commit 82b558c70d3624142156e0b33c1d45751b6c3eff
author Lei Zhang <thestig@chromium.org> Tue Sep 27 17:52:16 2022 +0000
committer Pdfium LUCI CQ <pdfium-scoped@luci-project-accounts.iam.gserviceaccount.com> Tue Sep 27 17:52:16 2022 +0000
tree c49246b81fdb583be7c3f3e375e5c5c8395dd1cf
parent e319a902cba4c8a19a785dac8c043750b39f7c5a

Use FixedZeroedDataVector in JS_appResponse() callers.

Use FixedZeroedDataVector instead of DataVector since the vectors are a
fixed length. Also make the FixedZeroedDataVectors of type uint16_t, to
avoid having to cast when converting to WideStrings. Instead, use
pdfium::as_writable_bytes() when passing a span to JS_appResponse().

Change-Id: Ia6d04dfee02ea52f7ff56c1559ac8c1b1cebeb51
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/98452
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>

fpdfsdk/fpdfxfa/cpdfxfa_context.cpp

diff --git a/fpdfsdk/fpdfxfa/cpdfxfa_context.cpp b/fpdfsdk/fpdfxfa/cpdfxfa_context.cpp
index 4927a8a..137da39 100644
--- a/fpdfsdk/fpdfxfa/cpdfxfa_context.cpp
+++ b/fpdfsdk/fpdfxfa/cpdfxfa_context.cpp
@@ -16,7 +16,7 @@
 #include "core/fpdfapi/parser/cpdf_document.h"
 #include "core/fpdfapi/parser/cpdf_seekablemultistream.h"
 #include "core/fxcrt/autonuller.h"
-#include "core/fxcrt/data_vector.h"
+#include "core/fxcrt/fixed_zeroed_data_vector.h"
 #include "core/fxcrt/stl_util.h"
 #include "core/fxcrt/xml/cfx_xmldocument.h"
 #include "core/fxcrt/xml/cfx_xmlparser.h"
@@ -343,18 +343,19 @@
   if (!m_pFormFillEnv)
     return WideString();
 
-  int nLength = 2048;
-  DataVector<uint8_t> pBuff(nLength);
-  nLength = m_pFormFillEnv->JS_appResponse(wsQuestion, wsTitle, wsDefaultAnswer,
-                                           WideString(), bMark, pBuff);
-  if (nLength <= 0)
+  int byte_length = 2048;
+  FixedZeroedDataVector<uint16_t> buffer(byte_length / sizeof(uint16_t));
+  pdfium::span<uint16_t> buffer_span = buffer.writable_span();
+  byte_length = m_pFormFillEnv->JS_appResponse(
+      wsQuestion, wsTitle, wsDefaultAnswer, WideString(), bMark,
+      pdfium::as_writable_bytes(buffer_span));
+  if (byte_length <= 0)
     return WideString();
 
-  nLength = std::min(2046, nLength);
-  pBuff[nLength] = 0;
-  pBuff[nLength + 1] = 0;
-  return WideString::FromUTF16LE(reinterpret_cast<uint16_t*>(pBuff.data()),
-                                 nLength / sizeof(uint16_t));
+  byte_length = std::min(2046, byte_length);
+  buffer_span[byte_length / sizeof(uint16_t)] = 0;
+  return WideString::FromUTF16LE(buffer_span.data(),
+                                 byte_length / sizeof(uint16_t));
 }
 
 RetainPtr<IFX_SeekableReadStream> CPDFXFA_Context::DownloadURL(

fxjs/cjs_app.cpp

diff --git a/fxjs/cjs_app.cpp b/fxjs/cjs_app.cpp
index e7787c7..b417106 100644
--- a/fxjs/cjs_app.cpp
+++ b/fxjs/cjs_app.cpp
@@ -10,7 +10,7 @@
 
 #include <utility>
 
-#include "core/fxcrt/data_vector.h"
+#include "core/fxcrt/fixed_zeroed_data_vector.h"
 #include "core/fxcrt/stl_util.h"
 #include "fpdfsdk/cpdfsdk_formfillenvironment.h"
 #include "fpdfsdk/cpdfsdk_interactiveform.h"
@@ -549,18 +549,20 @@
   if (IsExpandedParamKnown(newParams[4]))
     swLabel = pRuntime->ToWideString(newParams[4]);
 
-  const int MAX_INPUT_BYTES = 2048;
-  DataVector<uint8_t> pBuff(MAX_INPUT_BYTES + 2);
-  int nLengthBytes = pRuntime->GetFormFillEnv()->JS_appResponse(
+  constexpr int kMaxBytes = 2048;
+  constexpr int kMaxWideChars = kMaxBytes / 2;
+  // Add 1 char for a NUL terminator.
+  FixedZeroedDataVector<uint16_t> buffer(kMaxWideChars + 1);
+  int byte_length = pRuntime->GetFormFillEnv()->JS_appResponse(
       swQuestion, swTitle, swDefault, swLabel, bPassword,
-      pdfium::make_span(pBuff).first(MAX_INPUT_BYTES));
+      pdfium::as_writable_bytes(buffer.writable_span().first(kMaxWideChars)));
 
-  if (nLengthBytes < 0 || nLengthBytes > MAX_INPUT_BYTES)
+  if (byte_length < 0 || byte_length > kMaxBytes)
     return CJS_Result::Failure(JSMessage::kParamTooLongError);
 
   return CJS_Result::Success(pRuntime->NewString(
-      WideString::FromUTF16LE(reinterpret_cast<uint16_t*>(pBuff.data()),
-                              nLengthBytes / sizeof(uint16_t))
+      WideString::FromUTF16LE(buffer.span().data(),
+                              byte_length / sizeof(uint16_t))
           .AsStringView()));
 }