【发布时间】：2021-03-21 10:17:33
【问题描述】：
想知道这对 SQL 注入有多脆弱。我听说使用prepared sql语句可以绕过这个漏洞，但我也听说使用双引号代替单引号也可以防止SQL注入。我不是安全专家，我也不擅长使用 sqlite。此外，我需要在其他地方初始化数据库，并且可能最终使用准备好的语句而不是 sprintf，但我只是不完全确定如何做这些事情中的任何一个。任何帮助是极大的赞赏！谢谢！
bool sql_console_msgs = false;
void QServ::savestats(clientinfo *ci)
{
if(enable_sqlite_db) {
sqlite3 *db;
char *zErrMsg = 0;
int rc;
const char *sql;
bool name_match;
const char* player_database_names;
char *p_name = ci->name;
char *p_ip = ci->ip;
rc = sqlite3_open("playerinfo.db", &db);
if( rc ){
fprintf(stderr, "Can't open database: %s\n", sqlite3_errmsg(db));
exit(0);
}else{
if(sql_console_msgs) fprintf(stdout, "Opened database successfully\n");
}
if( rc != SQLITE_OK ){
fprintf(stderr, "SQL Database Error: %s\n", zErrMsg);
sqlite3_free(zErrMsg);
}else{
sqlite3_stmt *stmt;
defformatstring(sqlstrprep)("SELECT NAME FROM PLAYERINFO");
rc = sqlite3_prepare_v2(db, sqlstrprep, -1, &stmt, NULL);
while ((rc = sqlite3_step(stmt)) == SQLITE_ROW) {
player_database_names = reinterpret_cast<const char*>(sqlite3_column_text(stmt, 0));
if(!strcmp(player_database_names, p_name)) name_match = true;
else name_match = false;
}
}
sql = "CREATE TABLE IF NOT EXISTS PLAYERINFO(" \
"NAME TEXT NOT NULL," \
"FRAGS INT NOT NULL," \
"DEATHS INT NOT NULL," \
"FLAGS INT NOT NULL," \
"PASSES INT NOT NULL," \
"IP TEXT NOT NULL," \
"ACCURACY DECIMAL(4, 2) NOT NULL," \
"KPD DECIMAL(4, 2) NOT NULL);";
rc = sqlite3_exec(db, sql, callback, 0, &zErrMsg);
if( rc != SQLITE_OK ){
fprintf(stderr, "SQLITE3 ERROR @ CREATE TABLE IF NOT EXISTS: %s\n", zErrMsg);
sqlite3_free(zErrMsg);
}else{
if(sql_console_msgs) {
if(!name_match) fprintf(stdout, "No previous record found under that name\n");
else fprintf(stdout, "Found name and IP already, updating record instead\n");
}
}
char sqlINSERT[256];
char sqlUPDATE[1000];
int p_frags = ci->state.frags;
int p_deaths = ci->state.deaths;
int p_flags = ci->state.flags;
int p_passes = ci->state.passes;
int p_acc = (ci->state.damage*100)/max(ci->state.shotdamage, 1);
int p_kpd = (ci->state.frags)/max(ci->state.deaths, 1);
//name and ip are different
if(!name_match) {
sprintf(sqlINSERT, "INSERT INTO PLAYERINFO( NAME,FRAGS,DEATHS,FLAGS,PASSES,IP,ACCURACY,KPD ) VALUES ('%s', %d, %d, %d, %d, '%s', %d, %d)",p_name,p_frags,p_deaths,p_flags,p_passes,p_ip,p_acc,p_kpd);
rc = sqlite3_exec(db, sqlINSERT, callback, 0, &zErrMsg);
}
//client name matches db record, update db if new info is > than db info
else if(name_match) {
sprintf(sqlUPDATE,
"UPDATE PLAYERINFO SET FRAGS = %d+(SELECT FRAGS FROM PLAYERINFO) WHERE NAME = '%s';" \
"UPDATE PLAYERINFO SET DEATHS = %d+(SELECT DEATHS FROM PLAYERINFO) WHERE NAME = '%s';" \
"UPDATE PLAYERINFO SET FLAGS = %d+(SELECT FLAGS FROM PLAYERINFO) WHERE NAME = '%s';" \
