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crypto: lib/mpi - Add error checks to extension

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The remaining functions added by commit
a8ea8bdd9d did not check for memory
allocation errors.  Add the checks and change the API to allow errors
to be returned.

Fixes: a8ea8bdd9d ("lib/mpi: Extend the MPI library")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Herbert Xu 2024-08-10 14:20:57 +08:00
parent fca5cb4dd2
commit 8e3a67f2de
8 changed files with 128 additions and 58 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
include/linux/mpi.h
View File

@ -59,7 +59,7 @@ int mpi_write_to_sgl(MPI a, struct scatterlist *sg, unsigned nbytes,
int *sign);
/*-- mpi-mod.c --*/
void mpi_mod(MPI rem, MPI dividend, MPI divisor);
int mpi_mod(MPI rem, MPI dividend, MPI divisor);
/*-- mpi-pow.c --*/
int mpi_powm(MPI res, MPI base, MPI exp, MPI mod);
@ -75,22 +75,22 @@ int mpi_sub_ui(MPI w, MPI u, unsigned long vval);
void mpi_normalize(MPI a);
unsigned mpi_get_nbits(MPI a);
int mpi_test_bit(MPI a, unsigned int n);
void mpi_set_bit(MPI a, unsigned int n);
void mpi_rshift(MPI x, MPI a, unsigned int n);
int mpi_set_bit(MPI a, unsigned int n);
int mpi_rshift(MPI x, MPI a, unsigned int n);
/*-- mpi-add.c --*/
void mpi_add(MPI w, MPI u, MPI v);
void mpi_sub(MPI w, MPI u, MPI v);
void mpi_addm(MPI w, MPI u, MPI v, MPI m);
void mpi_subm(MPI w, MPI u, MPI v, MPI m);
int mpi_add(MPI w, MPI u, MPI v);
int mpi_sub(MPI w, MPI u, MPI v);
int mpi_addm(MPI w, MPI u, MPI v, MPI m);
int mpi_subm(MPI w, MPI u, MPI v, MPI m);
/*-- mpi-mul.c --*/
void mpi_mul(MPI w, MPI u, MPI v);
void mpi_mulm(MPI w, MPI u, MPI v, MPI m);
int mpi_mul(MPI w, MPI u, MPI v);
int mpi_mulm(MPI w, MPI u, MPI v, MPI m);
/*-- mpi-div.c --*/
void mpi_tdiv_r(MPI rem, MPI num, MPI den);
void mpi_fdiv_r(MPI rem, MPI dividend, MPI divisor);
int mpi_tdiv_r(MPI rem, MPI num, MPI den);
int mpi_fdiv_r(MPI rem, MPI dividend, MPI divisor);
/* inline functions */

38
lib/crypto/mpi/mpi-add.c
View File

@ -13,11 +13,12 @@
#include "mpi-internal.h"
void mpi_add(MPI w, MPI u, MPI v)
int mpi_add(MPI w, MPI u, MPI v)
{
mpi_ptr_t wp, up, vp;
mpi_size_t usize, vsize, wsize;
int usign, vsign, wsign;
int err;
if (u->nlimbs < v->nlimbs) { /* Swap U and V. */
usize = v->nlimbs;
@ -25,7 +26,9 @@ void mpi_add(MPI w, MPI u, MPI v)
vsize = u->nlimbs;
vsign = u->sign;
wsize = usize + 1;
RESIZE_IF_NEEDED(w, wsize);
err = RESIZE_IF_NEEDED(w, wsize);
if (err)
return err;
/* These must be after realloc (u or v may be the same as w). */
up = v->d;
vp = u->d;
@ -35,7 +38,9 @@ void mpi_add(MPI w, MPI u, MPI v)
vsize = v->nlimbs;
vsign = v->sign;
wsize = usize + 1;
RESIZE_IF_NEEDED(w, wsize);
err = RESIZE_IF_NEEDED(w, wsize);
if (err)
return err;
/* These must be after realloc (u or v may be the same as w). */
up = u->d;
vp = v->d;
@ -77,28 +82,37 @@ void mpi_add(MPI w, MPI u, MPI v)
w->nlimbs = wsize;
w->sign = wsign;
return 0;
}
EXPORT_SYMBOL_GPL(mpi_add);
void mpi_sub(MPI w, MPI u, MPI v)
int mpi_sub(MPI w, MPI u, MPI v)
{
MPI vv = mpi_copy(v);
int err;
MPI vv;
vv = mpi_copy(v);
if (!vv)
return -ENOMEM;
vv->sign = !vv->sign;
mpi_add(w, u, vv);
err = mpi_add(w, u, vv);
mpi_free(vv);
return err;
}
EXPORT_SYMBOL_GPL(mpi_sub);
void mpi_addm(MPI w, MPI u, MPI v, MPI m)
int mpi_addm(MPI w, MPI u, MPI v, MPI m)
{
mpi_add(w, u, v);
mpi_mod(w, w, m);
return mpi_add(w, u, v) ?:
mpi_mod(w, w, m);
}
EXPORT_SYMBOL_GPL(mpi_addm);
void mpi_subm(MPI w, MPI u, MPI v, MPI m)
int mpi_subm(MPI w, MPI u, MPI v, MPI m)
{
mpi_sub(w, u, v);
mpi_mod(w, w, m);
return mpi_sub(w, u, v) ?:
mpi_mod(w, w, m);
}
EXPORT_SYMBOL_GPL(mpi_subm);

