On Tue Dec 02 17:31:05 2014, [email protected] wrote: > if you send patch i can add it to SRPM build and try results > The patch is attached. However you may have problems with this approach. I have built the patch for 1.0.1e (which is the version you originally said you were running). However any additional patches that have been applied to the SRPM could cause the patch to fail to apply (and it is quite a large patch). I can also supply a patch against the latest 1.0.1j or OpenSSL_1_0_1-stable from git if you prefer.
Matt
>From a0473d82c6ad0d4f5f1e2f778a20ae374317720a Mon Sep 17 00:00:00 2001 From: Matt Caswell <[email protected]> Date: Mon, 1 Dec 2014 11:10:38 +0000 Subject: [PATCH] MTU fixes patch --- apps/s_client.c | 16 +++++++- apps/s_server.c | 18 ++++++++- crypto/bio/bio.h | 4 ++ crypto/bio/bss_dgram.c | 46 ++++++++++++++++++++-- ssl/d1_both.c | 103 +++++++++++++++++++++++++++++++------------------ ssl/d1_lib.c | 32 +++++++++++++-- ssl/dtls1.h | 4 ++ ssl/ssl.h | 8 ++++ ssl/ssl_lib.c | 13 ------- ssl/ssl_locl.h | 3 +- 10 files changed, 184 insertions(+), 63 deletions(-) diff --git a/apps/s_client.c b/apps/s_client.c index 3ba6605..9f4be61 100644 --- a/apps/s_client.c +++ b/apps/s_client.c @@ -1307,10 +1307,22 @@ re_start: BIO_ctrl(sbio, BIO_CTRL_DGRAM_SET_SEND_TIMEOUT, 0, &timeout); } - if (socket_mtu > 28) + if (socket_mtu) { + if(socket_mtu < DTLS_get_link_min_mtu(con)) + { + BIO_printf(bio_err,"MTU too small. Must be at least %d\n", + DTLS_get_link_min_mtu(con)); + BIO_free(sbio); + goto shut; + } SSL_set_options(con, SSL_OP_NO_QUERY_MTU); - SSL_set_mtu(con, socket_mtu - 28); + if(!DTLS_set_link_mtu(con, socket_mtu)) + { + BIO_printf(bio_err, "Failed to set MTU\n"); + BIO_free(sbio); + goto shut; + } } else /* want to do MTU discovery */ diff --git a/apps/s_server.c b/apps/s_server.c index 8198d7f..a6f090b 100644 --- a/apps/s_server.c +++ b/apps/s_server.c @@ -2035,10 +2035,24 @@ static int sv_body(char *hostname, int s, unsigned char *context) BIO_ctrl(sbio, BIO_CTRL_DGRAM_SET_SEND_TIMEOUT, 0, &timeout); } - if (socket_mtu > 28) + if (socket_mtu) { + if(socket_mtu < DTLS_get_link_min_mtu(con)) + { + BIO_printf(bio_err,"MTU too small. Must be at least %d\n", + DTLS_get_link_min_mtu(con)); + ret = -1; + BIO_free(sbio); + goto err; + } SSL_set_options(con, SSL_OP_NO_QUERY_MTU); - SSL_set_mtu(con, socket_mtu - 28); + if(!DTLS_set_link_mtu(con, socket_mtu)) + { + BIO_printf(bio_err, "Failed to set MTU\n"); + ret = -1; + BIO_free(sbio); + goto err; + } } else /* want to do MTU discovery */ diff --git a/crypto/bio/bio.h b/crypto/bio/bio.h index 05699ab..32eba71 100644 --- a/crypto/bio/bio.h +++ b/crypto/bio/bio.h @@ -175,6 +175,8 @@ extern "C" { #define BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT 45 /* Next DTLS handshake timeout to * adjust socket timeouts */ +#define BIO_CTRL_DGRAM_GET_MTU_OVERHEAD 49 + #ifndef OPENSSL_NO_SCTP /* SCTP stuff */ #define BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE 