Index: src/network/network_content.cpp
===================================================================
--- src/network/network_content.cpp	(revision 19613)
+++ src/network/network_content.cpp	(working copy)
@@ -377,12 +377,35 @@
 	}
 
 	byte buff[8192];
-	while (!gzeof(fin)) {
+	while (1) {
 		int read = gzread(fin, buff, sizeof(buff));
+		if (read == 0) {
+			/* According to documentation, it means either "underlying error"
+			 * or end of input stream. Also, according to zlib 1.2.3.5 changelog,
+			 * "Change gzeof() to return 0 on error instead of -1", we can't trust
+			 * gzeof() in the case of error.
+			 *
+			 * Testing shows 1.2.3.3 sets errnum to Z_STREAM_END and 1.2.4 to 0
+			 * in the case of correct end of input stream.
+			 *
+			 * For both 1.2.3.3 and 1.2.4, gzread() returns -1 for broken
+			 * and truncated files.
+			 *
+			 * XXX: does it always mean we have finished reading?
+			 * This could be a problem when reading data from stream.
+			 */
+			int errnum;
+			gzerror(fin, &errnum);
+			if (errnum != 0 && errnum != Z_STREAM_END) ret = false;
+			break;
+		}
 		if (read < 0 || (size_t)read != fwrite(buff, 1, read, fout)) {
 			ret = false;
 			break;
 		}
+		/* DO NOT DO THIS! It will fail to detect broken file with zlib 1.2.3.3!
+		 * We need to wait for gzread() to return -1.
+		 * if (read < sizeof(buff)) break; */
 	}
 
 exit: