using explicit tests for allocation overflow whenever possible

This commit is contained in:
Roberto Ierusalimschy 2017-12-07 16:59:52 -02:00
parent 46bc7f2bf7
commit 7622373033
5 changed files with 80 additions and 46 deletions

28
lmem.c
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@ -1,5 +1,5 @@
/* /*
** $Id: lmem.c,v 1.91 2015/03/06 19:45:54 roberto Exp roberto $ ** $Id: lmem.c,v 1.92 2017/12/06 18:36:31 roberto Exp roberto $
** Interface to Memory Manager ** Interface to Memory Manager
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@ -53,24 +53,26 @@
#define MINSIZEARRAY 4 #define MINSIZEARRAY 4
void *luaM_growaux_ (lua_State *L, void *block, int nelems, int *size, void *luaM_growaux_ (lua_State *L, void *block, int nelems, int *psize,
int size_elems, int limit, const char *what) { int size_elems, int limit, const char *what) {
void *newblock; void *newblock;
int newsize; int size = *psize;
if (nelems + 1 <= *size) /* does one extra element still fit? */ if (nelems + 1 <= size) /* does one extra element still fit? */
return block; /* nothing to be done */ return block; /* nothing to be done */
if (*size >= limit/2) { /* cannot double it? */ if (size >= limit / 2) { /* cannot double it? */
if (*size >= limit) /* cannot grow even a little? */ if (size >= limit) /* cannot grow even a little? */
luaG_runerror(L, "too many %s (limit is %d)", what, limit); luaG_runerror(L, "too many %s (limit is %d)", what, limit);
newsize = limit; /* still have at least one free place */ size = limit; /* still have at least one free place */
} }
else { else {
newsize = (*size)*2; size *= 2;
if (newsize < MINSIZEARRAY) if (size < MINSIZEARRAY)
newsize = MINSIZEARRAY; /* minimum size */ size = MINSIZEARRAY; /* minimum size */
} }
newblock = luaM_reallocv(L, block, *size, newsize, size_elems); /* 'limit' ensures that multiplication will not overflow */
*size = newsize; /* update only when everything else is OK */ newblock = luaM_realloc(L, block, cast(size_t, *psize) * size_elems,
cast(size_t, size) * size_elems);
*psize = size; /* update only when everything else is OK */
return newblock; return newblock;
} }
@ -113,7 +115,7 @@ void luaM_free_ (lua_State *L, void *block, size_t osize) {
/* /*
** generic allocation routine. ** generic allocation routine.
*/ */
void *luaM_realloc_ (lua_State *L, void *block, size_t osize, size_t nsize) { void *luaM_realloc (lua_State *L, void *block, size_t osize, size_t nsize) {
void *newblock; void *newblock;
global_State *g = G(L); global_State *g = G(L);
lua_assert((osize == 0) == (block == NULL)); lua_assert((osize == 0) == (block == NULL));

32
lmem.h
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@ -1,5 +1,5 @@
/* /*
** $Id: lmem.h,v 1.43 2014/12/19 17:26:14 roberto Exp roberto $ ** $Id: lmem.h,v 1.44 2017/12/06 18:36:31 roberto Exp roberto $
** Interface to Memory Manager ** Interface to Memory Manager
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@ -31,36 +31,40 @@
#define luaM_checksize(L,n,e) \ #define luaM_checksize(L,n,e) \
(luaM_testsize(n,e) ? luaM_toobig(L) : cast_void(0)) (luaM_testsize(n,e) ? luaM_toobig(L) : cast_void(0))
/* /*
** This macro reallocs a vector 'b' from 'on' to 'n' elements, where ** Computes the minimum between 'n' and 'MAX_SIZET/sizeof(t)', so that
** each element has size 'e'. In case of arithmetic overflow of the ** the result is not larger than 'n' and cannot overflow a 'size_t'
** product 'n'*'e', it raises an error (calling 'luaM_toobig'). ** when multiplied by the size of type 't'. (Assumes that 'n' is an
