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http: use OCSP_check_validity to check OCSP validity
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@aberaud
Adrien Béraud authored and aberaud committed Mar 17, 2024
1 parent fcffcee commit 7ca39b4
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Showing 4 changed files with 40 additions and 201 deletions.
91 changes: 0 additions & 91 deletions src/compat/os_cert.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -17,7 +17,6 @@
*/

#include "os_cert.h"

#include "logger.h"

#ifdef _WIN32
Expand All @@ -32,96 +31,6 @@
#include <Security/Security.h>
#endif /*TARGET_OS_OSX*/

#if EMBEDDED_ASN1_TIME_PARSE
#undef X509_NAME
#undef OCSP_REQUEST
#undef OCSP_RESPONSE
#define GENTIME_LENGTH 15
#define UTCTIME_LENGTH 13
#define ATOI2(ar) ((ar) += 2, ((ar)[-2] - '0') * 10 + ((ar)[-1] - '0'))
extern "C" {
// Taken from libressl/src/crypto/asn1/a_time_tm.c
int
ASN1_time_parse(const char* bytes, size_t len, struct tm* tm, int mode)
{
size_t i;
int type = 0;
struct tm ltm;
struct tm* lt;
const char* p;

if (bytes == NULL)
return (-1);

/* Constrain to valid lengths. */
if (len != UTCTIME_LENGTH && len != GENTIME_LENGTH)
return (-1);

lt = tm;
if (lt == NULL) {
memset(&ltm, 0, sizeof(ltm));
lt = &ltm;
}

/* Timezone is required and must be GMT (Zulu). */
if (bytes[len - 1] != 'Z')
return (-1);

/* Make sure everything else is digits. */
for (i = 0; i < len - 1; i++) {
if (isdigit((unsigned char) bytes[i]))
continue;
return (-1);
}

/*
* Validate and convert the time
*/
p = bytes;
switch (len) {
case GENTIME_LENGTH:
if (mode == V_ASN1_UTCTIME)
return (-1);
lt->tm_year = (ATOI2(p) * 100) - 1900; /* cc */
type = V_ASN1_GENERALIZEDTIME;
/* FALLTHROUGH */
case UTCTIME_LENGTH:
if (type == 0) {
if (mode == V_ASN1_GENERALIZEDTIME)
return (-1);
type = V_ASN1_UTCTIME;
}
lt->tm_year += ATOI2(p); /* yy */
if (type == V_ASN1_UTCTIME) {
if (lt->tm_year < 50)
lt->tm_year += 100;
}
lt->tm_mon = ATOI2(p) - 1; /* mm */
if (lt->tm_mon < 0 || lt->tm_mon > 11)
return (-1);
lt->tm_mday = ATOI2(p); /* dd */
if (lt->tm_mday < 1 || lt->tm_mday > 31)
return (-1);
lt->tm_hour = ATOI2(p); /* HH */
if (lt->tm_hour < 0 || lt->tm_hour > 23)
return (-1);
lt->tm_min = ATOI2(p); /* MM */
if (lt->tm_min < 0 || lt->tm_min > 59)
return (-1);
lt->tm_sec = ATOI2(p); /* SS */
/* Leap second 60 is not accepted. Reconsider later? */
if (lt->tm_sec < 0 || lt->tm_sec > 59)
return (-1);
break;
default:
return (-1);
}

return type;
}
}
#endif /* EMBEDDED_ASN1_TIME_PARSE */

namespace dht {
namespace http {

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30 changes: 0 additions & 30 deletions src/compat/os_cert.h
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Original file line number Diff line number Diff line change
Expand Up @@ -24,36 +24,6 @@

#include <openssl/x509.h>

#if (defined(LIBRESSL_VERSION_NUMBER) && (LIBRESSL_VERSION_NUMBER > 0x20501000L))
#define EMBEDDED_ASN1_TIME_PARSE 0
#else
#define EMBEDDED_ASN1_TIME_PARSE 1
#endif