50 @@ -607,6 +609,8 @@ int BIO_ctrl_reset_read_request(BIO *b); (int)BIO_ctrl(b, BIO_CTRL_DGRAM_GET_PEER, 0, (char *)peer) #define BIO_dgram_set_peer(b,peer) \ (int)BIO_ctrl(b, BIO_CTRL_DGRAM_SET_PEER, 0, (char *)peer) +#define BIO_dgram_get_mtu_overhead(b) \ + (unsigned int)BIO_ctrl((b), BIO_CTRL_DGRAM_GET_MTU_OVERHEAD, 0, NULL) /* These two aren't currently implemented */ /* int BIO_get_ex_num(BIO *bio); */ diff --git a/crypto/bio/bss_dgram.c b/crypto/bio/bss_dgram.c index 8990909..0e5a52f 100644 --- a/crypto/bio/bss_dgram.c +++ b/crypto/bio/bss_dgram.c @@ -454,6 +454,36 @@ static int dgram_write(BIO *b, const char *in, int inl) return(ret); } +static long dgram_get_mtu_overhead(bio_dgram_data *data) + { + long ret; + + switch (data->peer.sa.sa_family) + { + case AF_INET: + /* Assume this is UDP - 20 bytes for IP, 8 bytes for UDP */ + ret = 28; + break; +#if OPENSSL_USE_IPV6 + case AF_INET6: +#ifdef IN6_IS_ADDR_V4MAPPED + if (IN6_IS_ADDR_V4MAPPED(&data->peer.sa_in6.sin6_addr)) + /* Assume this is UDP - 20 bytes for IP, 8 bytes for UDP */ + ret = 28; + else +#endif + /* Assume this is UDP - 40 bytes for IP, 8 bytes for UDP */ + ret = 48; + break; +#endif + default: + /* We don't know. Go with the historical default */ + ret = 28; + break; + } + return ret; + } + static long dgram_ctrl(BIO *b, int cmd, long num, void *ptr) { long ret=1; @@ -630,23 +660,24 @@ static long dgram_ctrl(BIO *b, int cmd, long num, void *ptr) #endif break; case BIO_CTRL_DGRAM_GET_FALLBACK_MTU: + ret = -dgram_get_mtu_overhead(data); switch (data->peer.sa.sa_family) { case AF_INET: - ret = 576 - 20 - 8; + ret += 576; break; #if OPENSSL_USE_IPV6 case AF_INET6: #ifdef IN6_IS_ADDR_V4MAPPED if (IN6_IS_ADDR_V4MAPPED(&data->peer.sa_in6.sin6_addr)) - ret = 576 - 20 - 8; + ret += 576; else #endif - ret = 1280 - 40 - 8; + ret += 1280; break; #endif default: - ret = 576 - 20 - 8; + ret += 576; break; } break; @@ -847,6 +878,9 @@ static long dgram_ctrl(BIO *b, int cmd, long num, void *ptr) ret = 0; break; #endif + case BIO_CTRL_DGRAM_GET_MTU_OVERHEAD: + ret = dgram_get_mtu_overhead(data); + break; default: ret=0; break; @@ -1367,6 +1401,10 @@ static long dgram_sctp_ctrl(BIO *b, int cmd, long num, void *ptr) * Returns always 1. */ break; + case BIO_CTRL_DGRAM_GET_MTU_OVERHEAD: + /* We allow transport protocol fragmentation so this is irrelevant */ + ret = 0; + break; case BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE: if (num > 0) data->in_handshake = 1; diff --git a/ssl/d1_both.c b/ssl/d1_both.c index de8bab8..0781ca5 100644 --- a/ssl/d1_both.c +++ b/ssl/d1_both.c @@ -156,9 +156,8 @@ static unsigned char bitmask_start_values[] = {0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe static unsigned char bitmask_end_values[] = {0xff, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f}; /* XDTLS: figure out the right values */ -static unsigned int g_probable_mtu[] = {1500 - 28, 512 - 28, 256 - 28}; +static const unsigned int