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[pki] improve ASN.1 parser

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* Enable search from OIDs expressed as strings and ignore non UNIVERSAL classes
This commit is contained in:
Pete Batard 2017-09-04 14:32:56 +01:00
parent a73e695ba4
commit 94e4c0905b
4 changed files with 119 additions and 28 deletions
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126
src/parser.c
View file

@ -1266,29 +1266,34 @@ char* replace_char(const char* src, const char c, const char* rep)
return res;
}
static void* get_oid_data_from_asn1_internal(const uint8_t* buf, size_t buf_len, const void* oid,
static void* get_data_from_asn1_internal(const uint8_t* buf, size_t buf_len, const void* oid,
size_t oid_len, uint8_t asn1_type, size_t* data_len, BOOL* matched)
{
void* ret;
size_t pos = 0, len, len_len, i;
uint8_t tag;
BOOL is_sequence;
BOOL is_sequence, is_universal_tag;
while (pos < buf_len) {
is_sequence = buf[pos] & 0x20; // Only need to handle the sequence attribute
is_sequence = buf[pos] & 0x20;
is_universal_tag = ((buf[pos] & 0xC0) == 0x00);
tag = buf[pos++] & 0x1F;
if (tag == 0x1F) {
uprintf("get_data_from_asn1: Long form tags are unsupported");
return NULL;
}
// Compute the length
len = 0;
len_len = 1;
if (tag == 0x05) { // ignore "NULL" tag
if ((is_universal_tag) && (tag == 0x05)) { // ignore "NULL" tag
pos++;
} else {
if (buf[pos] & 0x80) {
len_len = buf[pos++] & 0x7F;
// The data we're dealing with is not expected to ever be larger than 64K
if (len_len > 2) {
uprintf("get_oid_data_from_asn1: Length fields larger than 2 bytes are unsupported");
uprintf("get_data_from_asn1: Length fields larger than 2 bytes are unsupported");
return NULL;
}
for (i = 0; i < len_len; i++) {
@ -1300,23 +1305,23 @@ static void* get_oid_data_from_asn1_internal(const uint8_t* buf, size_t buf_len,
}
if (len > buf_len - pos) {
uprintf("get_oid_data_from_asn1: Overflow error (computed length %d is larger than remaining data)", len);
uprintf("get_data_from_asn1: Overflow error (computed length %d is larger than remaining data)", len);
return NULL;
}
}
if (len != 0) {
if (is_sequence) {
ret = get_oid_data_from_asn1_internal(&buf[pos], len, oid, oid_len, asn1_type, data_len, matched);
ret = get_data_from_asn1_internal(&buf[pos], len, oid, oid_len, asn1_type, data_len, matched);
if (ret != NULL)
return ret;
} else {
} else if (is_universal_tag) { // Only process tags that belong to the UNIVERSAL class
// NB: 0x06 = "OID" tag
if ((!*matched) && (tag == 0x06) && (len == oid_len) && (memcmp(&buf[pos], oid, oid_len) == 0)) {
*matched = TRUE;
} else if ((*matched) && (tag == asn1_type)) {
*data_len = len;
return (void*) &buf[pos];
return (void*)&buf[pos];
}
}
pos += len;
@ -1326,15 +1331,104 @@ static void* get_oid_data_from_asn1_internal(const uint8_t* buf, size_t buf_len,
return NULL;
}
// Helper functions to convert an OID string to an OID byte array
// Taken from from openpgp-oid.c
