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-rw-r--r--debian/patches/90_localscan_dlopen.dpatch347
1 files changed, 347 insertions, 0 deletions
diff --git a/debian/patches/90_localscan_dlopen.dpatch b/debian/patches/90_localscan_dlopen.dpatch
new file mode 100644
index 0000000..21c96b1
--- /dev/null
+++ b/debian/patches/90_localscan_dlopen.dpatch
@@ -0,0 +1,347 @@
+Description: Allow one to use and switch between different local_scan functions
+ without recompiling exim.
+ http://marc.merlins.org/linux/exim/files/sa-exim-current/ Original patch from
+ David Woodhouse, modified first by Derrick 'dman' Hudson and then by Marc
+ MERLIN for SA-Exim and minor/major API version tracking
+Author: David Woodhouse, Derrick 'dman' Hudson, Marc MERLIN
+Origin: other, http://marc.merlins.org/linux/exim/files/sa-exim-current/
+Forwarded: https://bugs.exim.org/show_bug.cgi?id=2671
+Last-Update: 2022-12-19
+
+--- a/src/EDITME
++++ b/src/EDITME
+@@ -874,10 +874,25 @@ HEADERS_CHARSET="ISO-8859-1"
+ # as the traditional crypt() function.
+ # *** WARNING *** WARNING *** WARNING *** WARNING *** WARNING ***
+
+
+ #------------------------------------------------------------------------------
++# On systems which support dynamic loading of shared libraries, Exim can
++# load a local_scan function specified in its config file instead of having
++# to be recompiled with the desired local_scan function. For a full
++# description of the API to this function, see the Exim specification.
++
++DLOPEN_LOCAL_SCAN=yes
++
++# If you set DLOPEN_LOCAL_SCAN, then you need to include -rdynamic in the
++# linker flags. Without it, the loaded .so won't be able to access any
++# functions from exim.
++
++LDFLAGS += -rdynamic
++CFLAGS += -fvisibility=hidden
++
++#------------------------------------------------------------------------------
+ # The default distribution of Exim contains only the plain text form of the
+ # documentation. Other forms are available separately. If you want to install
+ # the documentation in "info" format, first fetch the Texinfo documentation
+ # sources from the ftp directory and unpack them, which should create files
+ # with the extension "texinfo" in the doc directory. You may find that the
+--- a/src/config.h.defaults
++++ b/src/config.h.defaults
+@@ -31,10 +31,12 @@ Do not put spaces between # and the 'def
+ #define AUTH_SPA
+ #define AUTH_TLS
+
+ #define AUTH_VARS 4
+
++#define DLOPEN_LOCAL_SCAN
++
+ #define BIN_DIRECTORY
+
+ #define CONFIGURE_FILE
+ #define CONFIGURE_FILE_USE_EUID
+ #define CONFIGURE_FILE_USE_NODE
+--- a/src/globals.c
++++ b/src/globals.c
+@@ -115,10 +115,14 @@ tls_support tls_out = {
+ uschar *dsn_envid = NULL;
+ int dsn_ret = 0;
+ const pcre2_code *regex_DSN = NULL;
+ uschar *dsn_advertise_hosts = NULL;
+
++#ifdef DLOPEN_LOCAL_SCAN
++uschar *local_scan_path = NULL;
++#endif
++
+ #ifndef DISABLE_TLS
+ BOOL gnutls_compat_mode = FALSE;
+ BOOL gnutls_allow_auto_pkcs11 = FALSE;
+ uschar *hosts_require_alpn = NULL;
+ uschar *openssl_options = NULL;
+--- a/src/globals.h
++++ b/src/globals.h
+@@ -153,10 +153,14 @@ extern uschar *tls_advertise_hosts; /
+ extern uschar *dsn_envid; /* DSN envid string */
+ extern int dsn_ret; /* DSN ret type*/
+ extern const pcre2_code *regex_DSN; /* For recognizing DSN settings */
+ extern uschar *dsn_advertise_hosts; /* host for which TLS is advertised */
+
++#ifdef DLOPEN_LOCAL_SCAN
++extern uschar *local_scan_path; /* Path to local_scan() library */
++#endif
++
+ /* Input-reading functions for messages, so we can use special ones for
+ incoming TCP/IP. */
+
+ extern int (*lwr_receive_getc)(unsigned);
+ extern uschar * (*lwr_receive_getbuf)(unsigned *);
+--- a/src/local_scan.c
++++ b/src/local_scan.c
+@@ -5,60 +5,136 @@
+ /* Copyright (c) University of Cambridge 1995 - 2009 */
+ /* Copyright (c) The Exim Maintainers 2021 */
+ /* See the file NOTICE for conditions of use and distribution. */
+
+
+-/******************************************************************************
+-This file contains a template local_scan() function that just returns ACCEPT.
