nethack-gwaa-kiwi/nethack
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Lua error reporting buffer overflow

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nhl_error() was clobbering the stack.  I assume that the 'source'
field in the Lua debugging structure is normally a file name, but
nethack loads an entire Lua script into one long string because it
usually comes out of the DLB container, and 'source' contained the
full string.  That would overflow the local buffer in nhl_error()
if nethack encountered a Lua problem and tried to report it. (In
my case, the problem was in a level description file modification.)

[Not something under user control unless user can modify dat/*.lua
and put the result into $HACKDIR/nhdat.]
This commit is contained in:
PatR
2020-01-24 12:52:35 -08:00
parent 424750867a
commit b2fa6292db
2 changed files with 12 additions and 3 deletions
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12
src/nhlua.c
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@@ -1,4 +1,4 @@
/* NetHack 3.7 nhlua.c $NHDT-Date: 1575246766 2019/12/02 00:32:46 $ $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.16 $ */
/* NetHack 3.7 nhlua.c $NHDT-Date: 1579899144 2020/01/24 20:52:24 $ $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.28 $ */
/* Copyright (c) 2018 by Pasi Kallinen */
/* NetHack may be freely redistributed. See license for details. */
@@ -44,8 +44,16 @@ const char *msg;
lua_getstack(L, 1, &ar);
lua_getinfo(L, "lS", &ar);
Sprintf(buf, "%s (line %i%s)", msg, ar.currentline, ar.source);
Sprintf(buf, "%s (line %d ", msg, ar.currentline);
Sprintf(eos(buf), "%.*s)",
/* (max length of ar.short_src is actually LUA_IDSIZE
so this is overkill for it, but crucial for ar.source) */
(int) (sizeof buf - (strlen(buf) + sizeof ")")),
ar.short_src); /* (used to be 'ar.source' here) */
lua_pushstring(L, buf);
#if 0 /* defined(PANICTRACE) && !defined(NO_SIGNALS) */
panictrace_setsignals(FALSE);
#endif
(void) lua_error(L);
/*NOTREACHED*/
}