Simplify CPDF_SecurityHandler.

Remove unused method params, impossible code, and mark methods const.

Change-Id: Iee95c7b931461e2aadcf2422650a0cd48c8f7696
Reviewed-on: https://pdfium-review.googlesource.com/17790
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>

3 files changed, 32 insertions, 45 deletions

diff --git a/core/fpdfapi/edit/cpdf_creator.cpp b/core/fpdfapi/edit/cpdf_creator.cpp
index 9064854779..38abb85822 100644
--- a/core/fpdfapi/edit/cpdf_creator.cpp
+++ b/core/fpdfapi/edit/cpdf_creator.cpp
@@ -803,10 +803,9 @@ void CPDF_Creator::InitID() {
   if (m_pEncryptDict && !pOldIDArray && m_pParser && !idArrayPreExisting) {
     if (m_pEncryptDict->GetStringFor("Filter") == "Standard") {
       ByteString user_pass = m_pParser->GetPassword();
-      uint32_t flag = PDF_ENCRYPT_CONTENT;
       m_pSecurityHandler = pdfium::MakeUnique<CPDF_SecurityHandler>();
       m_pSecurityHandler->OnCreate(m_pEncryptDict.Get(), m_pIDArray.get(),
-                                   user_pass, flag);
+                                   user_pass);
       m_bSecurityChanged = true;
     }
   }
diff --git a/core/fpdfapi/parser/cpdf_security_handler.cpp b/core/fpdfapi/parser/cpdf_security_handler.cpp
index ca0891a729..7eb5c42f72 100644
--- a/core/fpdfapi/parser/cpdf_security_handler.cpp
+++ b/core/fpdfapi/parser/cpdf_security_handler.cpp
@@ -87,7 +87,6 @@ bool IsValidKeyLengthForCipher(int cipher, int keylen) {
 CPDF_SecurityHandler::CPDF_SecurityHandler()
     : m_Version(0),
       m_Revision(0),
-      m_pEncryptDict(nullptr),
       m_Permissions(0),
       m_Cipher(FXCIPHER_NONE),
       m_KeyLen(0),
@@ -119,7 +118,7 @@ bool CPDF_SecurityHandler::CheckSecurity(const ByteString& password) {
   return CheckPassword(password, false, m_EncryptKey, m_KeyLen);
 }
 
-uint32_t CPDF_SecurityHandler::GetPermissions() {
+uint32_t CPDF_SecurityHandler::GetPermissions() const {
   return m_bOwnerUnlocked ? 0xFFFFFFFF : m_Permissions;
 }
 
@@ -186,7 +185,6 @@ bool CPDF_SecurityHandler::LoadDict(const CPDF_Dictionary* pEncryptDict) {
 }
 
 bool CPDF_SecurityHandler::LoadDict(const CPDF_Dictionary* pEncryptDict,
-                                    uint32_t type,
                                     int& cipher,
                                     int& key_len) {
   m_pEncryptDict = pEncryptDict;
@@ -332,7 +330,6 @@ bool CPDF_SecurityHandler::AES256_CheckPassword(const ByteString& password,
     CRYPT_SHA256Update(&sha, pkey + 32, 8);
     if (bOwner)
       CRYPT_SHA256Update(&sha, ukey.raw_str(), 48);
-
     CRYPT_SHA256Finish(&sha, digest);
   }
   if (memcmp(digest, pkey, 32) != 0)
@@ -350,12 +347,9 @@ bool CPDF_SecurityHandler::AES256_CheckPassword(const ByteString& password,
     CRYPT_SHA256Update(&sha, pkey + 40, 8);
     if (bOwner)
       CRYPT_SHA256Update(&sha, ukey.raw_str(), 48);
-
     CRYPT_SHA256Finish(&sha, digest);
   }
-  ByteString ekey = m_pEncryptDict
-                        ? m_pEncryptDict->GetStringFor(bOwner ? "OE" : "UE")
-                        : ByteString();
+  ByteString ekey = m_pEncryptDict->GetStringFor(bOwner ? "OE" : "UE");
   if (ekey.GetLength() < 32)
     return false;
 
@@ -409,6 +403,7 @@ bool CPDF_SecurityHandler::CheckPassword(const ByteString& password,
   return CheckUserPassword(password, false, key, key_len) ||
          CheckUserPassword(password, true, key, key_len);
 }
+
 bool CPDF_SecurityHandler::CheckUserPassword(const ByteString& password,
                                              bool bIgnoreEncryptMeta,
                                              uint8_t* key,
@@ -420,6 +415,7 @@ bool CPDF_SecurityHandler::CheckUserPassword(const ByteString& password,
   if (ukey.GetLength() < 16) {
     return false;
   }
+
   uint8_t ukeybuf[32];
   if (m_Revision == 2) {
     memcpy(ukeybuf, defpasscode, 32);
@@ -452,7 +448,7 @@ bool CPDF_SecurityHandler::CheckUserPassword(const ByteString& password,
 
 ByteString CPDF_SecurityHandler::GetUserPassword(
     const ByteString& owner_password,
-    int32_t key_len) {
+    int32_t key_len) const {
   ByteString okey = m_pEncryptDict->GetStringFor("O");
   uint8_t passcode[32];
   for (uint32_t i = 0; i < 32; i++) {
@@ -498,13 +494,13 @@ ByteString CPDF_SecurityHandler::GetUserPassword(
   }
   return ByteString(okeybuf, len);
 }
+
 bool CPDF_SecurityHandler::CheckOwnerPassword(const ByteString& password,
                                               uint8_t* key,
                                               int32_t key_len) {
   ByteString user_pass = GetUserPassword(password, key_len);
-  if (CheckUserPassword(user_pass, false, key, key_len)) {
+  if (CheckUserPassword(user_pass, false, key, key_len))
     return true;
-  }
   return CheckUserPassword(user_pass, true, key, key_len);
 }
 
