Validate key length before calling encryption

Add error checking to make sure we aren't calling into aes decrypt
functions with larger key sizes, that would make decrypt read past the
end of it's data array.

libclamav/ole2_extract.c

@@ -2039,9 +2039,9 @@ static inline bool key_length_valid_aes_bits(const uint32_t keyLength)
 {
     switch (keyLength) {
         case SE_HEADER_EI_AES128_KEYSIZE:
-            /* fallthrough */
+            /* fall-through */
         case SE_HEADER_EI_AES192_KEYSIZE:
-            /* fallthrough */
+            /* fall-through */
         case SE_HEADER_EI_AES256_KEYSIZE:
             return true;
     }
@@ -2151,7 +2151,13 @@ static bool aes_128ecb_decrypt(const unsigned char *in, size_t length, unsigned
     size_t i;
     bool bRet = false;
 
+    if (SE_HEADER_EI_AES128_KEYSIZE != key->key_length_bits) {
+        cli_dbgmsg("ole2: Unsupported AES key length in aes_128ecb_decrypt\n");
+        goto done;
+    }
+
     nrounds = rijndaelSetupDecrypt(rk, (const unsigned char *)key->key, key->key_length_bits);
+
     if (!nrounds) {
         cli_errmsg("ole2: Unable to initialize decryption.\n");
         goto done;
@@ -2186,9 +2192,19 @@ static bool verify_key_aes(const encryption_key_t *const key, encryption_verifie
     uint8_t decrypted[AES_VERIFIER_HASH_LEN];
     uint32_t tmp = 0;
 
-    if (!aes_128ecb_decrypt(verifier->encrypted_verifier, sizeof(verifier->encrypted_verifier),
-                            decrypted, key)) {
-        goto done;
+    switch (key->key_length_bits) {
+        case SE_HEADER_EI_AES128_KEYSIZE:
+            if (!aes_128ecb_decrypt(verifier->encrypted_verifier, sizeof(verifier->encrypted_verifier),
+                                    decrypted, key)) {
+                goto done;
+            }
+            break;
+        case SE_HEADER_EI_AES192_KEYSIZE:
+            /* fall-through */
+        case SE_HEADER_EI_AES256_KEYSIZE:
+            /* fall-through */
+        default:
+            goto done;
     }
 
     (void)cl_sha1(decrypted, sizeof(verifier->encrypted_verifier), sha, NULL);
@@ -2297,14 +2313,26 @@ static bool initialize_encryption_key(const encryption_info_stream_standard_t *h
 
     switch (headerPtr->encryptionInfo.algorithmID) {
         case SE_HEADER_EI_AES128:
+            if (SE_HEADER_EI_AES128_KEYSIZE != headerPtr->encryptionInfo.keySize) {
+                cli_dbgmsg("ole2: Key length does not match algorithm id\n");
+                goto done;
+            }
             bAES = true;
             break;
         case SE_HEADER_EI_AES192:
             //not implemented
+            if (SE_HEADER_EI_AES192_KEYSIZE != headerPtr->encryptionInfo.keySize) {
+                cli_dbgmsg("ole2: Key length does not match algorithm id\n");
+                goto done;
+            }
             bAES = true;
             goto done;
         case SE_HEADER_EI_AES256:
             //not implemented
+            if (SE_HEADER_EI_AES256_KEYSIZE != headerPtr->encryptionInfo.keySize) {
+                cli_dbgmsg("ole2: Key length does not match algorithm id\n");
+                goto done;
+            }
             bAES = true;
             goto done;
         case SE_HEADER_EI_RC4:
@@ -2329,7 +2357,7 @@ static bool initialize_encryption_key(const encryption_info_stream_standard_t *h
 
     if (SE_HEADER_EI_AES_PROVIDERTYPE != headerPtr->encryptionInfo.providerType) {
         cli_dbgmsg("ole2: WARNING: Provider Type should be '0x%x', is '0x%x'\n",
-                    SE_HEADER_EI_AES_PROVIDERTYPE, headerPtr->encryptionInfo.providerType);
+                   SE_HEADER_EI_AES_PROVIDERTYPE, headerPtr->encryptionInfo.providerType);
         goto done;
     }