static size_t make_flagged_int(unsigned long value, uint8_t *buf, size_t buflen)
{
BOOL more = FALSE;
int shift;
for (shift = 28; shift > 0; shift -= 7) {
if (more || value >= ((unsigned long)1 << shift)) {
buf[buflen++] = (uint8_t) (0x80 | (value >> shift));
value -= (value >> shift) << shift;
more = TRUE;
}
}
buf[buflen++] = (uint8_t) value;
return buflen;
}
// Convert OID string 'oid_str' to an OID byte array of size 'ret_len'
// The returned array must be freed by the caller.
static uint8_t* oid_from_str(const char* oid_str, size_t* ret_len)
{
uint8_t* oid = NULL;
unsigned long val1 = 0, val;
const char *endp;
int arcno = 0;
size_t oid_len = 0;
if ((oid_str == NULL) || (oid_str[0] == 0))
return NULL;
// We can safely assume that the encoded OID is shorter than the string.
oid = malloc(1 + strlen(oid_str) + 2);
if (oid == NULL)
return NULL;
do {
arcno++;
val = strtoul(oid_str, (char**)&endp, 10);
if (!isdigit(*oid_str) || !(*endp == '.' || !*endp))
goto err;
if (*endp == '.')
oid_str = endp + 1;
if (arcno == 1) {
if (val > 2)
break; // Not allowed, error caught below.
val1 = val;
} else if (arcno == 2) {
// Need to combine the first two arcs in one byte.
if (val1 < 2) {
if (val > 39)
goto err;
oid[oid_len++] = (uint8_t)(val1 * 40 + val);
} else {
val += 80;
oid_len = make_flagged_int(val, oid, oid_len);
}
} else {
oid_len = make_flagged_int(val, oid, oid_len);
}
} while (*endp == '.');
// It is not possible to encode only the first arc.
if (arcno == 1 || oid_len < 2 || oid_len > 254)
goto err;
*ret_len = oid_len;
return oid;
err:
free(oid);
return NULL;
}
/*
* Parse an ASN.1 binary buffer and return a pointer to the first instance of OID data of type 'asn1_type',
* matching the binary OID 'oid' (of size 'oid_len'). If successful, the length or the returned data is
* placed in 'data_len'.
* If 'oid' is NULL, the first data element of type 'asn1_type' is returned.
* matching the OID 'oid_str' (expressed as an OID string). If successful, the length or the returned data
* is placed in 'data_len'. Note: Only the UNIVERSAL class is supported for 'asn1_type' (other classes are
* ignored). If 'oid_str' is NULL or empty, the first data element of type 'asn1_type' is returned.
*/
void* get_oid_data_from_asn1(const uint8_t* buf, size_t buf_len, const uint8_t* oid, size_t oid_len,
uint8_t asn1_type, size_t* data_len)
void* get_data_from_asn1(const uint8_t* buf, size_t buf_len, const char* oid_str, uint8_t asn1_type, size_t* data_len)
{
BOOL matched = (oid == NULL);
return get_oid_data_from_asn1_internal(buf, buf_len, oid, oid_len, asn1_type, data_len, &matched);
void* ret;
uint8_t* oid = NULL;
size_t oid_len = 0;
BOOL matched = ((oid_str == NULL) || (oid_str[0] == 0));
if (!matched) {
// We have an OID string to convert
oid = oid_from_str(oid_str, &oid_len);
if (oid == NULL) {
uprintf("get_oid_data_from_asn1: Could not convert OID string '%s'", oid_str);
return NULL;
}
}
ret = get_data_from_asn1_internal(buf, buf_len, oid, oid_len, asn1_type, data_len, &matched);
free(oid);
return ret;
}

