From 85f48f7e93987a48da29877bd64258d88c5a4f99 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Bodo=20M=C3=B6ller?= Date: Thu, 22 Apr 1999 14:28:38 +0000 Subject: [PATCH] Don't return 0 from ssl2_read when a packet with empty payload is received. Submitted by: Reviewed by: PR: --- CHANGES | 4 ++++ ssl/s2_pkt.c | 21 +++++++++++++++++++++ 2 files changed, 25 insertions(+) diff --git a/CHANGES b/CHANGES index 15cba95ce0..a1b397867e 100644 --- a/CHANGES +++ b/CHANGES @@ -5,6 +5,10 @@ Changes between 0.9.2b and 0.9.3 + *) Change behaviour of ssl2_read when facing length-0 packets: Don't return + 0 (which usually indicates a closed connection), but continue reading. + [Bodo Moeller] + *) Fix some race conditions. [Bodo Moeller] diff --git a/ssl/s2_pkt.c b/ssl/s2_pkt.c index 89fe9dabb1..61b20305c1 100644 --- a/ssl/s2_pkt.c +++ b/ssl/s2_pkt.c @@ -104,6 +104,7 @@ int ssl2_read(SSL *s, char *buf, int len) int i; unsigned int mac_size=0; +ssl2_read_again: if (SSL_in_init(s) && !s->in_handshake) { n=s->handshake_func(s); @@ -231,6 +232,25 @@ int ssl2_read(SSL *s, char *buf, int len) INC32(s->s2->read_sequence); /* expect next number */ /* s->s2->ract_data is now available for processing */ +#if 1 + /* How should we react when a packet containing 0 + * bytes is received? (Note that SSLeay/OpenSSL itself + * never sends such packets; see ssl2_write.) + * Returning 0 would be interpreted by the caller as + * indicating EOF, so it's not a good idea. + * Instead, we just continue reading. Note that using + * select() for blocking sockets *never* guarantees + * that the next SSL_read will not block -- the available + * data may contain incomplete packets, and except for SSL 2 + * renegotiation can confuse things even more. */ + + goto ssl2_read_again; /* This should really be + * "return ssl2_read(s,buf,len)", + * but that would allow for + * denial-of-service attacks if a + * C compiler is used that does not + * recognize end-recursion. */ +#else /* If a 0 byte packet was sent, return 0, otherwise * we play havoc with people using select with * blocking sockets. Let them handle a packet at a time, @@ -238,6 +258,7 @@ int ssl2_read(SSL *s, char *buf, int len) if (s->s2->ract_data_length == 0) return(0); return(ssl2_read(s,buf,len)); +#endif } else { -- 2.34.1