MODSIGN: Fix 32-bit overflow in X.509 certificate validity date checking
The current choice of lifetime for the autogenerated X.509 of 100 years,
putting the validTo date in 2112, causes problems on 32-bit systems where a
32-bit time_t wraps in 2106. 64-bit x86_64 systems seem to be unaffected.
This can result in something like:
Loading module verification certificates
X.509: Cert 6e03943da0f3b015ba6ed7f5e0cac4fe48680994 has expired
MODSIGN: Problem loading in-kernel X.509 certificate (-127)
Or:
X.509: Cert 6e03943da0f3b015ba6ed7f5e0cac4fe48680994 is not yet valid
MODSIGN: Problem loading in-kernel X.509 certificate (-129)
Instead of turning the dates into time_t values and comparing, turn the system
clock and the ASN.1 dates into tm structs and compare those piecemeal instead.
Reported-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Josh Boyer <jwboyer@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c
index 8fcac94..db07e8c 100644
--- a/crypto/asymmetric_keys/x509_cert_parser.c
+++ b/crypto/asymmetric_keys/x509_cert_parser.c
@@ -434,11 +434,10 @@
/*
* Record a certificate time.
*/
-static int x509_note_time(time_t *_time, size_t hdrlen,
+static int x509_note_time(struct tm *tm, size_t hdrlen,
unsigned char tag,
const unsigned char *value, size_t vlen)
{
- unsigned YY, MM, DD, hh, mm, ss;
const unsigned char *p = value;
#define dec2bin(X) ((X) - '0')
@@ -448,30 +447,30 @@
/* UTCTime: YYMMDDHHMMSSZ */
if (vlen != 13)
goto unsupported_time;
- YY = DD2bin(p);
- if (YY > 50)
- YY += 1900;
+ tm->tm_year = DD2bin(p);
+ if (tm->tm_year >= 50)
+ tm->tm_year += 1900;
else
- YY += 2000;
+ tm->tm_year += 2000;
} else if (tag == ASN1_GENTIM) {
/* GenTime: YYYYMMDDHHMMSSZ */
if (vlen != 15)
goto unsupported_time;
- YY = DD2bin(p) * 100 + DD2bin(p);
+ tm->tm_year = DD2bin(p) * 100 + DD2bin(p);
} else {
goto unsupported_time;
}
- MM = DD2bin(p);
- DD = DD2bin(p);
- hh = DD2bin(p);
- mm = DD2bin(p);
- ss = DD2bin(p);
+ tm->tm_year -= 1900;
+ tm->tm_mon = DD2bin(p) - 1;
+ tm->tm_mday = DD2bin(p);
+ tm->tm_hour = DD2bin(p);
+ tm->tm_min = DD2bin(p);
+ tm->tm_sec = DD2bin(p);
if (*p != 'Z')
goto unsupported_time;
- *_time = mktime(YY, MM, DD, hh, mm, ss);
return 0;
unsupported_time:
diff --git a/crypto/asymmetric_keys/x509_parser.h b/crypto/asymmetric_keys/x509_parser.h
index 635053f..f86dc5f 100644
--- a/crypto/asymmetric_keys/x509_parser.h
+++ b/crypto/asymmetric_keys/x509_parser.h
@@ -18,8 +18,8 @@
char *subject; /* Name of certificate subject */
char *fingerprint; /* Key fingerprint as hex */
char *authority; /* Authority key fingerprint as hex */
- time_t valid_from;
- time_t valid_to;
+ struct tm valid_from;
+ struct tm valid_to;
enum pkey_algo pkey_algo : 8; /* Public key algorithm */
enum pkey_algo sig_pkey_algo : 8; /* Signature public key algorithm */
