Explorar o código

Bug: Loading a corrupted binary file can segfault

The size of the list of upvalue names are stored separated from the
size of the list of upvalues, but they share the same array.
Roberto Ierusalimschy %!s(int64=2) %!d(string=hai) anos
pai
achega
ab859fe59b
Modificáronse 3 ficheiros con 22 adicións e 2 borrados
  1. 6 2
      ldump.c
  2. 2 0
      lundump.c
  3. 14 0
      testes/calls.lua

+ 6 - 2
ldump.c

@@ -10,6 +10,7 @@
 #include "lprefix.h"
 
 
+#include <limits.h>
 #include <stddef.h>
 
 #include "lua.h"
@@ -55,8 +56,11 @@ static void dumpByte (DumpState *D, int y) {
 }
 
 
-/* dumpInt Buff Size */
-#define DIBS    ((sizeof(size_t) * 8 / 7) + 1)
+/*
+** 'dumpSize' buffer size: each byte can store up to 7 bits. (The "+6"
+** rounds up the division.)
+*/
+#define DIBS    ((sizeof(size_t) * CHAR_BIT + 6) / 7)
 
 static void dumpSize (DumpState *D, size_t x) {
   lu_byte buff[DIBS];

+ 2 - 0
lundump.c

@@ -248,6 +248,8 @@ static void loadDebug (LoadState *S, Proto *f) {
     f->locvars[i].endpc = loadInt(S);
   }
   n = loadInt(S);
+  if (n != 0)  /* does it have debug information? */
+    n = f->sizeupvalues;  /* must be this many */
   for (i = 0; i < n; i++)
     f->upvalues[i].name = loadStringN(S, f);
 }

+ 14 - 0
testes/calls.lua

@@ -342,6 +342,20 @@ do   -- another bug (in 5.4.0)
 end
 
 
+do   -- another bug (since 5.2)
+  -- corrupted binary dump: list of upvalue names is larger than number
+  -- of upvalues, overflowing the array of upvalues.
+  local code =
+   "\x1b\x4c\x75\x61\x54\x00\x19\x93\x0d\x0a\x1a\x0a\x04\x08\x08\x78\x56\z
+    \x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x28\x77\x40\x00\x86\x40\z
+    \x74\x65\x6d\x70\x81\x81\x01\x00\x02\x82\x48\x00\x02\x00\xc7\x00\x01\z
+    \x00\x80\x80\x80\x82\x00\x00\x80\x81\x82\x78\x80\x82\x81\x86\x40\x74\z
+    \x65\x6d\x70"
+
+  assert(load(code))   -- segfaults in previous versions
+end
+
+
 x = string.dump(load("x = 1; return x"))
 a = assert(load(read1(x), nil, "b"))
 assert(a() == 1 and _G.x == 1)