X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/3ecab1575ef1f45a5e7cd3c48cd937ffa8eb0ad9..b4f579d134197249b448cb5d8abf801ba4c729bb:/src/src/tls.c diff --git a/src/src/tls.c b/src/src/tls.c index 0c98aeba9..796bc6d61 100644 --- a/src/src/tls.c +++ b/src/src/tls.c @@ -2,13 +2,13 @@ * Exim - an Internet mail transport agent * *************************************************/ -/* Copyright (c) University of Cambridge 1995 - 2012 */ +/* Copyright (c) University of Cambridge 1995 - 2018 */ /* See the file NOTICE for conditions of use and distribution. */ /* This module provides TLS (aka SSL) support for Exim. The code for OpenSSL is based on a patch that was originally contributed by Steve Haslam. It was adapted from stunnel, a GPL program by Michal Trojnara. The code for GNU TLS is -based on a patch contributed by Nikos Mavroyanopoulos. Because these packages +based on a patch contributed by Nikos Mavrogiannopoulos. Because these packages are so very different, the functions for each are kept in separate files. The relevant file is #included as required, after any any common functions. @@ -17,6 +17,23 @@ functions from the OpenSSL or GNU TLS libraries. */ #include "exim.h" +#include "transports/smtp.h" + +#if !defined(DISABLE_TLS) && !defined(USE_OPENSSL) && !defined(USE_GNUTLS) +# error One of USE_OPENSSL or USE_GNUTLS must be defined for a TLS build +#endif + + +#if defined(MACRO_PREDEF) && !defined(DISABLE_TLS) +# include "macro_predef.h" +# ifdef USE_GNUTLS +# include "tls-gnu.c" +# else +# include "tls-openssl.c" +# endif +#endif + +#ifndef MACRO_PREDEF /* This module is compiled only when it is specifically requested in the build-time configuration. However, some compilers don't like compiling empty @@ -25,7 +42,7 @@ reference itself to stop picky compilers complaining that it is unused, and put in a dummy argument to stop even pickier compilers complaining about infinite loops. */ -#ifndef SUPPORT_TLS +#ifdef DISABLE_TLS static void dummy(int x) { dummy(x-1); } #else @@ -36,12 +53,12 @@ We're moving away from this; GnuTLS is already using a state, which can switch, so we can do TLS callouts during ACLs. */ static const int ssl_xfer_buffer_size = 4096; -#ifndef USE_GNUTLS +#ifdef USE_OPENSSL static uschar *ssl_xfer_buffer = NULL; static int ssl_xfer_buffer_lwm = 0; static int ssl_xfer_buffer_hwm = 0; -static int ssl_xfer_eof = 0; -static int ssl_xfer_error = 0; +static int ssl_xfer_eof = FALSE; +static BOOL ssl_xfer_error = FALSE; #endif uschar *tls_channelbinding_b64 = NULL; @@ -63,37 +80,63 @@ Returns: TRUE if OK; result may still be NULL after forced failure */ static BOOL -expand_check(const uschar *s, const uschar *name, uschar **result) +expand_check(const uschar *s, const uschar *name, uschar **result, uschar ** errstr) { -if (s == NULL) *result = NULL; else +if (!s) + *result = NULL; +else if ( !(*result = expand_string(US s)) /* need to clean up const more */ + && !f.expand_string_forcedfail + ) { - *result = expand_string(US s); /* need to clean up const some more */ - if (*result == NULL && !expand_string_forcedfail) - { - log_write(0, LOG_MAIN|LOG_PANIC, "expansion of %s failed: %s", name, - expand_string_message); - return FALSE; - } + *errstr = US"Internal error"; + log_write(0, LOG_MAIN|LOG_PANIC, "expansion of %s failed: %s", name, + expand_string_message); + return FALSE; } return TRUE; } +/************************************************* +* Timezone environment flipping * +*************************************************/ + +static uschar * +to_tz(uschar * tz) +{ +uschar * old = US getenv("TZ"); +(void) setenv("TZ", CCS tz, 1); +tzset(); +return old; +} + +static void +restore_tz(uschar * tz) +{ +if (tz) + (void) setenv("TZ", CCS tz, 1); +else + (void) os_unsetenv(US"TZ"); +tzset(); +} + /************************************************* * Many functions are package-specific * *************************************************/ #ifdef USE_GNUTLS -#include "tls-gnu.c" - -#define ssl_xfer_buffer (current_global_tls_state->xfer_buffer) -#define ssl_xfer_buffer_lwm (current_global_tls_state->xfer_buffer_lwm) -#define ssl_xfer_buffer_hwm (current_global_tls_state->xfer_buffer_hwm) -#define ssl_xfer_eof (current_global_tls_state->xfer_eof) -#define ssl_xfer_error (current_global_tls_state->xfer_error) +# include "tls-gnu.c" +# include "tlscert-gnu.c" +# define ssl_xfer_buffer (state_server.xfer_buffer) +# define ssl_xfer_buffer_lwm (state_server.xfer_buffer_lwm) +# define ssl_xfer_buffer_hwm (state_server.xfer_buffer_hwm) +# define ssl_xfer_eof (state_server.xfer_eof) +# define ssl_xfer_error (state_server.xfer_error) +#endif -#else -#include "tls-openssl.c" +#ifdef USE_OPENSSL +# include "tls-openssl.c" +# include "tlscert-openssl.c" #endif @@ -104,6 +147,7 @@ return TRUE; /* Puts a character back in the input buffer. Only ever called once. +Only used by the server-side TLS. Arguments: ch the character @@ -125,6 +169,7 @@ return ch; *************************************************/ /* Tests for a previous EOF +Only used by the server-side TLS. Arguments: none Returns: non-zero if the eof flag is set @@ -133,7 +178,7 @@ Returns: non-zero if the eof flag is set int tls_feof(void) { -return ssl_xfer_eof; +return (int)ssl_xfer_eof; } @@ -144,6 +189,7 @@ return ssl_xfer_eof; /* Tests for a previous read error, and returns with errno restored to what it was when the error was detected. +Only used by the server-side TLS. >>>>> Hmm. Errno not handled yet. Where do we get it from? >>>>> @@ -154,7 +200,7 @@ Returns: non-zero if the error flag is set int tls_ferror(void) { -return ssl_xfer_error; +return (int)ssl_xfer_error; } @@ -163,6 +209,7 @@ return ssl_xfer_error; *************************************************/ /* Tests for unused chars in the TLS input buffer. +Only used by the server-side TLS. Arguments: none Returns: TRUE/FALSE @@ -175,6 +222,156 @@ return ssl_xfer_buffer_lwm < ssl_xfer_buffer_hwm; } -#endif /* SUPPORT_TLS */ +#endif /*DISABLE_TLS*/ + +void +tls_modify_variables(tls_support * dest_tsp) +{ +modify_variable(US"tls_bits", &dest_tsp->bits); +modify_variable(US"tls_certificate_verified", &dest_tsp->certificate_verified); +modify_variable(US"tls_cipher", &dest_tsp->cipher); +modify_variable(US"tls_peerdn", &dest_tsp->peerdn); +#ifdef USE_OPENSSL +modify_variable(US"tls_sni", &dest_tsp->sni); +#endif +} + + +#ifndef DISABLE_TLS +/************************************************ +* TLS certificate name operations * +************************************************/ + +/* Convert an rfc4514 DN to an exim comma-sep list. +Backslashed commas need to be replaced by doublecomma +for Exim's list quoting. We modify the given string +inplace. +*/ + +static void +dn_to_list(uschar * dn) +{ +for (uschar * cp = dn; *cp; cp++) + if (cp[0] == '\\' && cp[1] == ',') + *cp++ = ','; +} + + +/* Extract fields of a given type from an RFC4514- +format Distinguished Name. Return an Exim list. +NOTE: We modify the supplied dn string during operation. +Arguments: + dn Distinguished Name string + mod list containing optional output list-sep and + field selector match, comma-separated +Return: + allocated string with list of matching fields, + field type stripped +*/ + +uschar * +tls_field_from_dn(uschar * dn, const uschar * mod) +{ +int insep = ','; +uschar outsep = '\n'; +uschar * ele; +uschar * match = NULL; +int len; +gstring * list = NULL; + +while ((ele = string_nextinlist(&mod, &insep, NULL, 0))) + if (ele[0] != '>') + match = ele; /* field tag to match */ + else if (ele[1]) + outsep = ele[1]; /* nondefault output separator */ + +dn_to_list(dn); +insep = ','; +len = match ? Ustrlen(match) : -1; +while ((ele = string_nextinlist(CUSS &dn, &insep, NULL, 0))) + if ( !match + || Ustrncmp(ele, match, len) == 0 && ele[len] == '=' + ) + list = string_append_listele(list, outsep, ele+len+1); +return string_from_gstring(list); +} + + +/* Compare a domain name with a possibly-wildcarded name. Wildcards +are restricted to a single one, as the first element of patterns +having at least three dot-separated elements. Case-independent. +Return TRUE for a match +*/ +static BOOL +is_name_match(const uschar * name, const uschar * pat) +{ +uschar * cp; +return *pat == '*' /* possible wildcard match */ + ? *++pat == '.' /* starts star, dot */ + && !Ustrchr(++pat, '*') /* has no more stars */ + && Ustrchr(pat, '.') /* and has another dot. */ + && (cp = Ustrchr(name, '.'))/* The name has at least one dot */ + && strcmpic(++cp, pat) == 0 /* and we only compare after it. */ + : !Ustrchr(pat+1, '*') + && strcmpic(name, pat) == 0; +} + +/* Compare a list of names with the dnsname elements +of the Subject Alternate Name, if any, and the +Subject otherwise. + +Arguments: + namelist names to compare + cert certificate + +Returns: + TRUE/FALSE +*/ + +BOOL +tls_is_name_for_cert(const uschar * namelist, void * cert) +{ +uschar * altnames = tls_cert_subject_altname(cert, US"dns"); +uschar * subjdn; +uschar * certname; +int cmp_sep = 0; +uschar * cmpname; + +if ((altnames = tls_cert_subject_altname(cert, US"dns"))) + { + int alt_sep = '\n'; + while ((cmpname = string_nextinlist(&namelist, &cmp_sep, NULL, 0))) + { + const uschar * an = altnames; + while ((certname = string_nextinlist(&an, &alt_sep, NULL, 0))) + if (is_name_match(cmpname, certname)) + return TRUE; + } + } + +else if ((subjdn = tls_cert_subject(cert, NULL))) + { + int sn_sep = ','; + + dn_to_list(subjdn); + while ((cmpname = string_nextinlist(&namelist, &cmp_sep, NULL, 0))) + { + const uschar * sn = subjdn; + while ((certname = string_nextinlist(&sn, &sn_sep, NULL, 0))) + if ( *certname++ == 'C' + && *certname++ == 'N' + && *certname++ == '=' + && is_name_match(cmpname, certname) + ) + return TRUE; + } + } +return FALSE; +} +#endif /*!DISABLE_TLS*/ +#endif /*!MACRO_PREDEF*/ + +/* vi: aw ai sw=2 +*/ /* End of tls.c */