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Use a securely seeded global PRNG for the VM.

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It's not 2005 anymore.
This commit is contained in:
Mike Pall
2020-06-15 12:21:05 +02:00
parent 34e53736c6
commit a44f53acf5
22 changed files with 411 additions and 174 deletions
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13
src/lj_jit.h
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@@ -438,9 +438,9 @@ typedef struct jit_State {
int32_t framedepth; /* Current frame depth. */
int32_t retdepth; /* Return frame depth (count of RETF). */
uint32_t k32[LJ_K32__MAX]; /* Common 4 byte constants used by backends. */
TValue ksimd[LJ_KSIMD__MAX*2+1]; /* 16 byte aligned SIMD constants. */
TValue k64[LJ_K64__MAX]; /* Common 8 byte constants used by backends. */
uint32_t k32[LJ_K32__MAX]; /* Ditto for 4 byte constants. */
TValue k64[LJ_K64__MAX]; /* Common 8 byte constants. */
IRIns *irbuf; /* Temp. IR instruction buffer. Biased with REF_BIAS. */
IRRef irtoplim; /* Upper limit of instuction buffer (biased). */
@@ -472,7 +472,6 @@ typedef struct jit_State {
HotPenalty penalty[PENALTY_SLOTS]; /* Penalty slots. */
uint32_t penaltyslot; /* Round-robin index into penalty slots. */
uint32_t prngstate; /* PRNG state. */
#ifdef LUAJIT_ENABLE_TABLE_BUMP
RBCHashEntry rbchash[RBCHASH_SLOTS]; /* Reverse bytecode map. */
@@ -516,12 +515,4 @@ jit_State;
#define lj_assertJ(c, ...) ((void)J)
#endif
/* Trivial PRNG e.g. used for penalty randomization. */
static LJ_AINLINE uint32_t LJ_PRNG_BITS(jit_State *J, int bits)
{
/* Yes, this LCG is very weak, but that doesn't matter for our use case. */
J->prngstate = J->prngstate * 1103515245 + 12345;
return J->prngstate >> (32-bits);
}
#endif