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DPP: Use dpp_bn2bin_pad() helper to simplify code

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Number of places writing BIGNUM values with left-padding were open
coding this helper functionality unnecessarily.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
This commit is contained in:
Jouni Malinen 2017-11-03 16:49:48 +02:00 committed by Jouni Malinen
parent dab5642089
commit fc0efa2a1e
1 changed files with 30 additions and 95 deletions
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125
src/common/dpp.c
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@ -339,6 +339,20 @@ static int dpp_hmac(size_t hash_len, const u8 *key, size_t key_len,
} }
static int dpp_bn2bin_pad(const BIGNUM *bn, u8 *pos, size_t len)
{
int num_bytes, offset;
num_bytes = BN_num_bytes(bn);
if ((size_t) num_bytes > len)
return -1;
offset = len - num_bytes;
os_memset(pos, 0, offset);
BN_bn2bin(bn, pos + offset);
return 0;
}
static struct wpabuf * dpp_get_pubkey_point(EVP_PKEY *pkey, int prefix) static struct wpabuf * dpp_get_pubkey_point(EVP_PKEY *pkey, int prefix)
{ {
int len, res; int len, res;
@ -2050,7 +2064,6 @@ static int dpp_auth_derive_l_responder(struct dpp_authentication *auth)
BIGNUM *lx, *sum, *q; BIGNUM *lx, *sum, *q;
const BIGNUM *bR_bn, *pR_bn; const BIGNUM *bR_bn, *pR_bn;
int ret = -1; int ret = -1;
int num_bytes, offset;
/* L = ((bR + pR) modulo q) * BI */ /* L = ((bR + pR) modulo q) * BI */
@ -2090,16 +2103,8 @@ static int dpp_auth_derive_l_responder(struct dpp_authentication *auth)
goto fail; goto fail;
} }
num_bytes = BN_num_bytes(lx); if (dpp_bn2bin_pad(lx, auth->Lx, auth->secret_len) < 0)
if ((size_t) num_bytes > auth->secret_len)
goto fail; goto fail;
if (auth->secret_len > (size_t) num_bytes)
offset = auth->secret_len - num_bytes;
else
offset = 0;
os_memset(auth->Lx, 0, offset);
BN_bn2bin(lx, auth->Lx + offset);
wpa_hexdump_key(MSG_DEBUG, "DPP: L.x", auth->Lx, auth->secret_len); wpa_hexdump_key(MSG_DEBUG, "DPP: L.x", auth->Lx, auth->secret_len);
ret = 0; ret = 0;
fail: fail:
@ -2125,7 +2130,6 @@ static int dpp_auth_derive_l_initiator(struct dpp_authentication *auth)
BIGNUM *lx; BIGNUM *lx;
const BIGNUM *bI_bn; const BIGNUM *bI_bn;
int ret = -1; int ret = -1;
int num_bytes, offset;
/* L = bI * (BR + PR) */ /* L = bI * (BR + PR) */
@ -2160,16 +2164,8 @@ static int dpp_auth_derive_l_initiator(struct dpp_authentication *auth)
goto fail; goto fail;
} }
num_bytes = BN_num_bytes(lx); if (dpp_bn2bin_pad(lx, auth->Lx, auth->secret_len) < 0)
if ((size_t) num_bytes > auth->secret_len)
goto fail; goto fail;
if (auth->secret_len > (size_t) num_bytes)
offset = auth->secret_len - num_bytes;
else
offset = 0;
os_memset(auth->Lx, 0, offset);
BN_bn2bin(lx, auth->Lx + offset);
wpa_hexdump_key(MSG_DEBUG, "DPP: L.x", auth->Lx, auth->secret_len); wpa_hexdump_key(MSG_DEBUG, "DPP: L.x", auth->Lx, auth->secret_len);
ret = 0; ret = 0;
fail: fail:
@ -3441,20 +3437,6 @@ dpp_build_conf_start(struct dpp_authentication *auth,
} }
static int dpp_bn2bin_pad(const BIGNUM *bn, u8 *pos, size_t len)
{
int num_bytes, offset;
num_bytes = BN_num_bytes(bn);
if ((size_t) num_bytes > len)
return -1;
offset = len - num_bytes;
os_memset(pos, 0, offset);
BN_bn2bin(bn, pos + offset);
return 0;
}
static int dpp_build_jwk(struct wpabuf *buf, const char *name, EVP_PKEY *key, static int dpp_build_jwk(struct wpabuf *buf, const char *name, EVP_PKEY *key,
const char *kid, const struct dpp_curve_params *curve) const char *kid, const struct dpp_curve_params *curve)
{ {
@ -5472,7 +5454,6 @@ static int dpp_test_gen_invalid_key(struct wpabuf *msg,
{ {
BN_CTX *ctx; BN_CTX *ctx;
BIGNUM *x, *y; BIGNUM *x, *y;
int num_bytes, offset;
int ret = -1; int ret = -1;
EC_GROUP *group; EC_GROUP *group;
EC_POINT *point; EC_POINT *point;
