1 files changed, 51 insertions, 13 deletions

diff --git a/src/common/compress.c b/src/common/compress.c
index 6513029f9c..472268a439 100644
--- a/src/common/compress.c
+++ b/src/common/compress.c
@@ -102,8 +102,13 @@ tor_compress_impl(int compress,
 
   stream = tor_compress_new(compress, method, compression_level);
 
-  if (stream == NULL)
+  if (stream == NULL) {
+    log_warn(LD_GENERAL, "NULL stream while %scompressing",
+             compress?"":"de");
+    log_debug(LD_GENERAL, "method: %d level: %d at len: %lu",
+              method, compression_level, (unsigned long)in_len);
     return -1;
+  }
 
   size_t in_len_orig = in_len;
   size_t out_remaining, out_alloc;
@@ -128,13 +133,26 @@ tor_compress_impl(int compress,
           // inputs.
           tor_compress_free(stream);
           stream = tor_compress_new(compress, method, compression_level);
+          if (stream == NULL) {
+            log_warn(LD_GENERAL, "NULL stream while %scompressing",
+                     compress?"":"de");
+            goto err;
+          }
         }
         break;
       case TOR_COMPRESS_OK:
         if (compress || complete_only) {
+          log_fn(protocol_warn_level, LD_PROTOCOL,
+                 "Unexpected %s while %scompressing",
+                 complete_only?"end of input":"result",
+                 compress?"":"de");
+          log_debug(LD_GENERAL, "method: %d level: %d at len: %lu",
+                    method, compression_level, (unsigned long)in_len);
           goto err;
         } else {
-          goto done;
+          if (in_len == 0) {
+            goto done;
+          }
         }
         break;
       case TOR_COMPRESS_BUFFER_FULL: {
@@ -524,28 +542,48 @@ tor_compress_process(tor_compress_state_t *state,
                      int finish)
 {
   tor_assert(state != NULL);
+  const size_t in_len_orig = *in_len;
+  const size_t out_len_orig = *out_len;
+  tor_compress_output_t rv;
 
   switch (state->method) {
     case GZIP_METHOD:
     case ZLIB_METHOD:
-      return tor_zlib_compress_process(state->u.zlib_state,
-                                       out, out_len, in, in_len,
-                                       finish);
+      rv = tor_zlib_compress_process(state->u.zlib_state,
+                                     out, out_len, in, in_len,
+                                     finish);
+      break;
     case LZMA_METHOD:
-      return tor_lzma_compress_process(state->u.lzma_state,
-                                       out, out_len, in, in_len,
-                                       finish);
+      rv =tor_lzma_compress_process(state->u.lzma_state,
+                                    out, out_len, in, in_len,
+                                    finish);
+      break;
     case ZSTD_METHOD:
-      return tor_zstd_compress_process(state->u.zstd_state,
-                                       out, out_len, in, in_len,
-                                       finish);
+      rv = tor_zstd_compress_process(state->u.zstd_state,
+                                     out, out_len, in, in_len,
+                                     finish);
+      break;
     case NO_METHOD:
-      return tor_cnone_compress_process(out, out_len, in, in_len,
-                                        finish);
+      rv = tor_cnone_compress_process(out, out_len, in, in_len,
+                                      finish);
+      break;
+    default:
     case UNKNOWN_METHOD:
       goto err;
   }
+  if (BUG((rv == TOR_COMPRESS_OK) &&
+          *in_len == in_len_orig &&
+          *out_len == out_len_orig)) {
+    log_warn(LD_GENERAL,
+             "More info on the bug: method == %s, finish == %d, "
+             " *in_len == in_len_orig == %lu, "
+             "*out_len == out_len_orig == %lu",
+             compression_method_get_human_name(state->method), finish,
+             (unsigned long)in_len_orig, (unsigned long)out_len_orig);
+    return TOR_COMPRESS_ERROR;
+  }
 
+  return rv;
  err:
   return TOR_COMPRESS_ERROR;
 }