Allow tor_gzip_uncompress to extract as much as possible from truncated compressed data. Also, fix a bug where truncated compressed data could break tor_gzip_uncompress. [This last part is a backport candidate.]

svn:r5247

2 files changed, 25 insertions, 5 deletions

diff --git a/src/or/directory.c b/src/or/directory.c
index f7dd7a807..feb6766c8 100644
--- a/src/or/directory.c
+++ b/src/or/directory.c
@@ -878,11 +878,11 @@ connection_dir_client_reached_eof(connection_t *conn)
     }
     /* Try declared compression first if we can. */
     if (compression > 0)
-      tor_gzip_uncompress(&new_body, &new_len, body, body_len, compression);
+      tor_gzip_uncompress(&new_body, &new_len, body, body_len, compression, 1);
     /* Okay, if that didn't work, and we think that it was compressed
      * differently, try that. */
     if (!new_body && guessed > 0 && compression != guessed)
-      tor_gzip_uncompress(&new_body, &new_len, body, body_len, guessed);
+      tor_gzip_uncompress(&new_body, &new_len, body, body_len, guessed, 1);
     /* If we're pretty sure that we have a compressed directory, and
      * we didn't manage to uncompress it, then warn and bail. */
     if (!plausible && !new_body) {
diff --git a/src/or/test.c b/src/or/test.c
index 6af607a7e..918278b9c 100644
--- a/src/or/test.c
+++ b/src/or/test.c
@@ -919,7 +919,7 @@ test_gzip(void)
     test_assert(!memcmp(buf2, "\037\213", 2)); /* Gzip magic. */
     test_eq(detect_compression_method(buf2, len1), GZIP_METHOD);
 
-    test_assert(!tor_gzip_uncompress(&buf3, &len2, buf2, len1, GZIP_METHOD));
+    test_assert(!tor_gzip_uncompress(&buf3, &len2, buf2, len1, GZIP_METHOD, 1));
     test_assert(buf3);
     test_streq(buf1,buf3);
 
@@ -933,20 +933,40 @@ test_gzip(void)
   test_assert(!memcmp(buf2, "\x78\xDA", 2)); /* deflate magic. */
   test_eq(detect_compression_method(buf2, len1), ZLIB_METHOD);
 
-  test_assert(!tor_gzip_uncompress(&buf3, &len2, buf2, len1, ZLIB_METHOD));
+  test_assert(!tor_gzip_uncompress(&buf3, &len2, buf2, len1, ZLIB_METHOD, 1));
   test_assert(buf3);
   test_streq(buf1,buf3);
 
+  /* Check whether we can uncompress concatenated, compresed strings. */
   tor_free(buf3);
   buf2 = tor_realloc(buf2, len1*2);
   memcpy(buf2+len1, buf2, len1);
-  test_assert(!tor_gzip_uncompress(&buf3, &len2, buf2, len1*2, ZLIB_METHOD));
+  test_assert(!tor_gzip_uncompress(&buf3, &len2, buf2, len1*2, ZLIB_METHOD, 1));
   test_eq(len2, (strlen(buf1)+1)*2);
   test_memeq(buf3,
              "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAZAAAAAAAAAAAAAAAAAAAZ\0"
              "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAZAAAAAAAAAAAAAAAAAAAZ\0",
              (strlen(buf1)+1)*2);
 
+  tor_free(buf1);
+  tor_free(buf2);
+  tor_free(buf3);
+
+  /* Check whether we can uncompress partial strings. */
+  buf1 = tor_strdup("String with low redundancy that won't be compressed much.");
+  test_assert(!tor_gzip_compress(&buf2, &len1, buf1, strlen(buf1)+1,ZLIB_METHOD));
+  tor_assert(len1>16);
+  /* when we allow an uncomplete string, we should succeed.*/
+  tor_assert(!tor_gzip_uncompress(&buf3, &len2, buf2, len1-16, ZLIB_METHOD, 0));
+  buf3[len2]='\0';
+  tor_assert(len2 > 5);
+  tor_assert(!strcmpstart(buf1, buf3));
+
+  /* when we demand a complete string, this must fail. */
+  tor_free(buf3);
+  tor_assert(tor_gzip_uncompress(&buf3, &len2, buf2, len1-16, ZLIB_METHOD, 1));
+  tor_assert(!buf3);
+
   tor_free(buf2);
   tor_free(buf3);
   tor_free(buf1);