Fix stack-smashing bug in IDataSourceStream::readString() (#2468)

* Fix stack-smashing bug in IDataSourceStream::readString() * Add test case
SmingHub · Jan 17, 2022 · 95dc764 · 95dc764
1 parent 8a2eadd
commit 95dc764
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Showing 2 changed files with 8 additions and 1 deletion.
diff --git a/Sming/Core/Data/Stream/DataSourceStream.cpp b/Sming/Core/Data/Stream/DataSourceStream.cpp
@@ -45,7 +45,7 @@ String IDataSourceStream::readString(size_t maxLen)
 	size_t remain = maxLen;
 	while(remain != 0) {
 		char buffer[256];
-		size_t len = readBytes(buffer, remain);
+		size_t len = readBytes(buffer, std::min(sizeof(buffer), remain));
 		if(len == 0) {
 			break;
 		}

diff --git a/tests/HostTests/modules/Stream.cpp b/tests/HostTests/modules/Stream.cpp
@@ -83,6 +83,13 @@ class StreamTest : public TestGroup
 			REQUIRE(strlen(s.c_str()) == s.length());
 		}
 
+		TEST_CASE("readString (PR #2468)")
+		{
+			FSTR::Stream stream(FS_abstract);
+			String s = stream.readString(0x10000);
+			REQUIRE(s == FS_abstract);
+		}
+
 #ifndef DISABLE_NETWORK
 
 		TEST_CASE("ChunkedStream / StreamTransformer")