GraphicsMagick: GenerateEXIFAttribute(): Assure that float and d...

changeset ca23f27fe474 in /hg/GraphicsMagick
details: http://hg.GraphicsMagick.org/hg/GraphicsMagick?cmd=changeset;node=ca23f27fe474
summary: GenerateEXIFAttribute(): Assure that float and double values are suitably alligned

diffstat:

 ChangeLog          |  5 +++++
 coders/tiff.c      |  2 +-
 magick/attribute.c |  8 ++++++--
 3 files changed, 12 insertions(+), 3 deletions(-)

diffs (61 lines):

diff -r c9b750fbb01f -r ca23f27fe474 ChangeLog
--- a/ChangeLog	Sat Apr 29 09:45:49 2023 -0500
+++ b/ChangeLog	Sat Apr 29 10:13:35 2023 -0500
@@ -1,5 +1,10 @@
 2023-04-29  Bob Friesenhahn  <[email protected]>
 
+	* magick/attribute.c (GenerateEXIFAttribute): Assure that float
+	and double values are suitably alligned.  Addresses SourceForge
+	issue #709 "Undefined behavior while loading a value of type float
+	from an unaligned address".
+
 	* coders/tiff.c (ReadTIFFImage): Validate that TIFFGetField() did
 	return count and text rather than just relying on its return
 	status.  Addresses SourceForge issue #710 "Undefined behavior
diff -r c9b750fbb01f -r ca23f27fe474 coders/tiff.c
--- a/coders/tiff.c	Sat Apr 29 09:45:49 2023 -0500
+++ b/coders/tiff.c	Sat Apr 29 10:13:35 2023 -0500
@@ -1,5 +1,5 @@
 /*
-% Copyright (C) 2003 - 2022 GraphicsMagick Group
+% Copyright (C) 2003 - 2023 GraphicsMagick Group
 % Copyright (C) 2002 ImageMagick Studio
 % Copyright 1991-1999 E. I. du Pont de Nemours and Company
 %
diff -r c9b750fbb01f -r ca23f27fe474 magick/attribute.c
--- a/magick/attribute.c	Sat Apr 29 09:45:49 2023 -0500
+++ b/magick/attribute.c	Sat Apr 29 10:13:35 2023 -0500
@@ -2156,6 +2156,7 @@
                   }
                 case EXIF_FMT_SINGLE:
                   {
+                    float fval;
                     if ((pval < tiffp) || ((pval+sizeof(float)) > tiffp_max))
                       {
                         if (logging)
@@ -2164,12 +2165,14 @@
                                                 (MAGICK_SSIZE_T) (pval-tiffp));
                         goto generate_attribute_failure;
                       }
-                    FormatString(s,"%f",(double) *(float *) pval);
+                    (void) memcpy(&fval,pval,sizeof(fval));
+                    FormatString(s,"%f",(double) fval);
                     value=AllocateString(s);
                     break;
                   }
                 case EXIF_FMT_DOUBLE:
                   {
+                    double dval;
                     if ((pval < tiffp) || ((pval+sizeof(double)) > tiffp_max))
                       {
                         if (logging)
@@ -2178,7 +2181,8 @@
                                                 (MAGICK_SSIZE_T) (pval-tiffp));
                         goto generate_attribute_failure;
                       }
-                    FormatString(s,"%f",*(double *) pval);
+                    (void) memcpy(&dval,pval,sizeof(dval));
+                    FormatString(s,"%f",dval);
                     value=AllocateString(s);
                     break;
                   }