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[src/trunk]: src/games/adventure Oops, I forgot to actually implement the che...
details: https://anonhg.NetBSD.org/src/rev/6e2ab47a38e4
branches: trunk
changeset: 772564:6e2ab47a38e4
user: dholland <dholland%NetBSD.org@localhost>
date: Sun Jan 08 18:16:00 2012 +0000
description:
Oops, I forgot to actually implement the checksumming code for the new
savefile format, so any savefiles generated yesterday can be tampered
with. Oh well. While here, tidy up the crc code.
diffstat:
games/adventure/crc.c | 53 ++++++++++++++++++++++++++++-------------------
games/adventure/extern.h | 12 ++++++++--
games/adventure/save.c | 38 ++++++++++++++++++++++-----------
3 files changed, 65 insertions(+), 38 deletions(-)
diffs (260 lines):
diff -r a003aa40a344 -r 6e2ab47a38e4 games/adventure/crc.c
--- a/games/adventure/crc.c Sun Jan 08 18:06:00 2012 +0000
+++ b/games/adventure/crc.c Sun Jan 08 18:16:00 2012 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: crc.c,v 1.12 2012/01/07 18:08:35 dholland Exp $ */
+/* $NetBSD: crc.c,v 1.13 2012/01/08 18:16:00 dholland Exp $ */
/*-
* Copyright (c) 1993
@@ -38,13 +38,13 @@
static char sccsid[] = "@(#)crc.c 8.1 (Berkeley) 5/31/93";
static char ORIGINAL_sccsid[] = "@(#)crc.c 5.2 (Berkeley) 4/4/91";
#else
-__RCSID("$NetBSD: crc.c,v 1.12 2012/01/07 18:08:35 dholland Exp $");
+__RCSID("$NetBSD: crc.c,v 1.13 2012/01/08 18:16:00 dholland Exp $");
#endif
#endif /* not lint */
#include "extern.h"
-static const unsigned long crctab[] = {
+static const uint32_t crctab[256] = {
0x7fffffff,
0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e,
@@ -98,6 +98,7 @@
0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02,
0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
};
+
/*
* crc --
* Compute a POSIX.2 checksum. This routine modified by Jim Gillogly
@@ -106,31 +107,39 @@
* it.
*/
-static unsigned long crcval;
-static unsigned int step;
-
void
-crc_start(void)
+crc_start(struct crcstate *c)
{
- crcval = step = 0;
+ c->crcval = 0;
+ c->step = 0;
}
-/* Process nr bytes at a time; ptr points to them */
-unsigned long
-crc(const char *ptr, int nr)
+/*
+ * Process NUM bytes pointed to by DATA
+ */
+void
+crc_add(struct crcstate *c, const void *data, size_t num)
{
- int i;
- const char *p;
+ const unsigned char *udata;
+ size_t pos;
+ unsigned x;
- while (nr > 0)
- for (p = ptr; nr--; ++p) {
- i = (crcval >> 24 ^ (unsigned char)*p) & 0xff;
- if (i == 0) {
- i = step++;
- if (step >= sizeof(crctab) / sizeof(crctab[0]))
- step = 0;
+ udata = data;
+ pos = 0;
+ while (pos < num) {
+ x = (c->crcval >> 24 ^ udata[pos++]) & 0xff;
+ if (x == 0) {
+ x = c->step++;
+ if (c->step >= __arraycount(crctab)) {
+ c->step = 0;
}
- crcval = (crcval << 8) ^ crctab[i];
}
- return crcval & 0xffffffff; /* Mask to 32 bits. */
+ c->crcval = (c->crcval << 8) ^ crctab[x];
+ }
}
+
+uint32_t
+crc_get(struct crcstate *c)
+{
+ return c->crcval;
+}
diff -r a003aa40a344 -r 6e2ab47a38e4 games/adventure/extern.h
--- a/games/adventure/extern.h Sun Jan 08 18:06:00 2012 +0000
+++ b/games/adventure/extern.h Sun Jan 08 18:16:00 2012 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: extern.h,v 1.14 2009/10/21 01:07:44 snj Exp $ */
+/* $NetBSD: extern.h,v 1.15 2012/01/08 18:16:00 dholland Exp $ */
/*
* Copyright (c) 1997 Christos Zoulas. All rights reserved.
