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snappy-fox
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unframed and byte substitution

This commit is contained in:
Davide Berardi 2024-02-19 11:08:01 +01:00
parent 18dda8559a
commit b292926d43
1 changed files with 39 additions and 15 deletions
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54
snappy-fox.c
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@ -45,6 +45,10 @@
/* Flags */ /* Flags */
/* Unframed file stream, by default assume framed file */ /* Unframed file stream, by default assume framed file */
static uint32_t unframed_stream = 0; static uint32_t unframed_stream = 0;
/* Ignore offset errors, by default consider them as fatal errors*/
static uint32_t ignore_offset_errors = 0;
/* Byte to substitute offset corrupted values with */
static uint8_t offset_dummy_byte = 0xff;
/* Logarithm base two of the number */ /* Logarithm base two of the number */
static uint32_t log2_32(uint32_t n) { static uint32_t log2_32(uint32_t n) {
@ -137,18 +141,28 @@ static int32_t parse_literal(uint8_t *cdata, uint32_t cidx, uint32_t clength,
static int offsetread(uint8_t *data, uint32_t *idx, uint32_t length, static int offsetread(uint8_t *data, uint32_t *idx, uint32_t length,
uint32_t clen, uint32_t coff) { uint32_t clen, uint32_t coff) {
int ret = 0;
uint32_t i; uint32_t i;
prdebug("Copying %d bytes offset %d (pos: %d)\n", prdebug("Copying %d bytes offset %d (pos: %d)\n",
clen, coff, *idx); clen, coff, *idx);
/* Ignore invalid offset */ /* Ignore invalid offset */
if (*idx < coff || coff == 0) if (*idx < coff || coff == 0)
return -1; ret = -1;
if (*idx + clen > length) if (*idx + clen > length)
return -1; ret = -1;
if (coff >= clen) { /* Check if we can ignore errors */
if (ret != 0 && !ignore_offset_errors) {
prerror("Offset error\n");
} else if (ret != 0 && ignore_offset_errors) {
prinfo("Ignoring offset errors\n");
for (i = 0; i < clen; ++i)
data[*idx+i] = offset_dummy_byte;
*idx = *idx + clen;
ret = 0;
} else if (coff >= clen) {
memcpy(&data[*idx], &data[*idx - coff], clen); memcpy(&data[*idx], &data[*idx - coff], clen);
*idx += clen; *idx += clen;
} else { } else {
@ -159,7 +173,7 @@ static int offsetread(uint8_t *data, uint32_t *idx, uint32_t length,
memcpy(&data[*idx], &data[*idx - coff], clen % coff); memcpy(&data[*idx], &data[*idx - coff], clen % coff);
*idx += clen % coff; *idx += clen % coff;
} }
return 0; return ret;
} }
@ -273,6 +287,7 @@ static FILE *open_read_file(const char *file) {
FILE *in = stdin; FILE *in = stdin;
if (strcmp(file, "-") != 0) if (strcmp(file, "-") != 0)
in = fopen(file, "rb"); in = fopen(file, "rb");
prdebug("Opening IN file: %s\n", file);
return in; return in;
} }
@ -280,6 +295,7 @@ static FILE *open_write_file(const char *file) {
FILE *out = stdout; FILE *out = stdout;
if (strcmp(file, "-") != 0) if (strcmp(file, "-") != 0)
out = fopen(file, "wb"); out = fopen(file, "wb");
prdebug("Opening OUT file: %s\n", file);
return out; return out;
} }
@ -503,9 +519,10 @@ static void usage(const char *progname) {
progname); progname);
fprintf(stderr, " files can be specified as - for stdin or stdout\n"); fprintf(stderr, " files can be specified as - for stdin or stdout\n");
fprintf(stderr, " Options:\n"); fprintf(stderr, " Options:\n");
fprintf(stderr, " -u --unframed Assume Unframed stream in input file\n"); fprintf(stderr, " -E --ignore_offset_errors [substitution byte] Ignore any offset errors that occurs\n");
fprintf(stderr, " -h --help This Help\n"); fprintf(stderr, " -u --unframed Assume Unframed stream in input file\n");
fprintf(stderr, " -v --version Print Version and exit\n"); fprintf(stderr, " -h --help This Help\n");
fprintf(stderr, " -v --version Print Version and exit\n");
} }
int main(int argc, char **argv) { int main(int argc, char **argv) {
@ -515,15 +532,22 @@ int main(int argc, char **argv) {
int option_idx = 0; int option_idx = 0;
static struct option flags[] = { static struct option flags[] = {
{"unframed", no_argument, 0, 'u'}, {"ignore_offset_errors", optional_argument, 0, 'E'},
{"version", no_argument, 0, 'v'}, {"unframed", no_argument, 0, 'u'},
{"help", no_argument, 0, 'h'}, {"version", no_argument, 0, 'v'},
{0, 0, 0, 0} {"help", no_argument, 0, 'h'},
{0, 0, 0, 0}
}; };
while (c != -1) { while (c != -1) {
c = getopt_long(argc, argv, "hv", flags, &option_idx); c = getopt_long(argc, argv, "E?uhv", flags, &option_idx);
switch (c) { switch (c) {
case 'E':
ignore_offset_errors = 1;
/* Set the dummy byte to the passed value */
if (optarg != NULL)
offset_dummy_byte = (strtol(optarg, NULL, 0) & 0xff);
break;
case 'u': case 'u':
unframed_stream = 1; unframed_stream = 1;
break; break;
@ -543,7 +567,7 @@ int main(int argc, char **argv) {
prdebug("Starting snappy-fox\n"); prdebug("Starting snappy-fox\n");
if (argc - option_idx < 2) { if (argc - optind < 2) {
usage(argv[0]); usage(argv[0]);
return 1; return 1;
} }
@ -551,14 +575,14 @@ int main(int argc, char **argv) {
#ifdef __AFL_LOOP #ifdef __AFL_LOOP
while (__AFL_LOOP(1000)) { while (__AFL_LOOP(1000)) {
#endif #endif
in = open_read_file(argv[option_idx]); in = open_read_file(argv[optind]);
if (in == NULL) { if (in == NULL) {
perror("fopen read"); perror("fopen read");
ret = 1; ret = 1;
goto exit_point; goto exit_point;
} }
out = open_write_file(argv[option_idx+1]); out = open_write_file(argv[optind + 1]);
if (out == NULL) { if (out == NULL) {
perror("fopen write"); perror("fopen write");
ret = 1; ret = 1;