Bgha*T|Kj8b5K#K6oT!obPE#~_=STwLHA>=wcR1jUKv
z#mOZ_IUqIye7nZL2;yDV%}C5k;hV$Xm^N{`e8QEs#kOw0V-V`FvRG15i<5yeTYxye
zyriH6NM8VAk?fElXCVCqh)t3Uih$yb5<oT=R6UT%z?$b?R0(3h0LbkS_U90=n;6AT
zCYKhKLFGk&X0S7DWzFU^;|mbkDAS;N!eF7Tq_;z~dd}^J?5U5}1{^!|$ngLFlGF;2
II~WWY0A|-bu>b%7

literal 0
HcmV?d00001

diff --git a/Tests/test_imagecms.py b/Tests/test_imagecms.py
index c80fab75b67..fbd78032e59 100644
--- a/Tests/test_imagecms.py
+++ b/Tests/test_imagecms.py
@@ -661,6 +661,11 @@ def test_auxiliary_channels_isolated() -> None:
                 assert_image_equal(test_image.convert(dst_format[2]), reference_image)
 
 
+def test_long_modes() -> None:
+    p = ImageCms.getOpenProfile("Tests/icc/sGrey-v2-nano.icc")
+    ImageCms.buildTransform(p, p, "ABCDEFGHI", "ABCDEFGHI")
+
+
 @pytest.mark.parametrize("mode", ("RGB", "RGBA", "RGBX"))
 def test_rgb_lab(mode: str) -> None:
     im = Image.new(mode, (1, 1))
diff --git a/src/_imagingcms.c b/src/_imagingcms.c
index 4d66dcc1085..84b8a7e71f9 100644
--- a/src/_imagingcms.c
+++ b/src/_imagingcms.c
@@ -201,8 +201,8 @@ cms_transform_new(cmsHTRANSFORM transform, char *mode_in, char *mode_out) {
 
     self->transform = transform;
 
-    strcpy(self->mode_in, mode_in);
-    strcpy(self->mode_out, mode_out);
+    strncpy(self->mode_in, mode_in, 8);
+    strncpy(self->mode_out, mode_out, 8);
 
     return (PyObject *)self;
 }
@@ -242,10 +242,9 @@ findLCMStype(char *PILmode) {
         // LabX equivalent like ALab, but not reversed -- no #define in lcms2
         return (COLORSPACE_SH(PT_LabV2) | CHANNELS_SH(3) | BYTES_SH(1) | EXTRA_SH(1));
     }
-
     else {
-        /* take a wild guess... but you probably should fail instead. */
-        return TYPE_GRAY_8; /* so there's no buffer overrun... */
+        /* take a wild guess... */
+        return TYPE_GRAY_8;
     }
 }