@@ -27,8 +27,14 @@
#include <string.h>
/* crc.c */
-void crc_start(void);
-unsigned long crc(const char *, int);
+struct crcstate {
+ uint32_t crcval;
+ unsigned step;
+};
+
+void crc_start(struct crcstate *);
+void crc_add(struct crcstate *, const void *, size_t);
+uint32_t crc_get(struct crcstate *);
/* done.c */
int score(void);
diff -r a003aa40a344 -r 6e2ab47a38e4 games/adventure/save.c
--- a/games/adventure/save.c Sun Jan 08 18:06:00 2012 +0000
+++ b/games/adventure/save.c Sun Jan 08 18:16:00 2012 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: save.c,v 1.12 2012/01/07 22:23:16 dholland Exp $ */
+/* $NetBSD: save.c,v 1.13 2012/01/08 18:16:00 dholland Exp $ */
/*-
* Copyright (c) 1991, 1993
@@ -39,7 +39,7 @@
#if 0
static char sccsid[] = "@(#)save.c 8.1 (Berkeley) 5/31/93";
#else
-__RCSID("$NetBSD: save.c,v 1.12 2012/01/07 22:23:16 dholland Exp $");
+__RCSID("$NetBSD: save.c,v 1.13 2012/01/08 18:16:00 dholland Exp $");
#endif
#endif /* not lint */
@@ -60,13 +60,14 @@
bool warned;
unsigned bintextpos;
uint32_t key;
- uint32_t sum;
+ struct crcstate crc;
unsigned char pad[8];
unsigned padpos;
};
#define BINTEXT_WIDTH 60
-#define FORMAT_VERSION 1
+#define FORMAT_VERSION 2
+#define FORMAT_VERSION_NOSUM 1
static const char header[] = "Adventure save file\n";
////////////////////////////////////////////////////////////
@@ -133,7 +134,7 @@
sf->warned = false;
sf->bintextpos = 0;
sf->key = 0;
- sf->sum = 0;
+ crc_start(&sf->crc);
memset(sf->pad, 0, sizeof(sf->pad));
sf->padpos = 0;
return sf;
@@ -362,7 +363,7 @@
savefile_key(struct savefile *sf, uint32_t key)
{
sf->key = 0;
- sf->sum = 0;
+ crc_start(&sf->crc);
hash(&sf->key, sizeof(sf->key), sf->pad, sizeof(sf->pad));
sf->padpos = 0;
}
@@ -412,6 +413,7 @@
}
pos += amt;
}
+ crc_add(&sf->crc, data, len);
return 0;
}
@@ -443,6 +445,7 @@
}
pos += amt;
}
+ crc_add(&sf->crc, data, len);
return 0;
}
@@ -528,6 +531,7 @@
char *s;
long sum, cksum = 0;
int i;
+ struct crcstate crc;
if ((in = fopen(infile, "rb")) == NULL) {
fprintf(stderr,
@@ -544,9 +548,10 @@
}
fclose(in);
- crc_start(); /* See if she cheated */
+ crc_start(&crc); /* See if she cheated */
for (p = compat_savearray; p->address != NULL; p++)
- cksum = crc(p->address, p->width);
+ crc_add(&crc, p->address, p->width);
+ cksum = crc_get(&crc);
if (sum != cksum) /* Tsk tsk */
return 2; /* Altered the file */
/* We successfully restored, so this really was a save file */
@@ -661,7 +666,7 @@
uint32_t key, writeable_key;
uint32_t version;
unsigned i, j, n;
- uint32_t val;
+ uint32_t val, sum;
sf = savefile_open(outfile, true);
if (sf == NULL) {
@@ -732,8 +737,8 @@
}
#endif
- sf->sum = htonl(sf->sum);
- if (savefile_binwrite(sf, &sf->sum, sizeof(&sf->sum))) {
+ sum = htonl(crc_get(&sf->crc));
+ if (savefile_binwrite(sf, &sum, sizeof(&sum))) {
savefile_close(sf);
return 1;
}
@@ -753,6 +758,7 @@
uint32_t version, key, sum;
unsigned i, j, n;
uint32_t val;
+ bool skipsum = false;
sf = savefile_open(infile, false);
if (sf == NULL) {
@@ -777,7 +783,13 @@
return 1;
}
version = ntohl(version);
- if (version != FORMAT_VERSION) {
+ switch (version) {
+ case FORMAT_VERSION:
+ break;
+ case FORMAT_VERSION_NOSUM:
+ skipsum = true;
+ break;
+ default:
savefile_close(sf);
fprintf(stderr,
"Oh dear, that file must be from the future. I don't know"
@@ -840,7 +852,7 @@
}
sum = ntohl(sum);
/* See if she cheated */
- if (sum != sf->sum) {
+ if (!skipsum && sum != crc_get(&sf->crc)) {
/* Tsk tsk, altered the file */
savefile_close(sf);
return 2;
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