** 'int' or 'unsigned int' and that 'int' is not larger than 'size_t'.)
*/ */
#define luaM_reallocv(L,b,on,n,e) \ #define luaM_limitN(n,t) \
(luaM_checksize(L,n,e), \ ((cast(size_t, n) > MAX_SIZET/sizeof(t)) ? (MAX_SIZET/sizeof(t)) : (n))
luaM_realloc_(L, (b), cast(size_t, on)*(e), cast(size_t, n)*(e)))
/* /*
** Arrays of chars do not need any test ** Arrays of chars do not need any test
*/ */
#define luaM_reallocvchar(L,b,on,n) \ #define luaM_reallocvchar(L,b,on,n) \
cast(char *, luaM_realloc_(L, (b), (on)*sizeof(char), (n)*sizeof(char))) cast(char *, luaM_realloc(L, (b), (on)*sizeof(char), (n)*sizeof(char)))
#define luaM_freemem(L, b, s) luaM_free_(L, (b), (s)) #define luaM_freemem(L, b, s) luaM_free_(L, (b), (s))
#define luaM_free(L, b) luaM_free_(L, (b), sizeof(*(b))) #define luaM_free(L, b) luaM_free_(L, (b), sizeof(*(b)))
#define luaM_freearray(L, b, n) luaM_free_(L, (b), (n)*sizeof(*(b))) #define luaM_freearray(L, b, n) luaM_free_(L, (b), (n)*sizeof(*(b)))
#define luaM_new(L,t) cast(t *, luaM_malloc(L, sizeof(t), 0)) #define luaM_new(L,t) cast(t*, luaM_malloc(L, sizeof(t), 0))
#define luaM_newvector(L,n,t) \ #define luaM_newvector(L,n,t) cast(t*, luaM_malloc(L, (n)*sizeof(t), 0))
(luaM_checksize(L,n,sizeof(t)), cast(t *, luaM_malloc(L, (n)*sizeof(t), 0))) #define luaM_newvectorchecked(L,n,t) \
(luaM_checksize(L,n,sizeof(t)), luaM_newvector(L,n,t))
#define luaM_newobject(L,tag,s) luaM_malloc(L, (s), tag) #define luaM_newobject(L,tag,s) luaM_malloc(L, (s), tag)
#define luaM_growvector(L,v,nelems,size,t,limit,e) \ #define luaM_growvector(L,v,nelems,size,t,limit,e) \
((v)=cast(t *, luaM_growaux_(L,v,nelems,&(size),sizeof(t),limit,e))) ((v)=cast(t *, luaM_growaux_(L,v,nelems,&(size),sizeof(t), \
luaM_limitN(limit,t),e)))
#define luaM_reallocvector(L, v,oldn,n,t) \ #define luaM_reallocvector(L, v,oldn,n,t) \
((v)=cast(t *, luaM_reallocv(L, v, oldn, n, sizeof(t)))) ((v)=cast(t *, luaM_realloc(L, v, cast(size_t, oldn) * sizeof(t), \
cast(size_t, n) * sizeof(t))))
#define luaM_shrinkvector(L,v,size,fs,t) \ #define luaM_shrinkvector(L,v,size,fs,t) \
((v)=cast(t *, luaM_shrinkvector_(L, v, &(size), fs, sizeof(t)))) ((v)=cast(t *, luaM_shrinkvector_(L, v, &(size), fs, sizeof(t))))
@ -68,7 +72,7 @@
LUAI_FUNC l_noret luaM_toobig (lua_State *L); LUAI_FUNC l_noret luaM_toobig (lua_State *L);
/* not to be called directly */ /* not to be called directly */
LUAI_FUNC void *luaM_realloc_ (lua_State *L, void *block, size_t oldsize, LUAI_FUNC void *luaM_realloc (lua_State *L, void *block, size_t oldsize,
size_t size); size_t size);
LUAI_FUNC void luaM_free_ (lua_State *L, void *block, size_t osize); LUAI_FUNC void luaM_free_ (lua_State *L, void *block, size_t osize);
LUAI_FUNC void *luaM_growaux_ (lua_State *L, void *block, int nelems, LUAI_FUNC void *luaM_growaux_ (lua_State *L, void *block, int nelems,

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@ -1,5 +1,5 @@
/* /*
** $Id: lstring.c,v 2.57 2017/07/27 13:50:16 roberto Exp roberto $ ** $Id: lstring.c,v 2.58 2017/12/01 16:40:29 roberto Exp roberto $