8
src/pki.c
View file

@ -239,8 +239,6 @@ out:
// The timestamping authorities we use are RFC 3161 compliant
static uint64_t GetRFC3161TimeStamp(PCMSG_SIGNER_INFO pSignerInfo)
{
// Binary representation of szOID_TIMESTAMP_TOKEN or "1.2.840.113549.1.9.16.1.4"
const uint8_t OID_RFC3161_timeStamp[] = { 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x09, 0x10, 0x01, 0x04 };
BOOL r, found = FALSE;
DWORD n, dwSize;
PCRYPT_CONTENT_INFO pCounterSignerInfo = NULL;
@ -273,12 +271,12 @@ static uint64_t GetRFC3161TimeStamp(PCMSG_SIGNER_INFO pSignerInfo)
}
// Get the RFC 3161 timestamp message
timestamp_token = get_oid_data_from_asn1(pCounterSignerInfo->Content.pbData,
pCounterSignerInfo->Content.cbData, OID_RFC3161_timeStamp, sizeof(OID_RFC3161_timeStamp),
timestamp_token = get_data_from_asn1(pCounterSignerInfo->Content.pbData,
pCounterSignerInfo->Content.cbData, szOID_TIMESTAMP_TOKEN,
// 0x04 = "Octet String" ASN.1 tag
0x04, &timestamp_token_size);
if (timestamp_token) {
timestamp_str = get_oid_data_from_asn1(timestamp_token, timestamp_token_size, NULL, 0,
timestamp_str = get_data_from_asn1(timestamp_token, timestamp_token_size, NULL,
// 0x18 = "Generalized Time" ASN.1 tag
0x18, &timestamp_str_size);
if (timestamp_str) {

3
src/rufus.h
View file

@ -478,8 +478,7 @@ extern char* insert_section_data(const char* filename, const char* section, cons
extern char* replace_in_token_data(const char* filename, const char* token, const char* src, const char* rep, BOOL dos2unix);
extern char* replace_char(const char* src, const char c, const char* rep);
extern void parse_update(char* buf, size_t len);
extern void* get_oid_data_from_asn1(const uint8_t* buf, size_t buf_len, const uint8_t* oid, size_t oid_len,
uint8_t asn1_type, size_t* data_len);
extern void* get_data_from_asn1(const uint8_t* buf, size_t buf_len, const char* oid_str, uint8_t asn1_type, size_t* data_len);
extern uint8_t WimExtractCheck(void);
extern BOOL WimExtractFile(const char* wim_image, int index, const char* src, const char* dst);
extern BOOL WimExtractFile_API(const char* image, int index, const char* src, const char* dst);

10
src/rufus.rc
View file

@ -33,7 +33,7 @@ LANGUAGE LANG_NEUTRAL, SUBLANG_NEUTRAL
IDD_DIALOG DIALOGEX 12, 12, 242, 376
STYLE DS_SETFONT | DS_MODALFRAME | DS_CENTER | WS_MINIMIZEBOX | WS_POPUP | WS_CAPTION | WS_SYSMENU
EXSTYLE WS_EX_ACCEPTFILES
CAPTION "Rufus 2.17.1190"
CAPTION "Rufus 2.17.1191"
FONT 8, "Segoe UI Symbol", 400, 0, 0x0
BEGIN
LTEXT "Device",IDS_DEVICE_TXT,9,6,200,8
@ -366,8 +366,8 @@ END
//
VS_VERSION_INFO VERSIONINFO
FILEVERSION 2,17,1190,0
PRODUCTVERSION 2,17,1190,0
FILEVERSION 2,17,1191,0
PRODUCTVERSION 2,17,1191,0
FILEFLAGSMASK 0x3fL
#ifdef _DEBUG
FILEFLAGS 0x1L
@ -384,13 +384,13 @@ BEGIN
BEGIN
VALUE "CompanyName", "Akeo Consulting (http://akeo.ie)"
VALUE "FileDescription", "Rufus"
VALUE "FileVersion", "2.17.1190"
VALUE "FileVersion", "2.17.1191"
VALUE "InternalName", "Rufus"
VALUE "LegalCopyright", "© 2011-2017 Pete Batard (GPL v3)"
VALUE "LegalTrademarks", "http://www.gnu.org/copyleft/gpl.html"
VALUE "OriginalFilename", "rufus.exe"
VALUE "ProductName", "Rufus"
VALUE "ProductVersion", "2.17.1190"
VALUE "ProductVersion", "2.17.1191"
END
END
BLOCK "VarFileInfo"