Commit c94a5532 for tesseract
commit c94a5532ee04db5a4919542832fd94caee5ea58f
Author: Stefan Weil <sw@weilnetz.de>
Date: Fri Aug 21 16:56:51 2026 +0200
Reject recoder code values outside the sane range at load
RecodedCharID::DeSerialize (hardened by 82727cc to check length_
only) still read the individual code values as raw signed int32.
UnicharCompress::ComputeCodeRange computes code_range_ as 1 plus the
maximum code using a signed > comparison, so a code value of -1
never raises the maximum and yields code_range_ = 0. SetupDecoder
then resizes is_valid_start_ to 0 and writes is_valid_start_[code(0)]
on the size-0 vector<bool>, an out-of-bounds write at a wild wrapped
index (deterministic crash) on LSTMRecognizer load. A code value of
INT32_MAX instead wraps code_range_ negative and makes resize()
throw.
Key changes:
- unicharcompress.h: validate each deserialized code value to be
within [0, UINT16_MAX), the same arbitrary cap used elsewhere for
.traineddata counts; reject the recoder otherwise.
- unicharcompress.h/.cpp: add defense-in-depth bounds assertions to
IsValidFirstCode and SetupDecoder, matching the style of the
NetworkIO assertions from 2f4d2f4.
- unittest: add recoder_test, which feeds a crafted UnicharCompress
with a -1 code and an INT32_MAX code and expects DeSerialize to
fail (on unpatched code the -1 case dies on the SEGV in
SetupDecoder, the huge case on the uncaught length_error), plus a
positive control that valid codes load and answer
code_range()/IsValidFirstCode() correctly.
Reported-by: Zhixi "Jace" Sun <g.mygenie@gmail.com>
Assisted-by: OpenCode / qwen3.8-27b-thinking (Alibaba Cloud)
Signed-off-by: Stefan Weil <sw@weilnetz.de>
diff --git a/Makefile.am b/Makefile.am
index 0bae5fd6..c17cf7fd 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1203,6 +1203,7 @@ endif # !DISABLED_LEGACY_ENGINE
check_PROGRAMS += progress_test
check_PROGRAMS += qrsequence_test
check_PROGRAMS += recodebeam_test
+check_PROGRAMS += recoder_test
check_PROGRAMS += rect_test
check_PROGRAMS += resultiterator_test
check_PROGRAMS += scanutils_test
@@ -1442,6 +1443,10 @@ recodebeam_test_SOURCES = unittest/recodebeam_test.cc
recodebeam_test_CPPFLAGS = $(unittest_CPPFLAGS)
recodebeam_test_LDADD = $(TRAINING_LIBS) $(ICU_I18N_LIBS) $(ICU_UC_LIBS)
+recoder_test_SOURCES = unittest/recoder_test.cc
+recoder_test_CPPFLAGS = $(unittest_CPPFLAGS)
+recoder_test_LDADD = $(TESS_LIBS)
+
rect_test_SOURCES = unittest/rect_test.cc
rect_test_CPPFLAGS = $(unittest_CPPFLAGS)
rect_test_LDADD = $(TESS_LIBS)
diff --git a/src/ccutil/unicharcompress.cpp b/src/ccutil/unicharcompress.cpp
index f909f76e..b3dd440f 100644
--- a/src/ccutil/unicharcompress.cpp
+++ b/src/ccutil/unicharcompress.cpp
@@ -400,6 +400,7 @@ void UnicharCompress::SetupDecoder() {
for (unsigned c = 0; c < encoder_.size(); ++c) {
const RecodedCharID &code = encoder_[c];
decoder_[code] = c;
+ ASSERT_HOST(code(0) >= 0 && code(0) < code_range_);
is_valid_start_[code(0)] = true;
RecodedCharID prefix = code;
uint32_t len = code.length();
diff --git a/src/ccutil/unicharcompress.h b/src/ccutil/unicharcompress.h
index 9b696d03..6919b7d2 100644
--- a/src/ccutil/unicharcompress.h
+++ b/src/ccutil/unicharcompress.h
@@ -84,7 +84,17 @@ public:
if (length_ > kMaxCodeLen) {
return false;
}
- return fp->DeSerialize(&code_[0], length_);
+ if (!fp->DeSerialize(&code_[0], length_)) {
+ return false;
+ }
+ // Code values index arrays sized from the maximum code; reject values
+ // that are out of the sane range for a recoded alphabet.