g_probable_mtu[] = {1500, 512, 256}; -static unsigned int dtls1_guess_mtu(unsigned int curr_mtu); static void dtls1_fix_message_header(SSL *s, unsigned long frag_off, unsigned long frag_len); static unsigned char *dtls1_write_message_header(SSL *s, @@ -219,29 +218,48 @@ dtls1_hm_fragment_free(hm_fragment *frag) OPENSSL_free(frag); } +static int dtls1_query_mtu(SSL *s) +{ + if(s->d1->link_mtu) + { + s->d1->mtu = s->d1->link_mtu-BIO_dgram_get_mtu_overhead(SSL_get_wbio(s)); + s->d1->link_mtu = 0; + } + + /* AHA! Figure out the MTU, and stick to the right size */ + if (s->d1->mtu < dtls1_min_mtu(s)) + { + if(!(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) + { + s->d1->mtu = + BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL); + + /* I've seen the kernel return bogus numbers when it doesn't know + * (initial write), so just make sure we have a reasonable number */ + if (s->d1->mtu < dtls1_min_mtu(s)) + { + /* Set to min mtu */ + s->d1->mtu = dtls1_min_mtu(s); + BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU, + s->d1->mtu, NULL); + } + } + else + return 0; + } + return 1; +} + /* send s->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or SSL3_RT_CHANGE_CIPHER_SPEC) */ int dtls1_do_write(SSL *s, int type) { int ret; int curr_mtu; + int retry = 1; unsigned int len, frag_off, mac_size, blocksize; - /* AHA! Figure out the MTU, and stick to the right size */ - if (s->d1->mtu < dtls1_min_mtu() && !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) - { - s->d1->mtu = - BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL); - - /* I've seen the kernel return bogus numbers when it doesn't know - * (initial write), so just make sure we have a reasonable number */ - if (s->d1->mtu < dtls1_min_mtu()) - { - s->d1->mtu = 0; - s->d1->mtu = dtls1_guess_mtu(s->d1->mtu); - BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU, - s->d1->mtu, NULL); - } - } + if(!dtls1_query_mtu(s)) + return -1; #if 0 mtu = s->d1->mtu; @@ -265,7 +283,7 @@ int dtls1_do_write(SSL *s, int type) } #endif - OPENSSL_assert(s->d1->mtu >= dtls1_min_mtu()); /* should have something reasonable now */ + OPENSSL_assert(s->d1->mtu >= dtls1_min_mtu(s)); /* should have something reasonable now */ if ( s->init_off == 0 && type == SSL3_RT_HANDSHAKE) OPENSSL_assert(s->init_num == @@ -318,12 +336,18 @@ int dtls1_do_write(SSL *s, int type) len += DTLS1_HM_HEADER_LENGTH; } + if ( len < DTLS1_HM_HEADER_LENGTH ) + { + /* + * len is so small that we really can't do anything sensible + * so fail + */ + return -1; + } dtls1_fix_message_header(s, frag_off, len - DTLS1_HM_HEADER_LENGTH); dtls1_write_message_header(s, (unsigned char *)&s->init_buf->data[s->init_off]); - - OPENSSL_assert(len >= DTLS1_HM_HEADER_LENGTH); } ret=dtls1_write_bytes(s,type,&s->init_buf->data[s->init_off], @@ -336,12 +360,23 @@ int dtls1_do_write(SSL *s, int type) * is fine and wait for an alert to handle the * retransmit */ - if ( BIO_ctrl(SSL_get_wbio(s), + if ( retry && BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_MTU_EXCEEDED, 0, NULL) > 0 ) - s->d1->mtu = BIO_ctrl(SSL_get_wbio(s), - BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL); + { + if(!