Fixes two stb_image issues that could occur with specially constructed HDR and PGM files.

Signed-off-by: Neil Bickford <[email protected]>

stb_image.h

@@ -108,7 +108,7 @@ RECENT REVISION HISTORY:
     Cass Everitt            Ryamond Barbiero                        github:grim210
     Paul Du Bois            Engin Manap        Aldo Culquicondor    github:sammyhw
     Philipp Wiesemann       Dale Weiler        Oriol Ferrer Mesia   github:phprus
-    Josh Tobin                                 Matthew Gregan       github:poppolopoppo
+    Josh Tobin              Neil Bickford      Matthew Gregan       github:poppolopoppo
     Julian Raschke          Gregory Mullen     Christian Floisand   github:darealshinji
     Baldur Karlsson         Kevin Schmidt      JR Smith             github:Michaelangel007
                             Brad Weinberger    Matvey Cherevko      github:mosra
@@ -7187,12 +7187,12 @@ static float *stbi__hdr_load(stbi__context *s, int *x, int *y, int *comp, int re
                   // Run
                   value = stbi__get8(s);
                   count -= 128;
-                  if (count > nleft) { STBI_FREE(hdr_data); STBI_FREE(scanline); return stbi__errpf("corrupt", "bad RLE data in HDR"); }
+                  if ((count == 0) || (count > nleft)) { STBI_FREE(hdr_data); STBI_FREE(scanline); return stbi__errpf("corrupt", "bad RLE data in HDR"); }
                   for (z = 0; z < count; ++z)
                      scanline[i++ * 4 + k] = value;
                } else {
                   // Dump
-                  if (count > nleft) { STBI_FREE(hdr_data); STBI_FREE(scanline); return stbi__errpf("corrupt", "bad RLE data in HDR"); }
+                  if ((count == 0) || (count > nleft)) { STBI_FREE(hdr_data); STBI_FREE(scanline); return stbi__errpf("corrupt", "bad RLE data in HDR"); }
                   for (z = 0; z < count; ++z)
                      scanline[i++ * 4 + k] = stbi__get8(s);
                }
@@ -7446,10 +7446,17 @@ static void *stbi__pnm_load(stbi__context *s, int *x, int *y, int *comp, int req
 
    out = (stbi_uc *) stbi__malloc_mad4(s->img_n, s->img_x, s->img_y, ri->bits_per_channel / 8, 0);
    if (!out) return stbi__errpuc("outofmem", "Out of memory");
-   stbi__getn(s, out, s->img_n * s->img_x * s->img_y * (ri->bits_per_channel / 8));
+   if (!stbi__getn(s, out, s->img_n * s->img_x * s->img_y * (ri->bits_per_channel / 8))) {
+      STBI_FREE(out);
+      return stbi__errpuc("bad PNM", "PNM file truncated");
+   }
 
    if (req_comp && req_comp != s->img_n) {
-      out = stbi__convert_format(out, s->img_n, req_comp, s->img_x, s->img_y);
+      if (ri->bits_per_channel == 16) {
+         out = (stbi_uc *) stbi__convert_format16((stbi__uint16 *) out, s->img_n, req_comp, s->img_x, s->img_y);
+      } else {
+         out = stbi__convert_format(out, s->img_n, req_comp, s->img_x, s->img_y);
+      }
       if (out == NULL) return out; // stbi__convert_format frees input on failure
    }
    return out;