diff options
| -rw-r--r-- | util-src/crypto.c | 27 | ||||
| -rw-r--r-- | util/jwt.lua | 8 |
2 files changed, 21 insertions, 14 deletions
diff --git a/util-src/crypto.c b/util-src/crypto.c index c5ecf9ab..dce1a740 100644 --- a/util-src/crypto.c +++ b/util-src/crypto.c @@ -33,6 +33,9 @@ typedef unsigned __int32 uint32_t; #define luaL_setfuncs(L, R, N) luaL_register(L, NULL, R) #endif +/* The max size of an encoded 'R' or 'S' value. P-521 = 521 bits = 66 bytes */ +#define MAX_ECDSA_SIG_INT_BYTES 66 + #include "managed_pointer.h" #define PKEY_MT_TAG "util.crypto key" @@ -433,10 +436,15 @@ static int Lparse_ecdsa_signature(lua_State *L) { ECDSA_SIG *sig; size_t sig_der_len; const unsigned char *sig_der = (unsigned char*)luaL_checklstring(L, 1, &sig_der_len); + const size_t sig_int_bytes = luaL_checkinteger(L, 2); const BIGNUM *r, *s; - unsigned char rb[32]; - unsigned char sb[32]; int rlen, slen; + unsigned char rb[MAX_ECDSA_SIG_INT_BYTES]; + unsigned char sb[MAX_ECDSA_SIG_INT_BYTES]; + + if(sig_int_bytes > MAX_ECDSA_SIG_INT_BYTES) { + luaL_error(L, "requested signature size exceeds supported limit"); + } sig = d2i_ECDSA_SIG(NULL, &sig_der, sig_der_len); @@ -447,17 +455,14 @@ static int Lparse_ecdsa_signature(lua_State *L) { ECDSA_SIG_get0(sig, &r, &s); - rlen = BN_num_bytes(r); - slen = BN_num_bytes(s); + rlen = BN_bn2binpad(r, rb, sig_int_bytes); + slen = BN_bn2binpad(s, sb, sig_int_bytes); - if (rlen > 32 || slen > 32) { + if (rlen == -1 || slen == -1) { ECDSA_SIG_free(sig); - luaL_error(L, "unexpectedly large signature integers"); + luaL_error(L, "encoded integers exceed requested size"); } - BN_bn2bin(r, rb); - BN_bn2bin(s, sb); - ECDSA_SIG_free(sig); lua_pushlstring(L, (const char*)rb, rlen); @@ -485,7 +490,9 @@ static int Lbuild_ecdsa_signature(lua_State *L) { luaL_buffinit(L, &sigbuf); - unsigned char *buffer = (unsigned char*)luaL_prepbuffsize(&sigbuf, rlen+slen+32); + /* DER structure of an ECDSA signature has 7 bytes plus the integers themselves, + which may gain an extra byte once encoded */ + unsigned char *buffer = (unsigned char*)luaL_prepbuffsize(&sigbuf, (rlen+1)+(slen+1)+7); int len = i2d_ECDSA_SIG(sig, &buffer); luaL_addsize(&sigbuf, len); luaL_pushresult(&sigbuf); diff --git a/util/jwt.lua b/util/jwt.lua index 5c74850a..1c7daf12 100644 --- a/util/jwt.lua +++ b/util/jwt.lua @@ -135,21 +135,21 @@ local function new_rsa_algorithm(name) end -- ES*** -local function new_ecdsa_algorithm(name, c_sign, c_verify) +local function new_ecdsa_algorithm(name, c_sign, c_verify, sig_bytes) local function encode_ecdsa_sig(der_sig) - local r, s = crypto.parse_ecdsa_signature(der_sig); + local r, s = crypto.parse_ecdsa_signature(der_sig, sig_bytes); return r..s; end local function decode_ecdsa_sig(jwk_sig) - return crypto.build_ecdsa_signature(jwk_sig:sub(1, 32), jwk_sig:sub(33, 64)); + return crypto.build_ecdsa_signature(jwk_sig:sub(1, sig_bytes), jwk_sig:sub(sig_bytes+1, sig_bytes*2)); end return new_crypto_algorithm(name, "id-ecPublicKey", c_sign, c_verify, encode_ecdsa_sig, decode_ecdsa_sig); end local algorithms = { HS256 = new_hmac_algorithm("HS256"), HS384 = new_hmac_algorithm("HS384"), HS512 = new_hmac_algorithm("HS512"); - ES256 = new_ecdsa_algorithm("ES256", crypto.ecdsa_sha256_sign, crypto.ecdsa_sha256_verify); + ES256 = new_ecdsa_algorithm("ES256", crypto.ecdsa_sha256_sign, crypto.ecdsa_sha256_verify, 32); RS256 = new_rsa_algorithm("RS256"), RS384 = new_rsa_algorithm("RS384"), RS512 = new_rsa_algorithm("RS512"); PS256 = new_rsa_algorithm("PS256"), PS384 = new_rsa_algorithm("PS384"), PS512 = new_rsa_algorithm("PS512"); }; |