25
lib/crypto/mpi/mpi-bit.c
View File

@ -76,9 +76,10 @@ EXPORT_SYMBOL_GPL(mpi_test_bit);
/****************
* Set bit N of A.
*/
void mpi_set_bit(MPI a, unsigned int n)
int mpi_set_bit(MPI a, unsigned int n)
{
unsigned int i, limbno, bitno;
int err;
limbno = n / BITS_PER_MPI_LIMB;
bitno = n % BITS_PER_MPI_LIMB;
@ -86,27 +87,31 @@ void mpi_set_bit(MPI a, unsigned int n)
if (limbno >= a->nlimbs) {
for (i = a->nlimbs; i < a->alloced; i++)
a->d[i] = 0;
mpi_resize(a, limbno+1);
err = mpi_resize(a, limbno+1);
if (err)
return err;
a->nlimbs = limbno+1;
}
a->d[limbno] |= (A_LIMB_1<<bitno);
return 0;
}
/*
* Shift A by N bits to the right.
*/
void mpi_rshift(MPI x, MPI a, unsigned int n)
int mpi_rshift(MPI x, MPI a, unsigned int n)
{
mpi_size_t xsize;
unsigned int i;
unsigned int nlimbs = (n/BITS_PER_MPI_LIMB);
unsigned int nbits = (n%BITS_PER_MPI_LIMB);
int err;
if (x == a) {
/* In-place operation. */
if (nlimbs >= x->nlimbs) {
x->nlimbs = 0;
return;
return 0;
}
if (nlimbs) {
@ -121,7 +126,9 @@ void mpi_rshift(MPI x, MPI a, unsigned int n)
/* Copy and shift by more or equal bits than in a limb. */
xsize = a->nlimbs;
x->sign = a->sign;
RESIZE_IF_NEEDED(x, xsize);
err = RESIZE_IF_NEEDED(x, xsize);
if (err)
return err;
x->nlimbs = xsize;
for (i = 0; i < a->nlimbs; i++)
x->d[i] = a->d[i];
@ -129,7 +136,7 @@ void mpi_rshift(MPI x, MPI a, unsigned int n)
if (nlimbs >= x->nlimbs) {
x->nlimbs = 0;
return;
return 0;
}
for (i = 0; i < x->nlimbs - nlimbs; i++)
@ -143,7 +150,9 @@ void mpi_rshift(MPI x, MPI a, unsigned int n)
/* Copy and shift by less than bits in a limb. */
xsize = a->nlimbs;
x->sign = a->sign;
RESIZE_IF_NEEDED(x, xsize);
err = RESIZE_IF_NEEDED(x, xsize);
if (err)
return err;
x->nlimbs = xsize;
if (xsize) {
@ -159,5 +168,7 @@ void mpi_rshift(MPI x, MPI a, unsigned int n)
}
}
MPN_NORMALIZE(x->d, x->nlimbs);
return 0;
}
EXPORT_SYMBOL_GPL(mpi_rshift);

