SL-19711 - viewer can't parse environments. Fixed max parsing bug

(cherry picked from commit eb0516b9940f200b32349d611f38f1ccee48005d)

1 files changed, 13 insertions, 7 deletions

diff --git a/indra/llcommon/llsdserialize.cpp b/indra/llcommon/llsdserialize.cpp
index e7482b601d..56cc141f0d 100644
--- a/indra/llcommon/llsdserialize.cpp
+++ b/indra/llcommon/llsdserialize.cpp
@@ -125,14 +125,20 @@ bool LLSDSerialize::deserialize(LLSD& sd, std::istream& str, llssize max_bytes)
 	char hdr_buf[MAX_HDR_LEN + 1] = ""; /* Flawfinder: ignore */
 	bool fail_if_not_legacy = false;
 
-	/*
-	 * Get the first line before anything. Don't read more than max_bytes:
-	 * this get() overload reads no more than (count-1) bytes into the
-	 * specified buffer. In the usual case when max_bytes exceeds
-	 * sizeof(hdr_buf), get() will read no more than sizeof(hdr_buf)-2.
-	 */
-	str.get(hdr_buf, llmin(max_bytes+1, sizeof(hdr_buf)-1), '\n');
+    /*
+     * Get the first line before anything. Don't read more than max_bytes:
+     * this get() overload reads no more than (count-1) bytes into the
+     * specified buffer. In the usual case when max_bytes exceeds
+     * sizeof(hdr_buf), get() will read no more than sizeof(hdr_buf)-2.
+     */
+    llssize max_hdr_read = MAX_HDR_LEN;
+	if (max_bytes != LLSDSerialize::SIZE_UNLIMITED)
+	{
+        max_hdr_read = llmin(max_bytes + 1, max_hdr_read);
+	}
+    str.get(hdr_buf, max_hdr_read, '\n');
 	auto inbuf = str.gcount();
+
 	// https://en.cppreference.com/w/cpp/io/basic_istream/get
 	// When the get() above sees the specified delimiter '\n', it stops there
 	// without pulling it from the stream. If it turns out that the stream