Fenrir Fixes: Logic Errors

[stenslae]

This fixes various Fenrir findings concerning logic errors, safety issues, resource leaks, and API bugs.

• Fixed a double-free on key1 in dh-pg-ka.c by changing the second call to free key2 .
• Fixed connection shutdown order in server-psk-nonblocking.c.
• Replaced system-conflicting shutdown() calls with TLS_shutdown() in example-lwip-native-echoclient.c.
• Constrained read size to RECV_MSG_LEN - 1 and added null-termination to the reply buffer in server.c.
• Corrected dead comparisons where unsigned size types were checked for < 0.
• Fixed UEFI file utility functions in utility_wolf.c where the logic checked the function pointer address ( fileSize == 0 ) rather than the returned file size ( fSize == 0 ).
• Corrected overflow arithmetic in server-dtls-demux.c.
• Fixed xmss_example.c to validate privSz instead of pubSz after retrieving the private key length.
• Duplicate Writes: Removed a redundant duplicate wolfSSL_write() call in client-ech.c.
• Fixed non-blocking TLS client shutdown loop in client-tls-nonblocking.c to evaluate the correct error variable.
• Fixed DTLS CID collision check in server-dtls-demux.c to verify connection CIDs against active connections.
• Appended missing trailing colons ( : ) to cipher-suite fallback list strings in PSK server examples.

[wolfSSL-Fenrir-bot]

Fenrir Automated Review — PR #585

Scan targets checked: wolfssl-examples-bugs, wolfssl-examples-src

Findings: 1
1 finding(s) posted as inline comments (see file-level comments below)

This review was generated automatically by Fenrir. Findings are non-blocking.

[wolfSSL-Fenrir-bot]

Fenrir Automated Review — PR #585

Scan targets checked: wolfssl-examples-bugs, wolfssl-examples-src

No new issues found in the changed files. ✅