@@ -513,13 +509,15 @@ bool CPDF_SecurityHandler::IsMetadataEncrypted() const {
 }
 
 void CPDF_SecurityHandler::OnCreateInternal(CPDF_Dictionary* pEncryptDict,
-                                            CPDF_Array* pIdArray,
+                                            const CPDF_Array* pIdArray,
                                             const ByteString& user_password,
                                             const ByteString& owner_password,
-                                            bool bDefault,
-                                            uint32_t type) {
-  int cipher = 0, key_len = 0;
-  if (!LoadDict(pEncryptDict, type, cipher, key_len)) {
+                                            bool bDefault) {
+  ASSERT(pEncryptDict);
+
+  int cipher = 0;
+  int key_len = 0;
+  if (!LoadDict(pEncryptDict, cipher, key_len)) {
     return;
   }
   ByteString owner_password_copy = owner_password;
@@ -610,21 +608,17 @@ void CPDF_SecurityHandler::OnCreateInternal(CPDF_Dictionary* pEncryptDict,
 }
 
 void CPDF_SecurityHandler::OnCreate(CPDF_Dictionary* pEncryptDict,
-                                    CPDF_Array* pIdArray,
+                                    const CPDF_Array* pIdArray,
                                     const ByteString& user_password,
-                                    const ByteString& owner_password,
-                                    uint32_t type) {
-  OnCreateInternal(pEncryptDict, pIdArray, user_password, owner_password, true,
-                   type);
+                                    const ByteString& owner_password) {
+  OnCreateInternal(pEncryptDict, pIdArray, user_password, owner_password, true);
   InitCryptoHandler();
 }
 
 void CPDF_SecurityHandler::OnCreate(CPDF_Dictionary* pEncryptDict,
-                                    CPDF_Array* pIdArray,
-                                    const ByteString& user_password,
-                                    uint32_t type) {
-  OnCreateInternal(pEncryptDict, pIdArray, user_password, ByteString(), false,
-                   type);
+                                    const CPDF_Array* pIdArray,
+                                    const ByteString& user_password) {
+  OnCreateInternal(pEncryptDict, pIdArray, user_password, ByteString(), false);
   InitCryptoHandler();
 }
 
diff --git a/core/fpdfapi/parser/cpdf_security_handler.h b/core/fpdfapi/parser/cpdf_security_handler.h
index 0ae2cfe66c..eb9574386e 100644
--- a/core/fpdfapi/parser/cpdf_security_handler.h
+++ b/core/fpdfapi/parser/cpdf_security_handler.h
@@ -17,8 +17,6 @@
 #define FXCIPHER_AES 2
 #define FXCIPHER_AES2 3
 
-#define PDF_ENCRYPT_CONTENT 0
-
 class CPDF_Array;
 class CPDF_CryptoHandler;
 class CPDF_Dictionary;
@@ -32,21 +30,19 @@ class CPDF_SecurityHandler {
   bool OnInit(const CPDF_Dictionary* pEncryptDict,
               const CPDF_Array* pIdArray,
               const ByteString& password);
-  uint32_t GetPermissions();
-  bool IsMetadataEncrypted() const;
-
   void OnCreate(CPDF_Dictionary* pEncryptDict,
-                CPDF_Array* pIdArray,
+                const CPDF_Array* pIdArray,
                 const ByteString& user_password,
-                const ByteString& owner_password,
-                uint32_t type = PDF_ENCRYPT_CONTENT);
-
+                const ByteString& owner_password);
   void OnCreate(CPDF_Dictionary* pEncryptDict,
-                CPDF_Array* pIdArray,
-                const ByteString& user_password,
-                uint32_t type = PDF_ENCRYPT_CONTENT);
+                const CPDF_Array* pIdArray,
+                const ByteString& user_password);
+
+  uint32_t GetPermissions() const;
+  bool IsMetadataEncrypted() const;
 
-  ByteString GetUserPassword(const ByteString& owner_password, int32_t key_len);
+  ByteString GetUserPassword(const ByteString& owner_password,
+                             int32_t key_len) const;
   bool CheckPassword(const ByteString& user_password,
                      bool bOwner,
                      uint8_t* key,
@@ -59,7 +55,6 @@ class CPDF_SecurityHandler {
  private:
   bool LoadDict(const CPDF_Dictionary* pEncryptDict);
   bool LoadDict(const CPDF_Dictionary* pEncryptDict,
-                uint32_t type,
                 int& cipher,
                 int& key_len);
 
@@ -83,11 +78,10 @@ class CPDF_SecurityHandler {
                        bool bEncryptMetadata,
                        const uint8_t* key);
   void OnCreateInternal(CPDF_Dictionary* pEncryptDict,
-                        CPDF_Array* pIdArray,
+                        const CPDF_Array* pIdArray,
                         const ByteString& user_password,
                         const ByteString& owner_password,
-                        bool bDefault,
-                        uint32_t type);
+                        bool bDefault);
   bool CheckSecurity(const ByteString& password);
 
   void InitCryptoHandler();