** String table (keeps all strings handled by Lua) ** String table (keeps all strings handled by Lua)
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@ -31,6 +31,13 @@
#endif #endif
/*
** Maximum size for string table.
*/
#define MAXSTRTB cast_int(luaM_limitN(MAX_INT, TString*))
/* /*
** equality for long strings ** equality for long strings
*/ */
@ -173,7 +180,8 @@ static TString *internshrstr (lua_State *L, const char *str, size_t l) {
return ts; return ts;
} }
} }
if (g->strt.nuse >= g->strt.size && g->strt.size <= MAX_INT/2) { if (g->strt.nuse >= g->strt.size &&
g->strt.size <= MAXSTRTB / 2) {
luaS_resize(L, g->strt.size * 2); luaS_resize(L, g->strt.size * 2);
list = &g->strt.hash[lmod(h, g->strt.size)]; /* recompute with new size */ list = &g->strt.hash[lmod(h, g->strt.size)]; /* recompute with new size */
} }

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@ -1,5 +1,5 @@
/* /*
** $Id: ltable.c,v 2.126 2017/11/08 14:50:23 roberto Exp roberto $ ** $Id: ltable.c,v 2.127 2017/11/23 19:29:04 roberto Exp roberto $
** Lua tables (hash) ** Lua tables (hash)
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@ -40,21 +40,34 @@
/* /*
** Maximum size of array part (MAXASIZE) is 2^MAXABITS. MAXABITS is ** MAXABITS is the largest integer such that MAXASIZE fits in an
** the largest integer such that MAXASIZE fits in an unsigned int. ** unsigned int.
*/ */
#define MAXABITS cast_int(sizeof(int) * CHAR_BIT - 1) #define MAXABITS cast_int(sizeof(int) * CHAR_BIT - 1)
#define MAXASIZE (1u << MAXABITS)
/* /*
** Maximum size of hash part is 2^MAXHBITS. MAXHBITS is the largest ** MAXASIZE is the maximum size of the array part. It is the minimum
** integer such that 2^MAXHBITS fits in a signed int. (Note that the ** between 2^MAXABITS and the maximum size such that, measured in bytes,
** maximum number of elements in a table, 2^MAXABITS + 2^MAXHBITS, still ** it fits in a 'size_t'.
** fits comfortably in an unsigned int.) */
#define MAXASIZE luaM_limitN(1u << MAXABITS, TValue)
/*
** MAXHBITS is the largest integer such that 2^MAXHBITS fits in a
** signed int.
*/ */
#define MAXHBITS (MAXABITS - 1) #define MAXHBITS (MAXABITS - 1)
/*
** MAXHSIZE is the maximum size of the hash part. It is the minimum
** between 2^MAXHBITS and the maximum size such that, measured in bytes,
** it fits in a 'size_t'.
*/
#define MAXHSIZE luaM_limitN(1u << MAXHBITS, Node)
#define hashpow2(t,n) (gnode(t, lmod((n), sizenode(t)))) #define hashpow2(t,n) (gnode(t, lmod((n), sizenode(t))))
#define hashstr(t,str) hashpow2(t, (str)->hash) #define hashstr(t,str) hashpow2(t, (str)->hash)
@ -353,6 +366,13 @@ static void setarrayvector (lua_State *L, Table *t, unsigned int size) {