#if EMBEDDED_ASN1_TIME_PARSE
#define V_ASN1_UTCTIME 23
#define V_ASN1_GENERALIZEDTIME 24

extern "C" {
/*
* Parse an RFC 5280 format ASN.1 time string.
*
* mode must be:
* 0 if we expect to parse a time as specified in RFC 5280 for an X509 object.
* V_ASN1_UTCTIME if we wish to parse an RFC5280 format UTC time.
* V_ASN1_GENERALIZEDTIME if we wish to parse an RFC5280 format Generalized time.
*
* Returns:
* -1 if the string was invalid.
* V_ASN1_UTCTIME if the string validated as a UTC time string.
* V_ASN1_GENERALIZEDTIME if the string validated as a Generalized time string.
*
* Fills in *tm with the corresponding time if tm is non NULL.
*/
int ASN1_time_parse(const char* bytes, size_t len, struct tm* tm, int mode);
}
#endif

namespace dht {
namespace http {

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1 change: 0 additions & 1 deletion src/dht_proxy_client.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -26,7 +26,6 @@
#include <http_parser.h>
#include <deque>


namespace dht {

struct DhtProxyClient::InfoState {
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119 changes: 40 additions & 79 deletions src/http.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -225,20 +225,25 @@ Connection::is_ssl() const
return ssl_ctx_ ? true : false;
}

static time_t
parse_ocsp_time(ASN1_GENERALIZEDTIME* gt)
{
struct tm tm;
time_t rv = -1;
std::string asn1ToString(ASN1_GENERALIZEDTIME* time) {
if (!time) {
return "(null)";
}
BIO* memBio = BIO_new(BIO_s_mem());
if (!memBio) {
throw std::runtime_error("Failed to create BIO");
}

if (ASN1_GENERALIZEDTIME_print(memBio, time) <= 0) {
BIO_free(memBio);
throw std::runtime_error("Failed to print ASN1_GENERALIZEDTIME");
}

if (gt == nullptr)
return -1;
// RFC 6960 specifies that all times in OCSP must be GENERALIZEDTIME
if (ASN1_time_parse((const char*)gt->data, gt->length, &tm, V_ASN1_GENERALIZEDTIME) == -1)
return -1;
if ((rv = timegm(&tm)) == -1)
return -1;
return rv;
char* bioData;
long bioLength = BIO_get_mem_data(memBio, &bioData);
std::string result(bioData, bioLength);
BIO_free(memBio);
return result;
}

static inline X509*
Expand Down Expand Up @@ -342,136 +347,92 @@ ocspRequestFromCert(STACK_OF(X509)* fullchain, const std::shared_ptr<Logger>& lo
bool
ocspValidateResponse(const OscpRequestInfo& info, STACK_OF(X509)* fullchain, const std::string& response, X509_STORE *store, const std::shared_ptr<Logger>& logger)
{
ASN1_GENERALIZEDTIME *revtime = nullptr, *thisupd = nullptr, *nextupd = nullptr;
const uint8_t* p = (const uint8_t*)response.data();
int status, cert_status=0, crl_reason=0;
time_t now, rev_t = -1, this_t, next_t;

X509* cert = cert_from_chain(fullchain);
if (cert == nullptr) {
if (logger)
logger->e("No certificate found");
logger->error("ocsp: no certificate found");
return false;
}
X509* issuer = issuer_from_chain(fullchain);
if (issuer == nullptr) {
if (logger)
logger->e("Unable to find issuer for cert");
logger->error("ocsp: unable to find issuer for cert");
return false;
}

OCSP_CERTID *cidr;
if ((cidr = OCSP_cert_to_id(nullptr, cert, issuer)) == nullptr) {
if (logger)
logger->e("Unable to get issuer cert/CID");
logger->error("ocsp: unable to get issuer cert/CID");
return false;
}
std::unique_ptr<OCSP_CERTID, decltype(&OCSP_CERTID_free)> cid(cidr, &OCSP_CERTID_free);

const uint8_t* resp_data = (const uint8_t*)response.data();
OCSP_RESPONSE *r;
if ((r = d2i_OCSP_RESPONSE(nullptr, &p, response.size())) == nullptr) {
if ((r = d2i_OCSP_RESPONSE(nullptr, &resp_data, response.size())) == nullptr) {
if (logger)
logger->e("OCSP response unserializable");
logger->error("OCSP response unserializable");
return false;
}
std::unique_ptr<OCSP_RESPONSE, decltype(&OCSP_RESPONSE_free)> resp(r, &OCSP_RESPONSE_free);