(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) + { + if(!dtls1_query_mtu(s)) + return -1; + /* Have one more go */ + retry = 0; + } + else + return -1; + } else + { return(-1); + } } else { @@ -1380,28 +1415,20 @@ dtls1_write_message_header(SSL *s, unsigned char *p) return p; } -unsigned int -dtls1_min_mtu(void) +unsigned int +dtls1_link_min_mtu(void) { return (g_probable_mtu[(sizeof(g_probable_mtu) / sizeof(g_probable_mtu[0])) - 1]); } -static unsigned int -dtls1_guess_mtu(unsigned int curr_mtu) +unsigned int +dtls1_min_mtu(SSL *s) { - unsigned int i; - - if ( curr_mtu == 0 ) - return g_probable_mtu[0] ; - - for ( i = 0; i < sizeof(g_probable_mtu)/sizeof(g_probable_mtu[0]); i++) - if ( curr_mtu > g_probable_mtu[i]) - return g_probable_mtu[i]; - - return curr_mtu; + return dtls1_link_min_mtu()-BIO_dgram_get_mtu_overhead(SSL_get_wbio(s)); } + void dtls1_get_message_header(unsigned char *data, struct hm_header_st *msg_hdr) { diff --git a/ssl/d1_lib.c b/ssl/d1_lib.c index f61f718..87c36ad 100644 --- a/ssl/d1_lib.c +++ b/ssl/d1_lib.c @@ -113,6 +113,9 @@ int dtls1_new(SSL *s) d1->cookie_len = sizeof(s->d1->cookie); } + d1->link_mtu = 0; + d1->mtu = 0; + if( ! d1->unprocessed_rcds.q || ! d1->processed_rcds.q || ! d1->buffered_messages || ! d1->sent_messages || ! d1->buffered_app_data.q) { @@ -206,6 +209,7 @@ void dtls1_clear(SSL *s) pqueue sent_messages; pqueue buffered_app_data; unsigned int mtu; + unsigned int link_mtu; if (s->d1) { @@ -215,6 +219,7 @@ void dtls1_clear(SSL *s) sent_messages = s->d1->sent_messages; buffered_app_data = s->d1->buffered_app_data.q; mtu = s->d1->mtu; + link_mtu = s->d1->link_mtu; dtls1_clear_queues(s); @@ -228,6 +233,7 @@ void dtls1_clear(SSL *s) if (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU) { s->d1->mtu = mtu; + s->d1->link_mtu = link_mtu; } s->d1->unprocessed_rcds.q = unprocessed_rcds; @@ -262,7 +268,22 @@ long dtls1_ctrl(SSL *s, int cmd, long larg, void *parg) case DTLS_CTRL_LISTEN: ret = dtls1_listen(s, parg); break; - + case DTLS_CTRL_SET_LINK_MTU: + if (larg < (long)dtls1_link_min_mtu()) + return 0; + s->d1->link_mtu = larg; + return 1; + case DTLS_CTRL_GET_LINK_MIN_MTU: + return (long)dtls1_link_min_mtu(); + case SSL_CTRL_SET_MTU: + /* + * We may not have a BIO set yet so can't call dtls1_min_mtu() + * We'll have to make do with dtls1_link_min_mtu() and max overhead + */ + if (larg < (long)dtls1_link_min_mtu() - DTLS1_MAX_MTU_OVERHEAD) + return 0; + s->d1->mtu = larg; + return larg; default: ret = ssl3_ctrl(s, cmd, larg, parg); break; @@ -401,12 +422,17 @@ void dtls1_stop_timer(SSL *s) int dtls1_check_timeout_num(SSL *s) { + unsigned int mtu; + s->d1->timeout.num_alerts++; /* Reduce MTU after 2 unsuccessful retransmissions */ - if (s->d1->timeout.num_alerts > 2) + if (s->d1->timeout.num_alerts > 2 + && !