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TLS: SSL_peek is not a const operation

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Calling SSL_peek can cause bytes to be read from the raw socket which in
turn can upset the select machinery that determines whether there's data
available on the socket.

Since Curl_ossl_check_cxn only tries to determine whether the socket is
alive and doesn't actually need to see the bytes SSL_peek seems like
the wrong function to call.

We're able to occasionally reproduce a connect timeout due to this
bug. What happens is that Curl doesn't know to call SSL_connect again
after the peek happens since data is buffered in the SSL buffer and thus
select won't fire for this socket.

Closes #795
This commit is contained in:
Anders Bakken 2016-05-10 12:49:33 -07:00 committed by Daniel Stenberg
parent f6767f5435
commit 856baf5a46
1 changed files with 8 additions and 8 deletions
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16
lib/vtls/openssl.c
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@ -759,17 +759,17 @@ void Curl_ossl_cleanup(void)
*/
int Curl_ossl_check_cxn(struct connectdata *conn)
{
int rc;
#ifdef MSG_PEEK
char buf;
rc = SSL_peek(conn->ssl[FIRSTSOCKET].handle, (void*)&buf, 1);
if(rc > 0)
return 1; /* connection still in place */
if(rc == 0)
if(recv((RECV_TYPE_ARG1)conn->sock[FIRSTSOCKET], (RECV_TYPE_ARG2)&buf,
(RECV_TYPE_ARG3)1, (RECV_TYPE_ARG4)MSG_PEEK) == 0) {
return 0; /* connection has been closed */
}
else
return 1; /* connection still in place */
#else
return -1; /* connection status unknown */
#endif
}
/* Selects an OpenSSL crypto engine