"UPDATE PLAYERINFO SET PASSES = %d+(SELECT PASSES FROM PLAYERINFO) WHERE NAME = '%s';" \
"UPDATE PLAYERINFO SET ACCURACY = %d+(SELECT PASSES FROM PLAYERINFO) WHERE NAME = '%s';" \
"UPDATE PLAYERINFO SET KPD = %d+(SELECT PASSES FROM PLAYERINFO) WHERE NAME = '%s';",
ci->state.frags, ci->name, ci->state.deaths, ci->name, ci->state.flags, ci->name, ci->state.passes, ci->name, p_acc, ci->name, p_kpd, ci->name);
rc = sqlite3_exec(db, sqlUPDATE, callback, 0, &zErrMsg);
}
if( rc != SQLITE_OK ){
fprintf(stderr, "SQLITE3 ERROR @ INSERT & UPDATE: %s\n", zErrMsg);
sqlite3_free(zErrMsg);
}else{
if(sql_console_msgs) fprintf(stdout, "Playerinfo modified\n");
}
sqlite3_close(db);
}
}
void QServ::getstats(clientinfo *ci)
{
if(enable_sqlite_db) {
sqlite3 *db;
char *zErrMsg = 0;
int rc;
char *sql;
const char* data = "Callback function called";
rc = sqlite3_open("playerinfo.db", &db);
if( rc ){
fprintf(stderr, "Can't open database: %s\n", sqlite3_errmsg(db));
exit(0);
}
if( rc != SQLITE_OK ){
fprintf(stderr, "SQL Database Error: %s\n", zErrMsg);
sqlite3_free(zErrMsg);
}else{
sqlite3_stmt *stmt;
defformatstring(sqlstrprep)("SELECT NAME,FRAGS,ACCURACY,KPD FROM PLAYERINFO WHERE NAME == '%s';", ci->name);
rc = sqlite3_prepare_v2(db, sqlstrprep, -1, &stmt, NULL);
bool necho = false;
while ((rc = sqlite3_step(stmt)) == SQLITE_ROW) {
const char* name = reinterpret_cast<const char*>(sqlite3_column_text(stmt, 0));
const char* allfrags = reinterpret_cast<const char*>(sqlite3_column_text(stmt, 1));
const char* avgacc = reinterpret_cast<const char*>(sqlite3_column_text(stmt, 2));
const char* avgkpd = reinterpret_cast<const char*>(sqlite3_column_text(stmt, 3));
if(!necho) {
if(avgacc == NULL) out(ECHO_SERV, "Name: \f0%s\f7, Total Frags: \f3%s\f7, Average KPD: \f6%s", name, allfrags, avgkpd);
else if(avgkpd == NULL) out(ECHO_SERV, "Name: \f0%s\f7, Total Frags: \f3%s\f7, Average Accuracy: \f2%s%%", name, allfrags, avgacc);
else out(ECHO_SERV, "Name: \f0%s\f7, Total Frags: \f3%s\f7, Average Accuracy: \f2%s%%\f7, Average KPD: \f6%s", name,allfrags,avgacc,avgkpd);
necho = true;
}
}
}
sqlite3_close(db);
}
}
void QServ::getnames(clientinfo *ci) {
if(enable_sqlite_db) {
sqlite3_stmt *stmt3;
sqlite3 *db;
int rc;
rc = sqlite3_open("playerinfo.db", &db);
defformatstring(sqlstrprep3)("SELECT group_concat(NAME, ', ') FROM PLAYERINFO WHERE IP == '%s';", ci->ip);
rc = sqlite3_prepare_v2(db, sqlstrprep3, -1, &stmt3, NULL);
while ((rc = sqlite3_step(stmt3)) == SQLITE_ROW) {
std::string names(reinterpret_cast<const char*>(sqlite3_column_text(stmt3, 0)));
defformatstring(nmsg)("Names from IP \f2%s\f7: %s", ci->ip, names.c_str());
out(ECHO_SERV, nmsg);
}
sqlite3_close(db);
}
}
【问题讨论】：
-
真正的问题：你了解什么是 SQL 注入以及为什么它会很危险吗？
-
@Tas 我相信它会破坏整个 playerinfo.db 数据库。
标签： c++ sqlite sql-injection