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Added a simple checksum for stage metadata to fail quickly if garbage is detected

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This commit is contained in:
Andrei "Akari" Alexeyev 2017-02-09 02:55:01 +02:00
parent f2386657f5
commit b0da5a407c
2 changed files with 30 additions and 4 deletions
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28
src/replay.c
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@ -128,6 +128,26 @@ int replay_write_stage_event(ReplayEvent *evt, SDL_RWops *file) {
return True;
}
uint32_t replay_calc_stageinfo_checksum(ReplayStage *stg) {
uint32_t cs = 0;
cs += stg->stage;
cs += stg->seed;
cs += stg->diff;
cs += stg->points;
cs += stg->plr_char;
cs += stg->plr_shot;
cs += stg->plr_pos_x;
cs += stg->plr_pos_y;
cs += stg->plr_focus;
cs += stg->plr_fire;
cs += stg->plr_power;
cs += stg->plr_lifes;
cs += stg->plr_bombs;
cs += stg->plr_moveflags;
cs += stg->ecount;
return cs;
}
int replay_write_stage(ReplayStage *stg, SDL_RWops *file) {
int i;
@ -146,6 +166,7 @@ int replay_write_stage(ReplayStage *stg, SDL_RWops *file) {
SDL_WriteU8(file, stg->plr_bombs);
SDL_WriteU8(file, stg->plr_moveflags);
SDL_WriteLE16(file, stg->ecount);
SDL_WriteLE32(file, 1 + ~replay_calc_stageinfo_checksum(stg));
for(i = 0; i < stg->ecount; ++i) {
if(!replay_write_stage_event(&stg->events[i], file)) {
@ -261,6 +282,11 @@ int replay_read(Replay *rpy, SDL_RWops *file) {
CHECKPROP(stg->plr_moveflags = SDL_ReadU8(file), u);
CHECKPROP(stg->ecount = SDL_ReadLE16(file), u);
if(replay_calc_stageinfo_checksum(stg) + SDL_ReadLE32(file)) {
warnx("replay_read(): stageinfo is corrupt");
return False;
}
if(!stg->ecount) {
warnx("replay_read(): no events in stage");
return False;
@ -423,7 +449,7 @@ int replay_test(void) {
errx(-1, "Succeeded loading garbage data as a replay... that shouldn't happen");
}
replay_destroy(rpy);
replay_destroy(&rpy);
free(buf);
return 1;
#else

6
src/replay.h
View file

@ -14,7 +14,7 @@
#define REPLAY_ALLOC_INITIAL 256
#define REPLAY_EXTENSION "tsr"
#define REPLAY_STRUCT_VERSION 2
#define REPLAY_STRUCT_VERSION 3
#define REPLAY_USELESS_BYTE 0x69
#ifdef DEBUG
@ -46,11 +46,11 @@ typedef struct ReplayStage {
uint8_t plr_lifes;
uint8_t plr_bombs;
uint8_t plr_moveflags;
// events
ReplayEvent *events;
uint16_t ecount;
// The fields below should not be stored
int capacity;
int playpos;