fix(receive): guard maxsize against size_t overflow on cast

Casting a double larger than SIZE_MAX to size_t is undefined
behavior; bound-check maxsize before the cast.

1 files changed, 4 insertions, 2 deletions

diff --git a/test/testclnt.lua b/test/testclnt.lua
index 3e897c9..ec154ea 100644
--- a/test/testclnt.lua
+++ b/test/testclnt.lua
@@ -640,14 +640,16 @@ function test_maxsize()
     assert(not ok, "A5 failed: #prefix > maxsize should raise")
     ok = pcall(data.receive, data, 100, nil, 50)
     assert(not ok, "A6 failed: wanted > maxsize should raise")
+    ok = pcall(data.receive, data, "*l", nil, math.huge)
+    assert(not ok, "A7 failed: maxsize=math.huge should raise (size_t overflow)")
     data:settimeout(0.1)
     ok = pcall(data.receive, data, 50, nil, 100)
-    assert(ok, "A7 failed: wanted <= maxsize should not raise")
+    assert(ok, "A8 failed: wanted <= maxsize should not raise")
     data:settimeout(-1)
     remote [[ data:send('intact\n') ]]
     local line, err = data:receive("*l", nil, 100)
     assert(line == "intact",
-        "A8 failed: socket touched by a failed argcheck (err=" ..
+        "A9 failed: socket touched by a failed argcheck (err=" ..
         tostring(err) .. ")")
     pass("ok")