enum pkey_hash_algo sig_hash_algo : 8; /* Signature hash algorithm */
diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c
index 716917c..5ab736d 100644
--- a/crypto/asymmetric_keys/x509_public_key.c
+++ b/crypto/asymmetric_keys/x509_public_key.c
@@ -106,7 +106,7 @@
static int x509_key_preparse(struct key_preparsed_payload *prep)
{
struct x509_certificate *cert;
- time_t now;
+ struct tm now;
size_t srlen, sulen;
char *desc = NULL;
int ret;
@@ -118,7 +118,14 @@
pr_devel("Cert Issuer: %s\n", cert->issuer);
pr_devel("Cert Subject: %s\n", cert->subject);
pr_devel("Cert Key Algo: %s\n", pkey_algo[cert->pkey_algo]);
- pr_devel("Cert Valid: %lu - %lu\n", cert->valid_from, cert->valid_to);
+ printk("Cert Valid From: %04ld-%02d-%02d %02d:%02d:%02d\n",
+ cert->valid_from.tm_year + 1900, cert->valid_from.tm_mon + 1,
+ cert->valid_from.tm_mday, cert->valid_from.tm_hour,
+ cert->valid_from.tm_min, cert->valid_from.tm_sec);
+ printk("Cert Valid To: %04ld-%02d-%02d %02d:%02d:%02d\n",
+ cert->valid_to.tm_year + 1900, cert->valid_to.tm_mon + 1,
+ cert->valid_to.tm_mday, cert->valid_to.tm_hour,
+ cert->valid_to.tm_min, cert->valid_to.tm_sec);
pr_devel("Cert Signature: %s + %s\n",
pkey_algo[cert->sig_pkey_algo],
pkey_hash_algo[cert->sig_hash_algo]);
@@ -130,13 +137,38 @@
goto error_free_cert;
}
- now = CURRENT_TIME.tv_sec;
- if (now < cert->valid_from) {
+ time_to_tm(CURRENT_TIME.tv_sec, 0, &now);
+ printk("Now: %04ld-%02d-%02d %02d:%02d:%02d\n",
+ now.tm_year + 1900, now.tm_mon + 1, now.tm_mday,
+ now.tm_hour, now.tm_min, now.tm_sec);
+ if (now.tm_year < cert->valid_from.tm_year ||
+ (now.tm_year == cert->valid_from.tm_year &&
+ (now.tm_mon < cert->valid_from.tm_mon ||
+ (now.tm_mon == cert->valid_from.tm_mon &&
+ (now.tm_mday < cert->valid_from.tm_mday ||
+ (now.tm_mday == cert->valid_from.tm_mday &&
+ (now.tm_hour < cert->valid_from.tm_hour ||
+ (now.tm_hour == cert->valid_from.tm_hour &&
+ (now.tm_min < cert->valid_from.tm_min ||
+ (now.tm_min == cert->valid_from.tm_min &&
+ (now.tm_sec < cert->valid_from.tm_sec
+ ))))))))))) {
pr_warn("Cert %s is not yet valid\n", cert->fingerprint);
ret = -EKEYREJECTED;
goto error_free_cert;
}
- if (now >= cert->valid_to) {
+ if (now.tm_year > cert->valid_to.tm_year ||
+ (now.tm_year == cert->valid_to.tm_year &&
+ (now.tm_mon > cert->valid_to.tm_mon ||
+ (now.tm_mon == cert->valid_to.tm_mon &&
+ (now.tm_mday > cert->valid_to.tm_mday ||
+ (now.tm_mday == cert->valid_to.tm_mday &&
+ (now.tm_hour > cert->valid_to.tm_hour ||
+ (now.tm_hour == cert->valid_to.tm_hour &&
+ (now.tm_min > cert->valid_to.tm_min ||
+ (now.tm_min == cert->valid_to.tm_min &&
+ (now.tm_sec > cert->valid_to.tm_sec
+ ))))))))))) {
pr_warn("Cert %s has expired\n", cert->fingerprint);
ret = -EKEYEXPIRED;
goto error_free_cert;