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) { - s->d1->mtu = BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0, NULL); + mtu = BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0, NULL); + if(mtu < s->d1->mtu) + s->d1->mtu = mtu; } if (s->d1->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT) diff --git a/ssl/dtls1.h b/ssl/dtls1.h index e65d501..fd168e7 100644 --- a/ssl/dtls1.h +++ b/ssl/dtls1.h @@ -115,6 +115,9 @@ extern "C" { #define DTLS1_SCTP_AUTH_LABEL "EXPORTER_DTLS_OVER_SCTP" #endif +/* Max MTU overhead we know about so far is 40 for IPv6 + 8 for UDP */ +#define DTLS1_MAX_MTU_OVERHEAD 48 + typedef struct dtls1_bitmap_st { unsigned long map; /* track 32 packets on 32-bit systems @@ -229,6 +232,7 @@ typedef struct dtls1_state_st /* Is set when listening for new connections with dtls1_listen() */ unsigned int listen; + unsigned int link_mtu; /* max on-the-wire DTLS packet size */ unsigned int mtu; /* max DTLS packet size */ struct hm_header_st w_msg_hdr; diff --git a/ssl/ssl.h b/ssl/ssl.h index 593579e..377ceff 100644 --- a/ssl/ssl.h +++ b/ssl/ssl.h @@ -672,6 +672,10 @@ struct ssl_session_st SSL_ctrl((ssl),SSL_CTRL_MODE,0,NULL) #define SSL_set_mtu(ssl, mtu) \ SSL_ctrl((ssl),SSL_CTRL_SET_MTU,(mtu),NULL) +#define DTLS_set_link_mtu(ssl, mtu) \ + SSL_ctrl((ssl),DTLS_CTRL_SET_LINK_MTU,(mtu),NULL) +#define DTLS_get_link_min_mtu(ssl) \ + SSL_ctrl((ssl),DTLS_CTRL_GET_LINK_MIN_MTU,0,NULL) #define SSL_get_secure_renegotiation_support(ssl) \ SSL_ctrl((ssl), SSL_CTRL_GET_RI_SUPPORT, 0, NULL) @@ -1609,6 +1613,10 @@ DECLARE_PEM_rw(SSL_SESSION, SSL_SESSION) #define SSL_CTRL_GET_EXTRA_CHAIN_CERTS 82 #define SSL_CTRL_CLEAR_EXTRA_CHAIN_CERTS 83 + +#define DTLS_CTRL_SET_LINK_MTU 120 +#define DTLS_CTRL_GET_LINK_MIN_MTU 121 + #define DTLSv1_get_timeout(ssl, arg) \ SSL_ctrl(ssl,DTLS_CTRL_GET_TIMEOUT,0, (void *)arg) #define DTLSv1_handle_timeout(ssl) \ diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c index 14d143d..cd94f30 100644 --- a/ssl/ssl_lib.c +++ b/ssl/ssl_lib.c @@ -1080,19 +1080,6 @@ long SSL_ctrl(SSL *s,int cmd,long larg,void *parg) l=s->max_cert_list; s->max_cert_list=larg; return(l); - case SSL_CTRL_SET_MTU: -#ifndef OPENSSL_NO_DTLS1 - if (larg < (long)dtls1_min_mtu()) - return 0; -#endif - - if (SSL_version(s) == DTLS1_VERSION || - SSL_version(s) == DTLS1_BAD_VER) - { - s->d1->mtu = larg; - return larg; - } - return 0; case SSL_CTRL_SET_MAX_SEND_FRAGMENT: if (larg < 512 || larg > SSL3_RT_MAX_PLAIN_LENGTH) return 0; diff --git a/ssl/ssl_locl.h b/ssl/ssl_locl.h index 1b98947..7f4c375 100644 --- a/ssl/ssl_locl.h +++ b/ssl/ssl_locl.h @@ -983,7 +983,8 @@ void dtls1_stop_timer(SSL *s); int dtls1_is_timer_expired(SSL *s); void dtls1_double_timeout(SSL *s); int dtls1_send_newsession_ticket(SSL *s); -unsigned int dtls1_min_mtu(void); +unsigned int dtls1_min_mtu(SSL *s); +unsigned int dtls1_link_min_mtu(void); /* some client-only functions */ int ssl3_client_hello(SSL *s); -- 2.1.0