OCSP_BASICRESP *brespr;
if ((brespr = OCSP_response_get1_basic(resp.get())) == nullptr) {
if (logger)
logger->e("Failed to load OCSP response");
logger->error("Failed to load OCSP response");
return false;
}
std::unique_ptr<OCSP_BASICRESP, decltype(&OCSP_BASICRESP_free)> bresp(brespr, &OCSP_BASICRESP_free);

if (OCSP_basic_verify(bresp.get(), fullchain, store, OCSP_TRUSTOTHER) != 1) {
if (logger)
logger->w("OCSP verify failed");
logger->warn("OCSP verify failed");
return false;
}
printf("OCSP response signature validated\n");

status = OCSP_response_status(resp.get());
int status = OCSP_response_status(resp.get());
if (status != OCSP_RESPONSE_STATUS_SUCCESSFUL) {
if (logger)
logger->w("OCSP Failure: code %d (%s)", status, OCSP_response_status_str(status));
logger->warn("OCSP Failure: code {:d} ({:s})", status, OCSP_response_status_str(status));
return false;
}

// Check the nonce if we sent one
if (OCSP_check_nonce(info.req.get(), bresp.get()) <= 0) {
if (logger)
logger->w("No OCSP nonce, or mismatch");
logger->warn("No OCSP nonce, or mismatch");
return false;
}

ASN1_GENERALIZEDTIME *revtime = nullptr, *thisupd = nullptr, *nextupd = nullptr;
int cert_status=0, crl_reason=0;
if (OCSP_resp_find_status(bresp.get(), cid.get(), &cert_status, &crl_reason,
&revtime, &thisupd, &nextupd) != 1) {
if (logger)
logger->w("OCSP verify failed: no result for cert");
logger->warn("OCSP verify failed: no result for cert");
return false;
}

if (revtime && (rev_t = parse_ocsp_time(revtime)) == -1) {
if (logger)
logger->w("Unable to parse revocation time in OCSP reply");
return false;
}
// Belt and suspenders, Treat it as revoked if there is either
// a revocation time, or status revoked.
if (rev_t != -1 || cert_status == V_OCSP_CERTSTATUS_REVOKED) {
if (logger)
logger->w("Invalid OCSP reply: certificate is revoked");
if (rev_t != -1) {
if (logger)
logger->w("Certificate revoked at: %s", ctime(&rev_t));
if (revtime || cert_status == V_OCSP_CERTSTATUS_REVOKED) {
if (logger) {
logger->warn("OCSP verify failed: certificate revoked since {}", asn1ToString(revtime));
}
return false;
}
if ((this_t = parse_ocsp_time(thisupd)) == -1) {
if (logger)
logger->w("unable to parse this update time in OCSP reply");
return false;
}
if ((next_t = parse_ocsp_time(nextupd)) == -1) {
if (logger)
logger->w("unable to parse next update time in OCSP reply");
return false;
}

// Don't allow this update to precede next update
if (this_t >= next_t) {
if (logger)
logger->w("Invalid OCSP reply: this update >= next update");
return false;
}

now = time(nullptr);
// Check that this update is not more than JITTER seconds in the future.
if (this_t > now + JITTER_SEC) {
if (logger)
logger->e("Invalid OCSP reply: this update is in the future (%s)", ctime(&this_t));
return false;
}

// Check that this update is not more than MAXSEC in the past.
if (this_t < now - MAXAGE_SEC) {
if (logger)
logger->e("Invalid OCSP reply: this update is too old (%s)", ctime(&this_t));
return false;
}

// Check that next update is still valid
if (next_t < now - JITTER_SEC) {
if (OCSP_check_validity(thisupd, nextupd, 1, -1) == 0) {
if (logger)
logger->w("Invalid OCSP reply: reply has expired (%s)", ctime(&next_t));
logger->warn("OCSP reply is expired or not yet valid");
return false;
}

if (logger) {
logger->d("OCSP response validated");
logger->d(" This Update: %s", ctime(&this_t));
logger->d(" Next Update: %s", ctime(&next_t));
logger->debug("OCSP response validated");
logger->debug(" This Update: {}", asn1ToString(thisupd));
logger->debug(" Next Update: {}", asn1ToString(nextupd));
}
return true;
}
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