crypto/tlscredspsk: Free username on finalize

When the creds->username property is set we allocate memory
for it in qcrypto_tls_creds_psk_prop_set_username(), but
we never free this when the QCryptoTLSCredsPSK is destroyed.
Free the memory in finalize.

This fixes a LeakSanitizer complaint in migration-test:

$ (cd build/asan; ASAN_OPTIONS="fast_unwind_on_malloc=0" QTEST_QEMU_BINARY=./qemu-system-x86_64 ./tests/qtest/migration-test --tap -k -p /x86_64/migration/precopy/unix/tls/psk)

=================================================================
==3867512==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 5 byte(s) in 1 object(s) allocated from:
    #0 0x5624e5c99dee in malloc (/mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/asan/qemu-system-x86_64+0x218edee) (BuildId: a9e623fa1009a9435c0142c037cd7b8c1ad04ce3)
    #1 0x7fb199ae9738 in g_malloc debian/build/deb/../../../glib/gmem.c:128:13
    #2 0x7fb199afe583 in g_strdup debian/build/deb/../../../glib/gstrfuncs.c:361:17
    #3 0x5624e82ea919 in qcrypto_tls_creds_psk_prop_set_username /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/asan/../../crypto/tlscredspsk.c:255:23
    #4 0x5624e812c6b5 in property_set_str /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/asan/../../qom/object.c:2277:5
    #5 0x5624e8125ce5 in object_property_set /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/asan/../../qom/object.c:1463:5
    #6 0x5624e8136e7c in object_set_properties_from_qdict /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/asan/../../qom/object_interfaces.c:55:14
    #7 0x5624e81372d2 in user_creatable_add_type /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/asan/../../qom/object_interfaces.c:112:5
    #8 0x5624e8137964 in user_creatable_add_qapi /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/asan/../../qom/object_interfaces.c:157:11
    #9 0x5624e891ba3c in qmp_object_add /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/asan/../../qom/qom-qmp-cmds.c:227:5
    #10 0x5624e8af9118 in qmp_marshal_object_add /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/asan/qapi/qapi-commands-qom.c:337:5
    #11 0x5624e8bd1d49 in do_qmp_dispatch_bh /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/asan/../../qapi/qmp-dispatch.c:128:5
    #12 0x5624e8cb2531 in aio_bh_call /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/asan/../../util/async.c:171:5
    #13 0x5624e8cb340c in aio_bh_poll /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/asan/../../util/async.c:218:13
    #14 0x5624e8c0be98 in aio_dispatch /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/asan/../../util/aio-posix.c:423:5
    #15 0x5624e8cba3ce in aio_ctx_dispatch /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/asan/../../util/async.c:360:5
    #16 0x7fb199ae0d3a in g_main_dispatch debian/build/deb/../../../glib/gmain.c:3419:28
    #17 0x7fb199ae0d3a in g_main_context_dispatch debian/build/deb/../../../glib/gmain.c:4137:7
    #18 0x5624e8cbe1d9 in glib_pollfds_poll /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/asan/../../util/main-loop.c:287:9
    #19 0x5624e8cbcb13 in os_host_main_loop_wait /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/asan/../../util/main-loop.c:310:5
    #20 0x5624e8cbc6dc in main_loop_wait /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/asan/../../util/main-loop.c:589:11
    #21 0x5624e6f3f917 in qemu_main_loop /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/asan/../../system/runstate.c:801:9
    #22 0x5624e893379c in qemu_default_main /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/asan/../../system/main.c:37:14
    #23 0x5624e89337e7 in main /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/asan/../../system/main.c:48:12
    #24 0x7fb197972d8f in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16
    #25 0x7fb197972e3f in __libc_start_main csu/../csu/libc-start.c:392:3
    #26 0x5624e5c16fa4 in _start (/mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/asan/qemu-system-x86_64+0x210bfa4) (BuildId: a9e623fa1009a9435c0142c037cd7b8c1ad04ce3)

SUMMARY: AddressSanitizer: 5 byte(s) leaked in 1 allocation(s).

Cc: [email protected]
Signed-off-by: Peter Maydell <[email protected]>
Reviewed-by: Daniel P. Berrangé <[email protected]>
Message-ID: <[email protected]>
Signed-off-by: Philippe Mathieu-Daudé <[email protected]>

crypto/tlscredspsk.c

@@ -243,6 +243,7 @@ qcrypto_tls_creds_psk_finalize(Object *obj)
     QCryptoTLSCredsPSK *creds = QCRYPTO_TLS_CREDS_PSK(obj);
 
     qcrypto_tls_creds_psk_unload(creds);
+    g_free(creds->username);
 }
 
 static void