+-If you want to implement your own version, you should copy this file to, say
+-Local/local_scan.c, and edit the copy. To use your version instead of the
+-default, you must set
+-
+-HAVE_LOCAL_SCAN=yes
+-LOCAL_SCAN_SOURCE=Local/local_scan.c
+-
+-in your Local/Makefile. This makes it easy to copy your version for use with
+-subsequent Exim releases.
+-
+-For a full description of the API to this function, see the Exim specification.
+-******************************************************************************/
+-
+-
+ /* This is the only Exim header that you should include. The effect of
+ including any other Exim header is not defined, and may change from release to
+ release. Use only the documented interface! */
+
+ #include "local_scan.h"
+
+-
+-/* This is a "do-nothing" version of a local_scan() function. The arguments
+-are:
+-
+- fd The file descriptor of the open -D file, which contains the
+- body of the message. The file is open for reading and
+- writing, but modifying it is dangerous and not recommended.
+-
+- return_text A pointer to an unsigned char* variable which you can set in
+- order to return a text string. It is initialized to NULL.
+-
+-The return values of this function are:
+-
+- LOCAL_SCAN_ACCEPT
+- The message is to be accepted. The return_text argument is
+- saved in $local_scan_data.
+-
+- LOCAL_SCAN_REJECT
+- The message is to be rejected. The returned text is used
+- in the rejection message.
+-
+- LOCAL_SCAN_TEMPREJECT
+- This specifies a temporary rejection. The returned text
+- is used in the rejection message.
+-*/
++#ifdef DLOPEN_LOCAL_SCAN
++#include <dlfcn.h>
++#include <stdlib.h>
++static int (*local_scan_fn)(int fd, uschar **return_text) = NULL;
++static int load_local_scan_library(void);
++#endif
+
+ int
+ local_scan(int fd, uschar **return_text)
+ {
+-return LOCAL_SCAN_ACCEPT;
++
++#ifdef DLOPEN_LOCAL_SCAN
++/* local_scan_path is defined AND not the empty string */
++if (local_scan_path && *local_scan_path)
++ {
++ if (!local_scan_fn)
++ {
++ if (!load_local_scan_library())
++ {
++ char *base_msg , *error_msg , *final_msg ;
++ int final_length = -1 ;
++
++ base_msg=US"Local configuration error - local_scan() library failure\n";
++ error_msg = dlerror() ;
++
++ final_length = strlen(base_msg) + strlen(error_msg) + 1 ;
++ final_msg = (char*)malloc( final_length*sizeof(char) ) ;
++ *final_msg = '\0' ;
++
++ strcat( final_msg , base_msg ) ;
++ strcat( final_msg , error_msg ) ;
++
++ *return_text = final_msg ;
++ return LOCAL_SCAN_TEMPREJECT;
++ }
++ }
++ return local_scan_fn(fd, return_text);
++ }
++else
++#endif
++ return LOCAL_SCAN_ACCEPT;
++}
++
++#ifdef DLOPEN_LOCAL_SCAN
++
++static int load_local_scan_library(void)
++{
++/* No point in keeping local_scan_lib since we'll never dlclose() anyway */
++void *local_scan_lib = NULL;
++int (*local_scan_version_fn)(void);
++int vers_maj;
++int vers_min;
++
++local_scan_lib = dlopen(local_scan_path, RTLD_NOW);
++if (!local_scan_lib)
++ {
++ log_write(0, LOG_MAIN|LOG_REJECT, "local_scan() library open failed - "
++ "message temporarily rejected");
++ return FALSE;
++ }
++
++local_scan_version_fn = dlsym(local_scan_lib, "local_scan_version_major");
++if (!local_scan_version_fn)
++ {
++ dlclose(local_scan_lib);
++ log_write(0, LOG_MAIN|LOG_REJECT, "local_scan() library doesn't contain "
++ "local_scan_version_major() function - message temporarily rejected");
++ return FALSE;
++ }
++
++/* The major number is increased when the ABI is changed in a non
++ backward compatible way. */
++vers_maj = local_scan_version_fn();
++
++local_scan_version_fn = dlsym(local_scan_lib, "local_scan_version_minor");
++if (!local_scan_version_fn)
++ {
++ dlclose(local_scan_lib);
++ log_write(0, LOG_MAIN|LOG_REJECT, "local_scan() library doesn't contain "
++ "local_scan_version_minor() function - message temporarily rejected");
++ return FALSE;
++ }
++
++/* The minor number is increased each time a new feature is added (in a
++ way that doesn't break backward compatibility) -- Marc */
++vers_min = local_scan_version_fn();
++
++
++if (vers_maj != LOCAL_SCAN_ABI_VERSION_MAJOR)
