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TLS 13 session ticket timeout: fixup checks

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Check difference between now and ticket seen from encrypted ticket
against timeout.
This commit is contained in:
Sean Parkinson
2021-12-09 12:43:30 +10:00
parent 85ec6054c6
commit 32014c69fd
2 changed files with 21 additions and 14 deletions
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22
src/tls13.c
View File

@ -3988,21 +3988,27 @@ static int DoPreSharedKeys(WOLFSSL* ssl, byte* suite, int* usingPSK, int* first)
if (DoClientTicket(ssl, current->identity, current->identityLen)
== WOLFSSL_TICKET_RET_OK) {
word32 now;
int diff;
sword64 diff;
now = TimeNowInMilliseconds();
if (now == (word32)GETTIME_ERROR)
return now;
if (now < ssl->session.ticketSeen)
diff = (0xFFFFFFFFU - ssl->session.ticketSeen) + 1 + now;
else
diff = now - ssl->session.ticketSeen;
diff -= current->ticketAge - ssl->session.ticketAdd;
/* Difference between now and time ticket constructed
* (from decrypted ticket). */
diff = now;
diff -= ssl->session.ticketSeen;
if (diff > (sword64)ssl->timeout * 1000 ||
diff > (sword64)TLS13_MAX_TICKET_AGE * 1000) {
current = current->next;
continue;
}
/* Subtract client's ticket age and unobfuscate. */
diff -= current->ticketAge;
diff += ssl->session.ticketAdd;
/* Check session and ticket age timeout.
* Allow +/- 1000 milliseconds on ticket age.
*/
if (diff > (int)ssl->timeout * 1000 || diff < -1000 ||
diff - MAX_TICKET_AGE_SECS * 1000 > 1000) {
if (diff < -1000 || diff - MAX_TICKET_AGE_DIFF * 1000 > 1000) {
current = current->next;
continue;
}

3
wolfssl/internal.h
View File

@ -1494,7 +1494,8 @@ enum Misc {
MAX_PSK_KEY_LEN = 64, /* max psk key supported */
MIN_PSK_ID_LEN = 6, /* min length of identities */
MIN_PSK_BINDERS_LEN = 33, /* min length of binders */
MAX_TICKET_AGE_SECS= 10, /* maximum ticket age in seconds */
MAX_TICKET_AGE_DIFF = 10, /* maximum ticket age difference in seconds */
TLS13_MAX_TICKET_AGE = 7*24*60*60, /* max ticket age in seconds, 7 days */
#ifndef MAX_WOLFSSL_FILE_SIZE
MAX_WOLFSSL_FILE_SIZE = 1024ul * 1024ul * 4, /* 4 mb file size alloc limit */