@ -5505,25 +5486,11 @@ static int dpp_test_gen_invalid_key(struct wpabuf *msg,
break; break;
} }
num_bytes = BN_num_bytes(x); if (dpp_bn2bin_pad(x, wpabuf_put(msg, curve->prime_len),
if ((size_t) num_bytes > curve->prime_len) curve->prime_len) < 0 ||
dpp_bn2bin_pad(y, wpabuf_put(msg, curve->prime_len),
curve->prime_len) < 0)
goto fail; goto fail;
if (curve->prime_len > (size_t) num_bytes)
offset = curve->prime_len - num_bytes;
else
offset = 0;
os_memset(wpabuf_put(msg, offset), 0, offset);
BN_bn2bin(x, wpabuf_put(msg, num_bytes));
num_bytes = BN_num_bytes(y);
if ((size_t) num_bytes > curve->prime_len)
goto fail;
if (curve->prime_len > (size_t) num_bytes)
offset = curve->prime_len - num_bytes;
else
offset = 0;
os_memset(wpabuf_put(msg, offset), 0, offset);
BN_bn2bin(y, wpabuf_put(msg, num_bytes));
ret = 0; ret = 0;
fail: fail:
@ -5549,7 +5516,6 @@ static struct wpabuf * dpp_pkex_build_exchange_req(struct dpp_pkex *pkex)
struct wpabuf *msg = NULL; struct wpabuf *msg = NULL;
size_t attr_len; size_t attr_len;
const struct dpp_curve_params *curve = pkex->own_bi->curve; const struct dpp_curve_params *curve = pkex->own_bi->curve;
int num_bytes, offset;
wpa_printf(MSG_DEBUG, "DPP: Build PKEX Exchange Request"); wpa_printf(MSG_DEBUG, "DPP: Build PKEX Exchange Request");
@ -5634,27 +5600,12 @@ skip_finite_cyclic_group:
} }
#endif /* CONFIG_TESTING_OPTIONS */ #endif /* CONFIG_TESTING_OPTIONS */
num_bytes = BN_num_bytes(Mx); if (dpp_bn2bin_pad(Mx, wpabuf_put(msg, curve->prime_len),
if ((size_t) num_bytes > curve->prime_len) curve->prime_len) < 0 ||
dpp_bn2bin_pad(Mx, pkex->Mx, curve->prime_len) < 0 ||
dpp_bn2bin_pad(My, wpabuf_put(msg, curve->prime_len),
curve->prime_len) < 0)
goto fail; goto fail;
if (curve->prime_len > (size_t) num_bytes)
offset = curve->prime_len - num_bytes;
else
offset = 0;
os_memset(wpabuf_put(msg, offset), 0, offset);
BN_bn2bin(Mx, wpabuf_put(msg, num_bytes));
os_memset(pkex->Mx, 0, offset);
BN_bn2bin(Mx, pkex->Mx + offset);
num_bytes = BN_num_bytes(My);
if ((size_t) num_bytes > curve->prime_len)
goto fail;
if (curve->prime_len > (size_t) num_bytes)
offset = curve->prime_len - num_bytes;
else
offset = 0;
os_memset(wpabuf_put(msg, offset), 0, offset);
BN_bn2bin(My, wpabuf_put(msg, num_bytes));
out: out:
wpabuf_free(M_buf); wpabuf_free(M_buf);
@ -5718,7 +5669,6 @@ dpp_pkex_build_exchange_resp(struct dpp_pkex *pkex,
{ {
struct wpabuf *msg = NULL; struct wpabuf *msg = NULL;
size_t attr_len; size_t attr_len;
int num_bytes, offset;
const struct dpp_curve_params *curve = pkex->own_bi->curve; const struct dpp_curve_params *curve = pkex->own_bi->curve;
/* Initiator -> Responder: DPP Status, [identifier,] N */ /* Initiator -> Responder: DPP Status, [identifier,] N */
@ -5776,27 +5726,12 @@ skip_status:
} }
#endif /* CONFIG_TESTING_OPTIONS */ #endif /* CONFIG_TESTING_OPTIONS */
num_bytes = BN_num_bytes(Nx); if (dpp_bn2bin_pad(Nx, wpabuf_put(msg, curve->prime_len),
if ((size_t) num_bytes > curve->prime_len) curve->prime_len) < 0 ||
dpp_bn2bin_pad(Nx, pkex->Nx, curve->prime_len) < 0 ||
dpp_bn2bin_pad(Ny, wpabuf_put(msg, curve->prime_len),
curve->prime_len) < 0)
goto fail; goto fail;
if (curve->prime_len > (size_t) num_bytes)
offset = curve->prime_len - num_bytes;
else
offset = 0;
os_memset(wpabuf_put(msg, offset), 0, offset);
BN_bn2bin(Nx, wpabuf_put(msg, num_bytes));
os_memset(pkex->Nx, 0, offset);
BN_bn2bin(Nx, pkex->Nx + offset);
num_bytes = BN_num_bytes(Ny);
if ((size_t) num_bytes > curve->prime_len)
goto fail;
if (curve->prime_len > (size_t) num_bytes)
offset = curve->prime_len - num_bytes;
else
offset = 0;
os_memset(wpabuf_put(msg, offset), 0, offset);
BN_bn2bin(Ny, wpabuf_put(msg, num_bytes));
skip_encrypted_key: skip_encrypted_key:
if (status == DPP_STATUS_BAD_GROUP) { if (status == DPP_STATUS_BAD_GROUP) {