util.xml: Do not allow doctypes, comments or processing instructions
Yes. This is as bad as it sounds. CVE pending.
In Prosody itself, this only affects mod_websocket, which uses util.xml
to parse the <open/> frame, thus allowing unauthenticated remote DoS
using Billion Laughs. However, third-party modules using util.xml may
also be affected by this.
This commit installs handlers which disallow the use of doctype
declarations and processing instructions without any escape hatch. It,
by default, also introduces such a handler for comments, however, there
is a way to enable comments nontheless.
This is because util.xml is used to parse human-facing data, where
comments are generally a desirable feature, and also because comments
are generally harmless.
LUA_PATH=$(LUA_DEV)
IDN_PATH=..\..\libidn-1.15
OPENSSL_PATH=..\..\openssl-0.9.8k
LUA_INCLUDE=$(LUA_PATH)\include
LUA_LIB=$(LUA_PATH)\lib\lua5.1.lib
IDN_LIB=$(IDN_PATH)\win32\lib\libidn.lib
IDN_INCLUDE1=$(IDN_PATH)\lib
IDN_INCLUDE2=$(IDN_PATH)\win32\include
OPENSSL_LIB=$(OPENSSL_PATH)\out32dll\libeay32.lib
OPENSSL_INCLUDE=$(OPENSSL_PATH)\include
CL=cl /LD /MD /nologo
all: encodings.dll hashes.dll windows.dll
install: encodings.dll hashes.dll windows.dll
copy /Y *.dll ..\util\
clean:
del encodings.dll encodings.exp encodings.lib encodings.obj encodings.dll.manifest
del hashes.dll hashes.exp hashes.lib hashes.obj hashes.dll.manifest
del windows.dll windows.exp windows.lib windows.obj windows.dll.manifest
encodings.dll: encodings.c
$(CL) encodings.c /I"$(LUA_INCLUDE)" /I"$(IDN_INCLUDE1)" /I"$(IDN_INCLUDE2)" /link "$(LUA_LIB)" "$(IDN_LIB)" /export:luaopen_util_encodings
del encodings.exp encodings.lib encodings.obj encodings.dll.manifest
hashes.dll: hashes.c
$(CL) hashes.c /I"$(LUA_INCLUDE)" /I"$(OPENSSL_INCLUDE)" /link "$(LUA_LIB)" "$(OPENSSL_LIB)" /export:luaopen_util_hashes
del hashes.exp hashes.lib hashes.obj hashes.dll.manifest
windows.dll: windows.c
$(CL) windows.c /I"$(LUA_INCLUDE)" /link "$(LUA_LIB)" dnsapi.lib /export:luaopen_util_windows
del windows.exp windows.lib windows.obj windows.dll.manifest