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Bug: Negation in 'luaV_shiftr' may overflow 

Negation of an unchecked lua_Integer overflows with mininteger.
This commit is contained in:
Roberto Ierusalimschy 2021-07-22 13:44:53 -03:00
parent 8a32e0aa4a
commit 62fb934427
2 changed files with 6 additions and 1 deletions
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2
lvm.c
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@ -766,7 +766,7 @@ lua_Number luaV_modf (lua_State *L, lua_Number m, lua_Number n) {
/* /*
** Shift left operation. (Shift right just negates 'y'.) ** Shift left operation. (Shift right just negates 'y'.)
*/ */
#define luaV_shiftr(x,y) luaV_shiftl(x,-(y)) #define luaV_shiftr(x,y) luaV_shiftl(x,intop(-, 0, y))
lua_Integer luaV_shiftl (lua_Integer x, lua_Integer y) { lua_Integer luaV_shiftl (lua_Integer x, lua_Integer y) {
if (y < 0) { /* shift right? */ if (y < 0) { /* shift right? */

5
testes/bitwise.lua
View File

@ -45,6 +45,11 @@ assert(-1 >> numbits == 0 and
-1 << numbits == 0 and -1 << numbits == 0 and
-1 << -numbits == 0) -1 << -numbits == 0)
assert(1 >> math.mininteger == 0)
assert(1 >> math.maxinteger == 0)
assert(1 << math.mininteger == 0)
assert(1 << math.maxinteger == 0)
assert((2^30 - 1) << 2^30 == 0) assert((2^30 - 1) << 2^30 == 0)
assert((2^30 - 1) >> 2^30 == 0) assert((2^30 - 1) >> 2^30 == 0)