+ for (uint32_t i = 0; i < length_; ++i) {
+ if (code_[i] < 0 || code_[i] >= static_cast<int32_t>(UINT16_MAX)) {
+ return false;
+ }
+ }
+ return true;
}
bool operator==(const RecodedCharID &other) const {
if (length_ != other.length_) {
@@ -190,6 +200,7 @@ public:
int DecodeUnichar(const RecodedCharID &code) const;
// Returns true if the given code is a valid start or single code.
bool IsValidFirstCode(int code) const {
+ ASSERT_HOST(code >= 0 && code < code_range_);
return is_valid_start_[code];
}
// Returns a list of valid non-final next codes for a given prefix code,
diff --git a/unittest/recoder_test.cc b/unittest/recoder_test.cc
new file mode 100644
index 00000000..48dfa7ea
--- /dev/null
+++ b/unittest/recoder_test.cc
@@ -0,0 +1,91 @@
+///////////////////////////////////////////////////////////////////////
+// File: recoder_test.cc
+// Description: Tests that a UnicharCompress (LSTM recoder) with code
+// values outside the sane range is rejected at load.
+// Negative code values leave code_range_ at zero, so
+// SetupDecoder writes is_valid_start_[code(0)] out of
+// bounds on a size-0 vector<bool>; huge code values wrap
+// code_range_ and make resize() throw.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+///////////////////////////////////////////////////////////////////////
+
+#include "include_gunit.h"
+
+#include "serialis.h" // for TFile
+#include "unicharcompress.h"
+
+#include <cstdint>
+#include <vector>
+
+namespace tesseract {
+namespace {
+
+// Appends raw little-endian values to a byte buffer.
+class ByteWriter {
+public:
+ void PutU8(uint32_t v) { data_.push_back(static_cast<char>(v & 0xFF)); }
+ void PutU32(uint32_t v) {
+ for (int i = 0; i < 4; ++i) {
+ data_.push_back(static_cast<char>((v >> (8 * i)) & 0xFF));
+ }
+ }
+ void PutS32(int32_t v) { PutU32(static_cast<uint32_t>(v)); }
+ const std::vector<char> &data() const { return data_; }
+
+private:
+ std::vector<char> data_;
+};
+
+// A serialized UnicharCompress with one length-1 RecodedCharID per
+// given code value (self-normalizing).
+std::vector<char> MakeRecoder(const std::vector<int32_t> &codes) {
+ ByteWriter w;
+ w.PutU32(codes.size());
+ for (int32_t code : codes) {
+ w.PutU8(1); // self_normalized_
+ w.PutU32(1); // length_
+ w.PutS32(code); // code_[0]
+ }
+ return w.data();
+}
+
+// A recoder code of -1 keeps code_range_ at 0, so on unpatched code
+// SetupDecoder performs an out-of-bounds write into the size-0
+// is_valid_start_ vector<bool>.
+TEST(RecoderTest, RejectsNegativeCode) {
+ std::vector<char> bytes = MakeRecoder({-1});
+ TFile fp;
+ ASSERT_TRUE(fp.Open(bytes.data(), bytes.size()));
+ UnicharCompress recoder;
+ EXPECT_FALSE(recoder.DeSerialize(&fp));
+}
+
+// A recoder code of INT32_MAX wraps code_range_ to a negative value,
+// so on unpatched code SetupDecoder's resize() throws.
+TEST(RecoderTest, RejectsHugeCode) {
+ std::vector<char> bytes = MakeRecoder({INT32_MAX});
+ TFile fp;
+ ASSERT_TRUE(fp.Open(bytes.data(), bytes.size()));
+ UnicharCompress recoder;
+ EXPECT_FALSE(recoder.DeSerialize(&fp));
+}
+
+// A valid recoder must still be accepted and usable.
+TEST(RecoderTest, AcceptsValidCodes) {
+ std::vector<char> bytes = MakeRecoder({0, 1});
+ TFile fp;
+ ASSERT_TRUE(fp.Open(bytes.data(), bytes.size()));
+ UnicharCompress recoder;
+ ASSERT_TRUE(recoder.DeSerialize(&fp));
+ EXPECT_EQ(recoder.code_range(), 2);
+ EXPECT_TRUE(recoder.IsValidFirstCode(0));
+ EXPECT_TRUE(recoder.IsValidFirstCode(1));
+}
+
+} // namespace
+} // namespace tesseract