++ {
++ dlclose(local_scan_lib);
++ local_scan_lib = NULL;
++ log_write(0, LOG_MAIN|LOG_REJECT, "local_scan() has an incompatible major"
++ "version number, you need to recompile your module for this version"
++ "of exim (The module was compiled for version %d.%d and this exim provides"
++ "ABI version %d.%d)", vers_maj, vers_min, LOCAL_SCAN_ABI_VERSION_MAJOR,
++ LOCAL_SCAN_ABI_VERSION_MINOR);
++ return FALSE;
++ }
++else if (vers_min > LOCAL_SCAN_ABI_VERSION_MINOR)
++ {
++ dlclose(local_scan_lib);
++ local_scan_lib = NULL;
++ log_write(0, LOG_MAIN|LOG_REJECT, "local_scan() has an incompatible minor"
++ "version number, you need to recompile your module for this version"
++ "of exim (The module was compiled for version %d.%d and this exim provides"
++ "ABI version %d.%d)", vers_maj, vers_min, LOCAL_SCAN_ABI_VERSION_MAJOR,
++ LOCAL_SCAN_ABI_VERSION_MINOR);
++ return FALSE;
++ }
++
++local_scan_fn = dlsym(local_scan_lib, "local_scan");
++if (!local_scan_fn)
++ {
++ dlclose(local_scan_lib);
++ log_write(0, LOG_MAIN|LOG_REJECT, "local_scan() library doesn't contain "
++ "local_scan() function - message temporarily rejected");
++ return FALSE;
++ }
++return TRUE;
+ }
+
++#endif /* DLOPEN_LOCAL_SCAN */
++
+ /* End of local_scan.c */
+--- a/src/local_scan.h
++++ b/src/local_scan.h
+@@ -25,10 +25,11 @@ store.c
+ /* Some basic types that make some things easier, the Exim configuration
+ settings, and the store functions. */
+
+ #include <stdarg.h>
+ #include <sys/types.h>
++#pragma GCC visibility push(default)
+ #include "config.h"
+ #include "mytypes.h"
+ #include "store.h"
+
+
+@@ -164,10 +165,13 @@ extern const uschar *headers_charset; /
+ extern header_line *header_last; /* Final header */
+ extern header_line *header_list; /* First header */
+ extern BOOL host_checking; /* Set when checking a host */
+ extern uschar *interface_address; /* Interface for incoming call */
+ extern int interface_port; /* Port number for incoming call */
++#ifdef DLOPEN_LOCAL_SCAN
++extern uschar *local_scan_path;
++#endif
+ extern uschar *message_id; /* Internal id of message being handled */
+ extern uschar *received_protocol; /* Name of incoming protocol */
+ extern int recipients_count; /* Number of recipients */
+ extern recipient_item *recipients_list;/* List of recipient addresses */
+ extern unsigned char *sender_address; /* Sender address */
+@@ -234,6 +238,8 @@ extern uschar * string_copy_taint_functi
+ extern pid_t child_open_exim_function(int *, const uschar *);
+ extern pid_t child_open_exim2_function(int *, uschar *, uschar *, const uschar *);
+ extern pid_t child_open_function(uschar **, uschar **, int, int *, int *, BOOL, const uschar *);
+ #endif
+
++#pragma GCC visibility pop
++
+ /* End of local_scan.h */
+--- a/src/readconf.c
++++ b/src/readconf.c
+@@ -210,10 +210,13 @@ static optionlist optionlist_config[] =
+ #endif
+ { "local_from_check", opt_bool, {&local_from_check} },
+ { "local_from_prefix", opt_stringptr, {&local_from_prefix} },
+ { "local_from_suffix", opt_stringptr, {&local_from_suffix} },
+ { "local_interfaces", opt_stringptr, {&local_interfaces} },
++#ifdef DLOPEN_LOCAL_SCAN
++ { "local_scan_path", opt_stringptr, &local_scan_path },
++#endif
+ #ifdef HAVE_LOCAL_SCAN
+ { "local_scan_timeout", opt_time, {&local_scan_timeout} },
+ #endif
+ { "local_sender_retain", opt_bool, {&local_sender_retain} },
+ { "localhost_number", opt_stringptr, {&host_number_string} },
+--- a/src/string.c
++++ b/src/string.c
+@@ -416,10 +416,11 @@ return ss;
+
+
+
+ #if (defined(HAVE_LOCAL_SCAN) || defined(EXPAND_DLFUNC)) \
+ && !defined(MACRO_PREDEF) && !defined(COMPILE_UTILITY)
++#pragma GCC visibility push(default)
+ /*************************************************
+ * Copy and save string *
+ *************************************************/
+
+ /*
+@@ -461,10 +462,11 @@ Returns: copy of string in new store
+ uschar *
+ string_copyn_function(const uschar * s, int n)
+ {
+ return string_copyn(s, n);
+ }
++#pragma GCC visibility pop
+ #endif
+
+
+ /*************************************************
+ * Copy and save string in malloc'd store *