Attachment 95001 Details for Bug 38456 – Limit numeric parsing of character names

[patch] Limit numeric parsing of character names

Limit-numeric-parsing-of-character-names.patch (text/plain), 7.66 KB, created by Jason Crain on 2014-03-03 05:56:53 UTC

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Creator: Jason Crain

Created: 2014-03-03 05:56:53 UTC

Size: 7.66 KB

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obsolete

>From 79c536130d211a6f25212c3526bc8e377a0722c4 Mon Sep 17 00:00:00 2001
>From: Jason Crain <jason@aquaticape.us>
>Date: Fri, 28 Feb 2014 23:52:30 -0600
>Subject: [PATCH] Limit numeric parsing of character names
>
>When setting up the CharCodeToUnicode map, parse character names like
>xx or Axx for hex or decimal codes only if the font's Differences
>array meets the following criteria:
>  * All sequences must start between character codes 0 and 5.
>  * All names must successfully parse numerically.
>
>If all other methods fail, use the character code as a fallback.
>---
> poppler/GfxFont.cc      | 143 +++++++++++++++++++++++++++++++++++-------------
> poppler/GlobalParams.cc |   2 +-
> 2 files changed, 106 insertions(+), 39 deletions(-)
>
>diff --git a/poppler/GfxFont.cc b/poppler/GfxFont.cc
>index c54181b..3160d8a 100644
>--- a/poppler/GfxFont.cc
>+++ b/poppler/GfxFont.cc
>@@ -916,6 +916,94 @@ char *GfxFont::readEmbFontFile(XRef *xref, int *len) {
> // Gfx8BitFont
> //------------------------------------------------------------------------
> 
>+// Parse character names of the form 'Axx', 'xx', 'Ann', 'ABnn', or
>+// 'nn', where 'A' and 'B' are any letters, 'xx' is two hex digits,
>+// and 'nn' is decimal digits.
>+static GBool parseNumericName(char *s, GBool hex, unsigned int *u) {
>+  char *endptr;
>+
>+  // Strip leading alpha characters.
>+  if (hex) {
>+    int n = 0;
>+
>+    // Get string length while ignoring junk at end.
>+    while (isalnum(s[n]))
>+      ++n;
>+
>+    // Only 2 hex characters with optional leading alpha is allowed.
>+    if (n == 3 && isalpha(*s)) {
>+      ++s;
>+    } else if (n != 2) {
>+      return gFalse;
>+    }
>+  } else {
>+    // Strip up to two alpha characters.
>+    for (int i = 0; i < 2 && isalpha(*s); ++i)
>+      ++s;
>+  }
>+
>+  int v = strtol(s, &endptr, hex ? 16 : 10);
>+
>+  if (endptr == s)
>+    return gFalse;
>+
>+  // Skip trailing junk characters.
>+  while (*endptr != '\0' && !isalnum(*endptr))
>+    ++endptr;
>+
>+  if (*endptr == '\0') {
>+    if (u)
>+      *u = v;
>+    return gTrue;
>+  }
>+  return gFalse;
>+}
>+
>+// Returns gTrue if the font has character names like xx or Axx which
>+// should be parsed for hex or decimal values.
>+static GBool testForNumericNames(Dict *fontDict, GBool hex) {
>+  Object enc, diff, obj;
>+  GBool numeric = gTrue;
>+
>+  fontDict->lookup("Encoding", &enc);
>+  if (!enc.isDict()) {
>+    enc.free();
>+    return gFalse;
>+  }
>+
>+  enc.dictLookup("Differences", &diff);
>+  enc.free();
>+  if (!diff.isArray()) {
>+    diff.free();
>+    return gFalse;
>+  }
>+
>+  for (int i = 0; i < diff.arrayGetLength(); ++i) {
>+    diff.arrayGet(i, &obj);
>+    if (obj.isInt()) {
>+      // All sequences must start between character codes 0 and 5.
>+      if (obj.getInt() > 5) {
>+	numeric = gFalse;
>+	break;
>+      }
>+    } else if (obj.isName()) {
>+      // All character names must sucessfully parse.
>+      if (!parseNumericName(obj.getName(), hex, NULL)) {
>+	numeric = gFalse;
>+	break;
>+      }
>+    } else {
>+      numeric = gFalse;
>+      break;
>+    }
>+    obj.free();
>+  }
>+
>+  diff.free();
>+  obj.free();
>+  return numeric;
>+}
>+
> Gfx8BitFont::Gfx8BitFont(XRef *xref, const char *tagA, Ref idA, GooString *nameA,
> 			 GfxFontType typeA, Ref embFontIDA, Dict *fontDict):
>   GfxFont(tagA, idA, nameA, typeA, embFontIDA) {
>@@ -930,6 +1018,7 @@ Gfx8BitFont::Gfx8BitFont(XRef *xref, const char *tagA, Ref idA, GooString *nameA
>   int code;
>   char *charName;
>   GBool missing, hex;
>+  GBool numeric;
>   Unicode toUnicode[256];
>   CharCodeToUnicode *utu, *ctu2;
>   Unicode uBuf[8];
>@@ -1244,9 +1333,9 @@ Gfx8BitFont::Gfx8BitFont(XRef *xref, const char *tagA, Ref idA, GooString *nameA
> 	      (charName[2] >= 'A' && charName[2] <= 'F'))) ||
> 	    (strlen(charName) == 2 &&
> 	     isxdigit(charName[0]) && isxdigit(charName[1]) &&