55
lib/crypto/mpi/mpi-div.c
View File

@ -14,12 +14,13 @@
#include "mpi-internal.h"
#include "longlong.h"
void mpi_tdiv_qr(MPI quot, MPI rem, MPI num, MPI den);
int mpi_tdiv_qr(MPI quot, MPI rem, MPI num, MPI den);
void mpi_fdiv_r(MPI rem, MPI dividend, MPI divisor)
int mpi_fdiv_r(MPI rem, MPI dividend, MPI divisor)
{
int divisor_sign = divisor->sign;
MPI temp_divisor = NULL;
int err;
/* We need the original value of the divisor after the remainder has been
* preliminary calculated. We have to copy it to temporary space if it's
@ -27,16 +28,22 @@ void mpi_fdiv_r(MPI rem, MPI dividend, MPI divisor)
*/
if (rem == divisor) {
temp_divisor = mpi_copy(divisor);
if (!temp_divisor)
return -ENOMEM;
divisor = temp_divisor;
}
mpi_tdiv_r(rem, dividend, divisor);
err = mpi_tdiv_r(rem, dividend, divisor);
if (err)
goto free_temp_divisor;
if (((divisor_sign?1:0) ^ (dividend->sign?1:0)) && rem->nlimbs)
mpi_add(rem, rem, divisor);
err = mpi_add(rem, rem, divisor);
if (temp_divisor)
mpi_free(temp_divisor);
free_temp_divisor:
mpi_free(temp_divisor);
return err;
}
/* If den == quot, den needs temporary storage.
@ -46,12 +53,12 @@ void mpi_fdiv_r(MPI rem, MPI dividend, MPI divisor)
* i.e no extra storage should be allocated.
*/
void mpi_tdiv_r(MPI rem, MPI num, MPI den)
int mpi_tdiv_r(MPI rem, MPI num, MPI den)
{
mpi_tdiv_qr(NULL, rem, num, den);
return mpi_tdiv_qr(NULL, rem, num, den);
}
void mpi_tdiv_qr(MPI quot, MPI rem, MPI num, MPI den)
int mpi_tdiv_qr(MPI quot, MPI rem, MPI num, MPI den)
{
mpi_ptr_t np, dp;
mpi_ptr_t qp, rp;
@ -64,13 +71,16 @@ void mpi_tdiv_qr(MPI quot, MPI rem, MPI num, MPI den)
mpi_limb_t q_limb;
mpi_ptr_t marker[5];
int markidx = 0;
int err;
/* Ensure space is enough for quotient and remainder.
* We need space for an extra limb in the remainder, because it's
* up-shifted (normalized) below.
*/
rsize = nsize + 1;
mpi_resize(rem, rsize);
err = mpi_resize(rem, rsize);
if (err)
return err;
qsize = rsize - dsize; /* qsize cannot be bigger than this. */
if (qsize <= 0) {
@ -86,11 +96,14 @@ void mpi_tdiv_qr(MPI quot, MPI rem, MPI num, MPI den)
quot->nlimbs = 0;
quot->sign = 0;
}
return;
return 0;
}
if (quot)
mpi_resize(quot, qsize);
if (quot) {
err = mpi_resize(quot, qsize);
if (err)
return err;
}
/* Read pointers here, when reallocation is finished. */
np = num->d;
@ -112,10 +125,10 @@ void mpi_tdiv_qr(MPI quot, MPI rem, MPI num, MPI den)
rsize = rlimb != 0?1:0;
rem->nlimbs = rsize;
rem->sign = sign_remainder;
return;
return 0;
}
err = -ENOMEM;
if (quot) {
qp = quot->d;
/* Make sure QP and NP point to different objects. Otherwise the
@ -123,6 +136,8 @@ void mpi_tdiv_qr(MPI quot, MPI rem, MPI num, MPI den)
*/
if (qp == np) { /* Copy NP object to temporary space. */
np = marker[markidx++] = mpi_alloc_limb_space(nsize);
if (!np)
goto out_free_marker;
MPN_COPY(np, qp, nsize);
}
} else /* Put quotient at top of remainder. */
@ -143,6 +158,8 @@ void mpi_tdiv_qr(MPI quot, MPI rem, MPI num, MPI den)
* the original contents of the denominator.
*/
tp = marker[markidx++] = mpi_alloc_limb_space(dsize);
if (!tp)
goto out_free_marker;
mpihelp_lshift(tp, dp, dsize, normalization_steps);
dp = tp;
@ -164,6 +181,8 @@ void mpi_tdiv_qr(MPI quot, MPI rem, MPI num, MPI den)
mpi_ptr_t tp;
tp = marker[markidx++] = mpi_alloc_limb_space(dsize);
if (!tp)
goto out_free_marker;
MPN_COPY(tp, dp, dsize);
dp = tp;
}
@ -198,8 +217,14 @@ void mpi_tdiv_qr(MPI quot, MPI rem, MPI num, MPI den)
rem->nlimbs = rsize;
rem->sign = sign_remainder;
err = 0;
out_free_marker:
while (markidx) {
markidx--;
mpi_free_limb_space(marker[markidx]);
}
return err;
}

