commit dcc816d65cc8b29d04c84124d54be8acb66eb9aa
author Tom Sepez <tsepez@chromium.org> Wed Jul 17 22:16:09 2024 +0000
committer Pdfium LUCI CQ <pdfium-scoped@luci-project-accounts.iam.gserviceaccount.com> Wed Jul 17 22:16:09 2024 +0000
tree bebb4c2a383bc9e752522d69a4e7bee355833620
parent ae30a4dd4b11cf17058e2389399d80a4c692d25c

Avoid UNSAFE_TODO when making strings from C-style binary arrays.

ByteString doesn't have a constructor from span due to ambiguity
constraints, so the conversion must go:
  c-style array -> span -> ByteStringView -> Bytestring.

It is a little verbose but avoids any confusion about whether there
is a trailing NUL (there isn't).

Change-Id: Ibaa721132039f7939af126c087a399f977af2586
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/121890
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: Tom Sepez <tsepez@google.com>

core/fpdfapi/parser/cpdf_security_handler.cpp

diff --git a/core/fpdfapi/parser/cpdf_security_handler.cpp b/core/fpdfapi/parser/cpdf_security_handler.cpp
index 414692c..b96ccd8 100644
--- a/core/fpdfapi/parser/cpdf_security_handler.cpp
+++ b/core/fpdfapi/parser/cpdf_security_handler.cpp
@@ -521,7 +521,7 @@
       len--;
     }
   });
-  return UNSAFE_TODO(ByteString(okeybuf, len));
+  return ByteString(ByteStringView(pdfium::make_span(okeybuf).first(len)));
 }
 
 bool CPDF_SecurityHandler::CheckOwnerPassword(const ByteString& password) {
@@ -585,8 +585,8 @@
         FXSYS_memcpy(tempbuf, kDefaultPasscode, sizeof(kDefaultPasscode)));
     CRYPT_ArcFourCryptBlock(tempbuf,
                             pdfium::make_span(m_EncryptKey).first(key_len));
-    pEncryptDict->SetNewFor<CPDF_String>("U",
-                                         UNSAFE_TODO(ByteString(tempbuf, 32)));
+    pEncryptDict->SetNewFor<CPDF_String>(
+        "U", ByteString(ByteStringView(pdfium::make_span(tempbuf))));
   } else {
     CRYPT_md5_context md5 = CRYPT_MD5Start();
     CRYPT_MD5Update(&md5, kDefaultPasscode);
@@ -608,8 +608,8 @@
                               pdfium::make_span(tempkey).first(key_len));
     }
     CRYPT_MD5Generate(partial_digest_span, remaining_digest_span);
-    pEncryptDict->SetNewFor<CPDF_String>("U",
-                                         UNSAFE_TODO(ByteString(digest, 32)));
+    pEncryptDict->SetNewFor<CPDF_String>(
+        "U", ByteString(ByteStringView(pdfium::make_span(digest))));
   }
 
   InitCryptoHandler();
@@ -636,8 +636,8 @@
     CRYPT_SHA256Finish(&sha2, pdfium::make_span(digest1).first<32u>());
   }
   UNSAFE_TODO(FXSYS_memcpy(digest1 + 32, digest, 16));
-  pEncryptDict->SetNewFor<CPDF_String>("U",
-                                       UNSAFE_TODO(ByteString(digest1, 48)));
+  pEncryptDict->SetNewFor<CPDF_String>(
+      "U", ByteString(ByteStringView(pdfium::make_span(digest1))));
   if (m_Revision >= 6) {
     Revision6_Hash(password, UNSAFE_TODO(digest + 8), nullptr, digest1);
   } else {
@@ -651,8 +651,8 @@
   uint8_t iv[16] = {};
   CRYPT_AESSetIV(&aes, iv);
   CRYPT_AESEncrypt(&aes, digest1, m_EncryptKey);
-  pEncryptDict->SetNewFor<CPDF_String>("UE",
-                                       UNSAFE_TODO(ByteString(digest1, 32)));
+  pEncryptDict->SetNewFor<CPDF_String>(
+      "UE", ByteString(ByteStringView(pdfium::make_span(digest1).first<32>())));
 }
 
 void CPDF_SecurityHandler::AES256_SetPerms(CPDF_Dictionary* pEncryptDict) {
@@ -685,8 +685,8 @@
 
   uint8_t dest[16];
   CRYPT_AESEncrypt(&aes, dest, buf);
-  pEncryptDict->SetNewFor<CPDF_String>("Perms",
-                                       UNSAFE_TODO(ByteString(dest, 16)));
+  pEncryptDict->SetNewFor<CPDF_String>(
+      "Perms", ByteString(ByteStringView(pdfium::make_span(dest))));
 }
 
 void CPDF_SecurityHandler::InitCryptoHandler() {

fxjs/xfa/cfxjse_formcalc_context_embeddertest.cpp

diff --git a/fxjs/xfa/cfxjse_formcalc_context_embeddertest.cpp b/fxjs/xfa/cfxjse_formcalc_context_embeddertest.cpp
index 9bc5b92..00881bf 100644
--- a/fxjs/xfa/cfxjse_formcalc_context_embeddertest.cpp
+++ b/fxjs/xfa/cfxjse_formcalc_context_embeddertest.cpp
@@ -762,8 +762,7 @@
   const uint8_t test_string[] = {
       0x4c, 0x6f, 0x77, 0x65, 0x72, 0x28, 0x22, 0xc3,
       0x85, 0xc3, 0x85, 0xc3, 0x85, 0x22, 0x29};  // Lower("ÅÅÅ")
-  Execute(
-      UNSAFE_TODO(ByteString(test_string, sizeof(test_string))).AsStringView());
+  Execute(ByteStringView(pdfium::make_span(test_string)));
 }
 
 TEST_F(CFXJSE_FormCalcContextEmbedderTest, Ltrim) {