} }
/*
** Creates an array for the hash part of a table with the given
** size, or reuses the dummy node if size is zero.
** The computation for size overflow is in two steps: the first
** comparison ensures that the shift in the second one does not
** overflow.
*/
static void setnodevector (lua_State *L, Table *t, unsigned int size) { static void setnodevector (lua_State *L, Table *t, unsigned int size) {
if (size == 0) { /* no elements to hash part? */ if (size == 0) { /* no elements to hash part? */
t->node = cast(Node *, dummynode); /* use common 'dummynode' */ t->node = cast(Node *, dummynode); /* use common 'dummynode' */
@ -362,7 +382,7 @@ static void setnodevector (lua_State *L, Table *t, unsigned int size) {
else { else {
int i; int i;
int lsize = luaO_ceillog2(size); int lsize = luaO_ceillog2(size);
if (lsize > MAXHBITS) if (lsize > MAXHBITS || (1u << lsize) > MAXHSIZE)
luaG_runerror(L, "table overflow"); luaG_runerror(L, "table overflow");
size = twoto(lsize); size = twoto(lsize);
t->node = luaM_newvector(L, size, Node); t->node = luaM_newvector(L, size, Node);

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@ -1,5 +1,5 @@
/* /*
** $Id: lundump.c,v 2.47 2017/06/29 15:06:44 roberto Exp roberto $ ** $Id: lundump.c,v 2.48 2017/11/28 11:19:07 roberto Exp roberto $
** load precompiled Lua chunks ** load precompiled Lua chunks
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@ -114,7 +114,7 @@ static TString *LoadString (LoadState *S) {
static void LoadCode (LoadState *S, Proto *f) { static void LoadCode (LoadState *S, Proto *f) {
int n = LoadInt(S); int n = LoadInt(S);
f->code = luaM_newvector(S->L, n, Instruction); f->code = luaM_newvectorchecked(S->L, n, Instruction);
f->sizecode = n; f->sizecode = n;
LoadVector(S, f->code, n); LoadVector(S, f->code, n);
} }
@ -126,7 +126,7 @@ static void LoadFunction(LoadState *S, Proto *f, TString *psource);
static void LoadConstants (LoadState *S, Proto *f) { static void LoadConstants (LoadState *S, Proto *f) {
int i; int i;
int n = LoadInt(S); int n = LoadInt(S);
f->k = luaM_newvector(S->L, n, TValue); f->k = luaM_newvectorchecked(S->L, n, TValue);
f->sizek = n; f->sizek = n;
for (i = 0; i < n; i++) for (i = 0; i < n; i++)
setnilvalue(&f->k[i]); setnilvalue(&f->k[i]);
@ -159,7 +159,7 @@ static void LoadConstants (LoadState *S, Proto *f) {
static void LoadProtos (LoadState *S, Proto *f) { static void LoadProtos (LoadState *S, Proto *f) {
int i; int i;
int n = LoadInt(S); int n = LoadInt(S);
f->p = luaM_newvector(S->L, n, Proto *); f->p = luaM_newvectorchecked(S->L, n, Proto *);
f->sizep = n; f->sizep = n;
for (i = 0; i < n; i++) for (i = 0; i < n; i++)
f->p[i] = NULL; f->p[i] = NULL;
@ -173,7 +173,7 @@ static void LoadProtos (LoadState *S, Proto *f) {
static void LoadUpvalues (LoadState *S, Proto *f) { static void LoadUpvalues (LoadState *S, Proto *f) {
int i, n; int i, n;
n = LoadInt(S); n = LoadInt(S);
f->upvalues = luaM_newvector(S->L, n, Upvaldesc); f->upvalues = luaM_newvectorchecked(S->L, n, Upvaldesc);
f->sizeupvalues = n; f->sizeupvalues = n;
for (i = 0; i < n; i++) for (i = 0; i < n; i++)
f->upvalues[i].name = NULL; f->upvalues[i].name = NULL;
@ -187,18 +187,18 @@ static void LoadUpvalues (LoadState *S, Proto *f) {
static void LoadDebug (LoadState *S, Proto *f) { static void LoadDebug (LoadState *S, Proto *f) {
int i, n; int i, n;
n = LoadInt(S); n = LoadInt(S);
f->lineinfo = luaM_newvector(S->L, n, ls_byte); f->lineinfo = luaM_newvectorchecked(S->L, n, ls_byte);
f->sizelineinfo = n; f->sizelineinfo = n;
LoadVector(S, f->lineinfo, n); LoadVector(S, f->lineinfo, n);
n = LoadInt(S); n = LoadInt(S);
f->abslineinfo = luaM_newvector(S->L, n, AbsLineInfo); f->abslineinfo = luaM_newvectorchecked(S->L, n, AbsLineInfo);
f->sizeabslineinfo = n; f->sizeabslineinfo = n;
for (i = 0; i < n; i++) { for (i = 0; i < n; i++) {
f->abslineinfo[i].pc = LoadInt(S); f->abslineinfo[i].pc = LoadInt(S);
f->abslineinfo[i].line = LoadInt(S); f->abslineinfo[i].line = LoadInt(S);
} }
n = LoadInt(S); n = LoadInt(S);
f->locvars = luaM_newvector(S->L, n, LocVar); f->locvars = luaM_newvectorchecked(S->L, n, LocVar);
f->sizelocvars = n; f->sizelocvars = n;
for (i = 0; i < n; i++) for (i = 0; i < n; i++)
f->locvars[i].varname = NULL; f->locvars[i].varname = NULL;