commit 8d261262d974ab756d998d8315bd857354ecd826
author John Bowler <jbowler@acm.org> Sat Jun 18 13:37:11 2011 -0500
committer Glenn Randers-Pehrson <glennrp at users.sourceforge.net> Sat Jun 18 13:37:11 2011 -0500
tree 9ccccdd499c27bf1351d40f2a83f78cc46615b2e
parent c4a8214b77a5f2570cd2eb66cad7d5942b1c9a6a

[devel] Fixed pngvalid, simplified macros, added checking for 0 in sCAL.

pngrutil.c

diff --git a/pngrutil.c b/pngrutil.c
index 2142a5e..8510e99 100644
--- a/pngrutil.c
+++ b/pngrutil.c
@@ -2038,21 +2038,26 @@
    i = 1;
    state = 0;
 
-   if (png_ptr->chunkdata[1] == 45 /* negative width */ ||
-       !png_check_fp_number(png_ptr->chunkdata, slength, &state, &i) ||
+   if (!png_check_fp_number(png_ptr->chunkdata, slength, &state, &i) ||
        i >= slength || png_ptr->chunkdata[i++] != 0)
       png_warning(png_ptr, "Invalid sCAL chunk ignored: bad width format");
 
+   else if (!PNG_FP_IS_POSITIVE(state))
+      png_warning(png_ptr, "Invalid sCAL chunk ignored: non-positive width");
+
    else
    {
       png_size_t heighti = i;
 
       state = 0;
-      if (png_ptr->chunkdata[i] == 45 /* negative height */ ||
-          !png_check_fp_number(png_ptr->chunkdata, slength, &state, &i) ||
+      if (!png_check_fp_number(png_ptr->chunkdata, slength, &state, &i) ||
           i != slength)
          png_warning(png_ptr, "Invalid sCAL chunk ignored: bad height format");
 
+      else if (!PNG_FP_IS_POSITIVE(state))
+         png_warning(png_ptr,
+            "Invalid sCAL chunk ignored: non-positive height");
+
       else
          /* This is the (only) success case. */
          png_set_sCAL_s(png_ptr, info_ptr, png_ptr->chunkdata[0],