modified for Gentoo, removed tests From e1aca33756f73c22b00a98d40ce2be8ed94464b1 Mon Sep 17 00:00:00 2001 From: Jeremy Harris Date: Thu, 5 Jan 2023 13:03:37 +0000 Subject: [PATCH 2/3] OpenSSL: log conns rejected for bad ALPN, with the offered value Unfortunately, no way to do this under GnuTLS --- src/match.c | 1 + src/tls-gnu.c | 9 ++++++++- src/tls-openssl.c | 13 +++++++++++-- test/log/1190 | 2 ++ test/runtest | 3 +++ 5 files changed, 25 insertions(+), 3 deletions(-) diff --git a/src/match.c b/src/match.c index 91a49c0f0..07070362d 100644 --- a/src/match.c +++ b/src/match.c @@ -968,6 +968,7 @@ Arguments: s string to search for listptr ptr to ptr to colon separated list of patterns, or NULL sep a separator value for the list (see string_nextinlist()) + or zero for auto anchorptr ptr to tree for named items, or NULL if no named items cache_bits ptr to cache_bits for ditto, or NULL if not caching type MCL_DOMAIN when matching a domain list diff --git a/src/tls-gnu.c b/src/tls-gnu.c index 729fb5879..b47fabf1d 100644 --- a/src/tls-gnu.c +++ b/src/tls-gnu.c @@ -1119,21 +1119,28 @@ switch (tls_id) /* The format of "data" here doesn't seem to be documented, but appears to be a 2-byte field with a (redundant, given the "size" arg) total length then a sequence of one-byte size then string (not nul-term) names. The - latter is as described in OpenSSL documentation. */ + latter is as described in OpenSSL documentation. + Note that we do not get called for a match_fail, making it hard to log + a single bad ALPN being offered (the common case). */ + { + gstring * g = NULL; DEBUG(D_tls) debug_printf("Seen ALPN extension from client (s=%u):", size); for (const uschar * s = data+2; s-data < size-1; s += *s + 1) { server_seen_alpn++; + g = string_append_listele_n(g, ':', s+1, *s); DEBUG(D_tls) debug_printf(" '%.*s'", (int)*s, s+1); } DEBUG(D_tls) debug_printf("\n"); if (server_seen_alpn > 1) { + log_write(0, LOG_MAIN, "TLS ALPN (%s) rejected", string_from_gstring(g)); DEBUG(D_tls) debug_printf("TLS: too many ALPNs presented in handshake\n"); return GNUTLS_E_NO_APPLICATION_PROTOCOL; } break; + } #endif } return 0; diff --git a/src/tls-openssl.c b/src/tls-openssl.c index e063d29bd..513ba0d3a 100644 --- a/src/tls-openssl.c +++ b/src/tls-openssl.c @@ -2324,6 +2324,8 @@ static int tls_server_alpn_cb(SSL *ssl, const uschar ** out, uschar * outlen, const uschar * in, unsigned int inlen, void * arg) { +gstring * g = NULL; + server_seen_alpn = TRUE; DEBUG(D_tls) { @@ -2354,12 +2356,19 @@ if ( inlen > 1 /* at least one name */ } } -/* More than one name from clilent, or name did not match our list. */ +/* More than one name from client, or name did not match our list. */ /* This will be fatal to the TLS conn; would be nice to kill TCP also. Maybe as an option in future; for now leave control to the config (must-tls). */ -DEBUG(D_tls) debug_printf("TLS ALPN rejected\n"); +for (int pos = 0, siz; pos < inlen; pos += siz+1) + { + siz = in[pos]; + if (pos + 1 + siz > inlen) siz = inlen - pos - 1; + g = string_append_listele_n(g, ':', in + pos + 1, siz); + } +log_write(0, LOG_MAIN, "TLS ALPN (%s) rejected", string_from_gstring(g)); +gstring_release_unused(g); return SSL_TLSEXT_ERR_ALERT_FATAL; } #endif /* EXIM_HAVE_ALPN */ -- 2.39.0