Merge pull request #20855 from benpicco/coap_block_finish-fix

nanocoap: always write at least 1 byte in coap_block2_finish()
RIOT-OS · Sep 12, 2024 · 1fa7db2 · 1fa7db2
2 parents 24ad7e7 + 66fe083
commit 1fa7db2
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/sys/net/application_layer/nanocoap/nanocoap.c b/sys/net/application_layer/nanocoap/nanocoap.c
@@ -1339,6 +1339,11 @@ bool coap_block_finish(coap_block_slicer_t *slicer, uint16_t option)
     uint32_t blkopt = _slicer2blkopt(slicer, more);
     size_t olen = _encode_uint(&blkopt);
 
+    /* ensure that we overwrite the dummy value set by coap_block2_init() */
+    if (!olen) {
+        olen = 1;
+    }
+
     coap_put_option(slicer->opt, option - delta, option, (uint8_t *)&blkopt, olen);
     return more;
 }