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opensc-explorer: extend do_asn1() to accept offsets 

Have do_asn1() accept an optional parameter indicating an offset.
If this is given then start ASN.1-decoding the file/record at this offset.
This commit is contained in:
Peter Marschall 2020-05-21 10:50:53 +02:00 committed by Jakub Jelen
parent 45e7039940
commit 4dbfc77eba
2 changed files with 28 additions and 11 deletions
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7
doc/tools/opensc-explorer.1.xml
View File

@ -167,6 +167,7 @@
<command>asn1</command>
<replaceable>file-id</replaceable>
<arg choice="opt"><replaceable>rec-no</replaceable></arg>
<arg choice="opt"><replaceable>offs</replaceable></arg>
</term>
<listitem>
<para>
@ -176,6 +177,12 @@
<replaceable>rec-no</replaceable> is given and the file is
a record-oriented EF, parse and print only the record
indicated by this parameter.
If the optional parameter
<replaceable>offs</replaceable> is given, start parsing
and printing the file or record at the offset indicated
by the value given.
If this parameter is not given, the default offset is
<literal>0</literal>.
</para>
</listitem>
</varlistentry>

32
src/tools/opensc-explorer.c
View File

@ -206,7 +206,7 @@ static struct command cmds[] = {
"apdu", "<data> ...",
"send a custom apdu command" },
{ do_asn1,
"asn1", "[<file-id> [<rec-no>]]",
"asn1", "[<file-id> [<rec-no>] [<offs>]]",
"decode an ASN.1 file or record" },
{ do_sm,
"sm", "{open|close}",
@ -2055,19 +2055,19 @@ static int do_apdu(int argc, char **argv)
fprintf(stderr, "Failure: %s\n", sc_strerror(r));
else
printf("Success!\n");
return 0;
}
static int do_asn1(int argc, char **argv)
{
int r, err = 1;
unsigned int offs = 0;
sc_path_t path;
sc_file_t *file = NULL;
int not_current = 1;
u8 buf[SC_MAX_EXT_APDU_DATA_SIZE];
if (argc > 2)
if (argc > 3)
return usage(do_asn1);
/* select file */
@ -2098,11 +2098,14 @@ static int do_asn1(int argc, char **argv)
if (file->ef_structure == SC_FILE_EF_TRANSPARENT) {
size_t size = (file->size > 0) ? file->size : sizeof(buf);
if (argc > 1) {
fprintf(stderr, "Transparent EFs do not support records\n");
if (argc > 2) {
fprintf(stderr, "Transparent EFs do not have records\n");
goto err;
}
if (argc > 1)
offs = (unsigned int) strtoul(argv[1], NULL, 10);
r = sc_lock(card);
if (r == SC_SUCCESS)
r = sc_read_binary(card, 0, buf, MIN(size, sizeof(buf)), 0);
@ -2114,9 +2117,9 @@ static int do_asn1(int argc, char **argv)
if ((size_t) r != file->size) {
fprintf(stderr, "WARNING: expecting %"SC_FORMAT_LEN_SIZE_T"u, got %d bytes.\n",
file->size, r);
/* some cards return a bogus value for file length. As
* long as the actual length is not higher than the expected
* length, continue */
/* some cards return a bogus value for file length.
* As long as the actual length is not higher
* than the expected length, continue */
if ((size_t) r > file->size)
goto err;
}
@ -2130,6 +2133,9 @@ static int do_asn1(int argc, char **argv)
}
rec = (unsigned int) strtoul(argv[1], NULL, 10);
if (argc > 2)
offs = (unsigned int) strtoul(argv[2], NULL, 10);
if (rec < 1 || rec > file->record_count) {
fprintf(stderr, "Invalid record number %u.\n", rec);
goto err;
@ -2147,10 +2153,14 @@ static int do_asn1(int argc, char **argv)
}
}
/* asn1 dump */
sc_asn1_print_tags(buf, r);
/* if offset does not exceed the length read from file/record, ... */
if (offs <= (unsigned int) r) {
/* ... perform the ASN.1 dump */
sc_asn1_print_tags(buf + offs, (unsigned int) r - offs);
err = 0;
}
err = 0;
err:
if (not_current) {
sc_file_free(file);