From 83fd8434738b56b77a6019b79c1e5187adafc0d3 Mon Sep 17 00:00:00 2001
From: Evgeniy Kramsakov <evgeniy.kramsakov@demlabs.net>
Date: Sat, 3 Sep 2022 21:54:00 +0300
Subject: [PATCH] [*] Add some checks on overflow in str_to_256 convert. Add
new todos
---
dap-sdk/core/include/dap_math_ops.h | 3 +++
modules/common/dap_chain_common.c | 30 +++++++++++++++++++++++++----
2 files changed, 29 insertions(+), 4 deletions(-)
diff --git a/dap-sdk/core/include/dap_math_ops.h b/dap-sdk/core/include/dap_math_ops.h
index 4d16ade7f3..a751eaae99 100755
--- a/dap-sdk/core/include/dap_math_ops.h
+++ b/dap-sdk/core/include/dap_math_ops.h
@@ -95,6 +95,9 @@ extern const uint128_t uint128_0;
extern const uint128_t uint128_1;
extern const uint256_t uint256_0;
extern const uint256_t uint256_1;
+
+//todo: implement uintX_max
+//extern const uint256_t uint256_max;
extern const uint512_t uint512_0;
static inline uint128_t GET_128_FROM_64(uint64_t n) {
diff --git a/modules/common/dap_chain_common.c b/modules/common/dap_chain_common.c
index 2491c7b8d8..7997039a96 100644
--- a/modules/common/dap_chain_common.c
+++ b/modules/common/dap_chain_common.c
@@ -735,6 +735,7 @@ uint256_t dap_cvt_str_to_uint256(const char *a_256bit_num)
uint256_t l_ret = uint256_0, l_nul = uint256_0;
int l_strlen;
char l_256bit_num[DAP_CHAIN$SZ_MAX256DEC + 1];
+ int overflow_flag = 0;
if (!a_256bit_num) {
@@ -773,11 +774,16 @@ uint256_t dap_cvt_str_to_uint256(const char *a_256bit_num)
memcpy(l_256bit_num, a_256bit_num, l_dot_len);
memcpy(l_256bit_num + l_dot_len, a_256bit_num + l_dot_len + 1, l_exp_len);
int l_zero_cnt = l_exp - l_exp_len;
+ if (l_zero_cnt > DAP_CHAIN$SZ_MAX256DEC) {
+ //todo: need to handle leading zeroes, like 0.000...123e100
+ return log_it(L_ERROR, "Too long number for 256 bit: `%s` (%d > %d)", a_256bit_num, l_strlen, DAP_CHAIN$SZ_MAX256DEC), l_nul;
+ }
size_t l_pos = l_dot_len + l_exp_len;
for (int i = l_zero_cnt; i && l_pos < DAP_CHAIN$SZ_MAX256DEC; i--)
l_256bit_num[l_pos++] = '0';
l_256bit_num[l_pos] = '\0';
l_strlen = l_pos;
+
} else {
//we ahve an decimal string, not sci notation
if ( (l_strlen = strnlen(a_256bit_num, DAP_CHAIN$SZ_MAX256DEC + 1) ) > DAP_CHAIN$SZ_MAX256DEC)
@@ -799,14 +805,22 @@ uint256_t dap_cvt_str_to_uint256(const char *a_256bit_num)
uint256_t l_tmp;
l_tmp.hi = 0;
l_tmp.lo = (uint128_t)c_pow10_double[i].u64[3] * (uint128_t) l_digit;
- SUM_256_256(l_ret, l_tmp, &l_ret);
+ overflow_flag = SUM_256_256(l_ret, l_tmp, &l_ret);
+ if (overflow_flag) {
+ //todo: change string to uint256_max after implementation
+ return log_it(L_ERROR, "Too big number '%s', max number is '%s'", a_256bit_num, "115792089237316195423570985008687907853269984665640564039457584007913129639935"), l_nul;
+ }
// if (l_ret.hi == 0 && l_ret.lo == 0) {
// return l_nul;
// }
uint128_t l_mul = (uint128_t) c_pow10_double[i].u64[2] * (uint128_t) l_digit;
l_tmp.lo = l_mul << 64;
l_tmp.hi = l_mul >> 64;
- SUM_256_256(l_ret, l_tmp, &l_ret);
+ overflow_flag = SUM_256_256(l_ret, l_tmp, &l_ret);
+ if (overflow_flag) {
+ //todo: change string to uint256_max after implementation
+ return log_it(L_ERROR, "Too big number '%s', max number is '%s'", a_256bit_num, "115792089237316195423570985008687907853269984665640564039457584007913129639935"), l_nul;
+ }
if (l_ret.hi == 0 && l_ret.lo == 0) {
return l_nul;
@@ -814,7 +828,11 @@ uint256_t dap_cvt_str_to_uint256(const char *a_256bit_num)
l_tmp.lo = 0;
l_tmp.hi = (uint128_t) c_pow10_double[i].u64[1] * (uint128_t) l_digit;
- SUM_256_256(l_ret, l_tmp, &l_ret);
+ overflow_flag = SUM_256_256(l_ret, l_tmp, &l_ret);
+ if (overflow_flag) {
+ //todo: change string to uint256_max after implementation
+ return log_it(L_ERROR, "Too big number '%s', max number is '%s'", a_256bit_num, "115792089237316195423570985008687907853269984665640564039457584007913129639935"), l_nul;
+ }
if (l_ret.hi == 0 && l_ret.lo == 0) {
return l_nul;
}
@@ -825,7 +843,11 @@ uint256_t dap_cvt_str_to_uint256(const char *a_256bit_num)
return l_nul;
}
l_tmp.hi = l_mul << 64;
- SUM_256_256(l_ret, l_tmp, &l_ret);
+ overflow_flag = SUM_256_256(l_ret, l_tmp, &l_ret);
+ if (overflow_flag) {
+ //todo: change string to uint256_max after implementation
+ return log_it(L_ERROR, "Too big number '%s', max number is '%s'", a_256bit_num, "115792089237316195423570985008687907853269984665640564039457584007913129639935"), l_nul;
+ }
if (l_ret.hi == 0 && l_ret.lo == 0) {
return l_nul;
}
--
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