Merge pull request #18230 from richardkchapman/HPCC-31139

HPCC-31139 Length field gets corrupted in resent encrypted packets Reviewed-by: Mark Kelly [email protected] Reviewed-by: Gavin Halliday <[email protected]> Merged-by: Gavin Halliday <[email protected]>
hpcc-systems · Jan 17, 2024 · a786733 · a786733
2 parents 71d4b75 + 695be14
commit a786733
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Showing 2 changed files with 4 additions and 3 deletions.
diff --git a/roxie/udplib/udptrs.cpp b/roxie/udplib/udptrs.cpp
@@ -571,8 +571,9 @@ class UdpReceiverEntry : public IUdpReceiverEntry
                         const char *data = buffer->data + sizeof(UdpPacketHeader);
                         const MemoryAttr &udpkey = getSecretUdpKey(true);
                         aesEncrypt(udpkey.get(), udpkey.length(), data, length, encryptBuffer);
-                        header->length = encryptBuffer.length();
-                        encryptBuffer.writeDirect(0, sizeof(UdpPacketHeader), header);   // Only really need length updating
+                        UdpPacketHeader newHeader;
+                        newHeader.length = encryptBuffer.length();
+                        encryptBuffer.writeDirect(offsetof(UdpPacketHeader, length), sizeof(newHeader.length), &newHeader.length);  // Only need to update the length - rest is the same
                         assertex(encryptBuffer.length() <= DATA_PAYLOAD);
                         data_socket->write(encryptBuffer.toByteArray(), encryptBuffer.length());
                     }

diff --git a/testing/unittests/jlibtests.cpp b/testing/unittests/jlibtests.cpp
@@ -3779,7 +3779,7 @@ class JLibOpensslAESTest : public CppUnit::TestFixture
                                 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x30, 0x31
                               };
         constexpr const char * prefix = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
-        constexpr unsigned lenPrefix = strlen(prefix);
+        unsigned lenPrefix = strlen(prefix);
 
         MemoryBuffer ciphertext1, ciphertext2, decrypted1, decrypted2;