Merge pull request mozilla#8829 from Snuffleupagus/issue-8823

Attempt to improve the `EI` detection heuristics, for inline images, in streams containing `NUL` bytes (issue 8823)

src/core/parser.js

@@ -148,7 +148,8 @@ var Parser = (function ParserClosure() {
  * @returns {number} The inline stream length.
  */
  findDefaultInlineStreamEnd(stream) {
- const E = 0x45, I = 0x49, SPACE = 0x20, LF = 0xA, CR = 0xD, n = 5;
+ const E = 0x45, I = 0x49, SPACE = 0x20, LF = 0xA, CR = 0xD;
+ const n = 10, NUL = 0x0;
  let startPos = stream.pos, state = 0, ch, maybeEIPos;
  while ((ch = stream.getByte()) !== -1) {
  if (state === 0) {
@@ -159,10 +160,23 @@ var Parser = (function ParserClosure() {
  assert(state === 2);
  if (ch === SPACE || ch === LF || ch === CR) {
  maybeEIPos = stream.pos;
- // Let's check the next `n` bytes are ASCII... just be sure.
+ // Let's check that the next `n` bytes are ASCII... just to be sure.
  let followingBytes = stream.peekBytes(n);
- for (let i = 0; i < n; i++) {
+ for (let i = 0, ii = followingBytes.length; i < ii; i++) {
  ch = followingBytes[i];
+ if (ch === NUL && followingBytes[i + 1] !== NUL) {
+ // NUL bytes are not supposed to occur *outside* of inline
+ // images, but some PDF generators violate that assumption,
+ // thus breaking the EI detection heuristics used below.
+ //
+ // However, we can't unconditionally treat NUL bytes as "ASCII",
+ // since that *could* result in inline images being truncated.
+ //
+ // To attempt to address this, we'll still treat any *sequence*
+ // of NUL bytes as non-ASCII, but for a *single* NUL byte we'll
+ // continue checking the `followingBytes` (fixes issue8823.pdf).
+ continue;
+ }
  if (ch !== LF && ch !== CR && (ch < SPACE || ch > 0x7F)) {
  // Not a LF, CR, SPACE or any visible ASCII character, i.e.
  // it's binary stuff. Resetting the state.

test/pdfs/.gitignore

@@ -58,6 +58,7 @@
 !issue8697.pdf
 !issue8707.pdf
 !issue8798r.pdf
+!issue8823.pdf
 !bad-PageLabels.pdf
 !filled-background.pdf
 !ArabicCIDTrueType.pdf

test/test_manifest.json

@@ -2976,9 +2976,15 @@
  { "id": "issue8798",
  "file": "pdfs/issue8798r.pdf",
  "md5": "3a0e29f013d9edcceb5d852e37738a77",
+ "link": false,
+ "rounds": 1,
+ "type": "eq"
+ },
+ { "id": "issue8823",
+ "file": "pdfs/issue8823.pdf",
+ "md5": "ad02d4aa374b315bf1766038d002d57a",
+ "link": false,
  "rounds": 1,
- "lastPage": 1,
- "link": true,
  "type": "eq"
  },
  { "id": "issue8613",