>-	     ((charName[0] >= 'a' && charName[0] <= 'f') ||
>-	      (charName[0] >= 'A' && charName[0] <= 'F') ||
>-	      (charName[1] >= 'a' && charName[1] <= 'f') ||
>+	     // Only check idx 1 to avoid misidentifying a decimal
>+	     // number like a0
>+	     ((charName[1] >= 'a' && charName[1] <= 'f') ||
> 	      (charName[1] >= 'A' && charName[1] <= 'F')))) {
> 	  hex = gTrue;
> 	}
>@@ -1257,6 +1346,8 @@ Gfx8BitFont::Gfx8BitFont(XRef *xref, const char *tagA, Ref idA, GooString *nameA
>     }
>   }
> 
>+  numeric = testForNumericNames(fontDict, hex);
>+
>   // construct the char code -> Unicode mapping object
>   ctu = CharCodeToUnicode::make8BitToUnicode(toUnicode);
> 
>@@ -1280,22 +1371,18 @@ Gfx8BitFont::Gfx8BitFont(XRef *xref, const char *tagA, Ref idA, GooString *nameA
> 	    && (n = parseCharName(charName, uBuf, sizeof(uBuf)/sizeof(*uBuf), 
> 				  gFalse, // don't check simple names (pass 1)
> 				  gTrue, // do check ligatures
>-				  globalParams->getMapNumericCharNames(),
>+				  numeric,
> 				  hex,
> 				  gTrue))) { // do check variants
> 	  ctu->setMapping((CharCode)code, uBuf, n);
>-	} else if (globalParams->getMapUnknownCharNames()) {
>-	  // if the 'mapUnknownCharNames' flag is set, do a simple pass-through
>-	  // mapping for unknown character names
>-	  if (charName && charName[0]) {
>-	    for (n = 0; n < (int)(sizeof(uBuf)/sizeof(*uBuf)); ++n)
>-	      if (!(uBuf[n] = charName[n]))
>-		break;
>-	    ctu->setMapping((CharCode)code, uBuf, n);
>-	  } else {
>+	  continue;
>+	}
>+
>+	// if the 'mapUnknownCharNames' flag is set, do a simple pass-through
>+	// mapping for unknown character names
>+	if (globalParams->getMapUnknownCharNames()) {
> 	    uBuf[0] = code;
> 	    ctu->setMapping((CharCode)code, uBuf, 1);
>-	  }
> 	}
>       }
>     }
>@@ -1495,7 +1582,7 @@ static int parseCharName(char *charName, Unicode *uBuf, int uLen,
>   if (names && (uBuf[0] = globalParams->mapNameToUnicodeText(charName))) {
>     return 1;
>   }
>-  if (numeric) {
>+  if (globalParams->getMapNumericCharNames()) {
>     unsigned int n = strlen(charName);
>     // 3.3. otherwise, if the component is of the form "uni" (U+0075 U+006E
>     // U+0069) followed by a sequence of uppercase hexadecimal digits (0 .. 9,
>@@ -1538,30 +1625,10 @@ static int parseCharName(char *charName, Unicode *uBuf, int uLen,
> 	return 1;
>       }
>     }
>-    // Not in Adobe Glyph Mapping convention: look for names of the form 'Axx',
>-    // 'xx', 'Ann', 'ABnn', or 'nn', where 'A' and 'B' are any letters, 'xx' is
>-    // two hex digits, and 'nn' is 2-4 decimal digits
>-    if (hex && n == 3 && isalpha(charName[0]) &&
>-	isxdigit(charName[1]) && isxdigit(charName[2])) {
>-      sscanf(charName+1, "%x", (unsigned int *)uBuf);
>-      return 1;
>-    } else if (hex && n == 2 &&
>-	       isxdigit(charName[0]) && isxdigit(charName[1])) {
>-      sscanf(charName, "%x", (unsigned int *)uBuf);
>+    // Not in Adobe Glyph Mapping convention: look for names like xx
>+    // or Axx and parse for hex or decimal values.
>+    if (numeric && parseNumericName(charName, hex, uBuf))
>       return 1;
>-    } else if (!hex && n >= 2 && n <= 4 &&
>-	       isdigit(charName[0]) && isdigit(charName[1])) {
>-      uBuf[0] = (Unicode)atoi(charName);
>-      return 1;
>-    } else if (n >= 3 && n <= 5 &&
>-	       isdigit(charName[1]) && isdigit(charName[2])) {
>-      uBuf[0] = (Unicode)atoi(charName+1);
>-      return 1;
>-    } else if (n >= 4 && n <= 6 &&
>-	       isdigit(charName[2]) && isdigit(charName[3])) {
>-      uBuf[0] = (Unicode)atoi(charName+2);
>-      return 1;
>-    }
>   }
>   // 3.5. otherwise, map the component to the empty string
>   return 0;
>diff --git a/poppler/GlobalParams.cc b/poppler/GlobalParams.cc
>index 01a3157..e92889c 100644
>--- a/poppler/GlobalParams.cc
>+++ b/poppler/GlobalParams.cc
>@@ -633,7 +633,7 @@ GlobalParams::GlobalParams(const char *customPopplerDataDir)
>   minLineWidth = 0.0;
>   overprintPreview = gFalse;
>   mapNumericCharNames = gTrue;
>-  mapUnknownCharNames = gFalse;
>+  mapUnknownCharNames = gTrue;
>   printCommands = gFalse;
>   profileCommands = gFalse;
>   errQuiet = gFalse;
>-- 
>1.9.0
>

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Attachments on bug 38456: 48144 | 91907 | 94930 | 95001 | 95208

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