11
lib/crypto/mpi/mpi-internal.h
View File

@ -52,11 +52,12 @@
typedef mpi_limb_t *mpi_ptr_t; /* pointer to a limb */
typedef int mpi_size_t; /* (must be a signed type) */
#define RESIZE_IF_NEEDED(a, b) \
do { \
if ((a)->alloced < (b)) \
mpi_resize((a), (b)); \
} while (0)
static inline int RESIZE_IF_NEEDED(MPI a, unsigned b)
{
if (a->alloced < b)
return mpi_resize(a, b);
return 0;
}
/* Copy N limbs from S to D. */
#define MPN_COPY(d, s, n) \

4
lib/crypto/mpi/mpi-mod.c
View File

@ -7,7 +7,7 @@
#include "mpi-internal.h"
void mpi_mod(MPI rem, MPI dividend, MPI divisor)
int mpi_mod(MPI rem, MPI dividend, MPI divisor)
{
mpi_fdiv_r(rem, dividend, divisor);
return mpi_fdiv_r(rem, dividend, divisor);
}

29
lib/crypto/mpi/mpi-mul.c
View File

@ -13,7 +13,7 @@
#include "mpi-internal.h"
void mpi_mul(MPI w, MPI u, MPI v)
int mpi_mul(MPI w, MPI u, MPI v)
{
mpi_size_t usize, vsize, wsize;
mpi_ptr_t up, vp, wp;
@ -21,6 +21,7 @@ void mpi_mul(MPI w, MPI u, MPI v)
int usign, vsign, sign_product;
int assign_wp = 0;
mpi_ptr_t tmp_limb = NULL;
int err;
if (u->nlimbs < v->nlimbs) {
/* Swap U and V. */
@ -46,15 +47,21 @@ void mpi_mul(MPI w, MPI u, MPI v)
if (w->alloced < wsize) {
if (wp == up || wp == vp) {
wp = mpi_alloc_limb_space(wsize);
if (!wp)
return -ENOMEM;
assign_wp = 1;
} else {
mpi_resize(w, wsize);
err = mpi_resize(w, wsize);
if (err)
return err;
wp = w->d;
}
} else { /* Make U and V not overlap with W. */
if (wp == up) {
/* W and U are identical. Allocate temporary space for U. */
up = tmp_limb = mpi_alloc_limb_space(usize);
if (!up)
return -ENOMEM;
/* Is V identical too? Keep it identical with U. */
if (wp == vp)
vp = up;
@ -63,6 +70,8 @@ void mpi_mul(MPI w, MPI u, MPI v)
} else if (wp == vp) {
/* W and V are identical. Allocate temporary space for V. */
vp = tmp_limb = mpi_alloc_limb_space(vsize);
if (!vp)
return -ENOMEM;
/* Copy to the temporary space. */
MPN_COPY(vp, wp, vsize);
}
@ -71,7 +80,12 @@ void mpi_mul(MPI w, MPI u, MPI v)
if (!vsize)
wsize = 0;
else {
mpihelp_mul(wp, up, usize, vp, vsize, &cy);
err = mpihelp_mul(wp, up, usize, vp, vsize, &cy);
if (err) {
if (assign_wp)
mpi_free_limb_space(wp);
goto free_tmp_limb;
}
wsize -= cy ? 0:1;
}
@ -79,14 +93,17 @@ void mpi_mul(MPI w, MPI u, MPI v)
mpi_assign_limb_space(w, wp, wsize);
w->nlimbs = wsize;
w->sign = sign_product;
free_tmp_limb:
if (tmp_limb)
mpi_free_limb_space(tmp_limb);
return err;
}
EXPORT_SYMBOL_GPL(mpi_mul);
void mpi_mulm(MPI w, MPI u, MPI v, MPI m)
int mpi_mulm(MPI w, MPI u, MPI v, MPI m)
{
mpi_mul(w, u, v);
mpi_tdiv_r(w, w, m);
return mpi_mul(w, u, v) ?:
mpi_tdiv_r(w, w, m);
}
EXPORT_SYMBOL_GPL(mpi_mulm);

2
lib/crypto/mpi/mpiutil.c
View File

@ -133,6 +133,8 @@ MPI mpi_copy(MPI a)
if (a) {
b = mpi_alloc(a->nlimbs);
if (!b)
return NULL;
b->nlimbs = a->nlimbs;
b->sign = a->sign;
b->flags = a->flags;