Fix buffer-overrun bug in net

lib/pure/net.nim

@@ -690,11 +690,10 @@ when defineSsl:
     let ctx = SslContext(context: ssl.SSL_get_SSL_CTX)
     let hintString = if hint == nil: "" else: $hint
     let (identityString, pskString) = (ctx.clientGetPskFunc)(hintString)
-    if psk.len.cuint > max_psk_len:
+    if pskString.len.cuint > max_psk_len:
       return 0
     if identityString.len.cuint >= max_identity_len:
       return 0
-
     copyMem(identity, identityString.cstring, pskString.len + 1) # with the last zero byte
     copyMem(psk, pskString.cstring, pskString.len)
 
@@ -716,7 +715,7 @@ when defineSsl:
       max_psk_len: cint): cuint {.cdecl.} =
     let ctx = SslContext(context: ssl.SSL_get_SSL_CTX)
     let pskString = (ctx.serverGetPskFunc)($identity)
-    if psk.len.cint > max_psk_len:
+    if pskString.len.cint > max_psk_len:
       return 0
     copyMem(psk, pskString.cstring, pskString.len)
 

lib/system.nim

@@ -1444,7 +1444,7 @@ type # these work for most platforms:
     ## This is the same as the type `long double` in *C*.
     ## This C type is not supported by Nim's code generator.
 
-  cuchar* {.importc: "unsigned char", nodecl.} = char
+  cuchar* {.importc: "unsigned char", nodecl.} = uint8
     ## This is the same as the type `unsigned char` in *C*.
   cushort* {.importc: "unsigned short", nodecl.} = uint16
     ## This is the same as the type `unsigned short` in *C*.