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-rw-r--r--src/local/dotforward.c304
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diff --git a/src/local/dotforward.c b/src/local/dotforward.c
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+/*++
+/* NAME
+/* dotforward 3
+/* SUMMARY
+/* $HOME/.forward file expansion
+/* SYNOPSIS
+/* #include "local.h"
+/*
+/* int deliver_dotforward(state, usr_attr, statusp)
+/* LOCAL_STATE state;
+/* USER_ATTR usr_attr;
+/* int *statusp;
+/* DESCRIPTION
+/* deliver_dotforward() delivers a message to the destinations
+/* listed in a recipient's .forward file(s) as specified through
+/* the forward_path configuration parameter. The result is
+/* zero when no acceptable .forward file was found, or when
+/* a recipient is listed in her own .forward file. Expansions
+/* are scrutinized with the forward_expansion_filter parameter.
+/*
+/* Arguments:
+/* .IP state
+/* Message delivery attributes (sender, recipient etc.).
+/* Attributes describing alias, include or forward expansion.
+/* A table with the results from expanding aliases or lists.
+/* A table with delivered-to: addresses taken from the message.
+/* .IP usr_attr
+/* Attributes describing user rights and environment.
+/* .IP statusp
+/* Message delivery status. See below.
+/* DIAGNOSTICS
+/* Fatal errors: out of memory. Warnings: bad $HOME/.forward
+/* file type, permissions or ownership. The message delivery
+/* status is non-zero when delivery should be tried again.
+/* SEE ALSO
+/* include(3) include file processor.
+/* LICENSE
+/* .ad
+/* .fi
+/* The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/* Wietse Venema
+/* IBM T.J. Watson Research
+/* P.O. Box 704
+/* Yorktown Heights, NY 10598, USA
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <errno.h>
+#include <fcntl.h>
+#ifdef USE_PATHS_H
+#include <paths.h>
+#endif
+#include <string.h>
+
+/* Utility library. */
+
+#include <msg.h>
+#include <vstring.h>
+#include <vstream.h>
+#include <htable.h>
+#include <open_as.h>
+#include <lstat_as.h>
+#include <iostuff.h>
+#include <stringops.h>
+#include <mymalloc.h>
+#include <mac_expand.h>
+
+/* Global library. */
+
+#include <mypwd.h>
+#include <bounce.h>
+#include <defer.h>
+#include <been_here.h>
+#include <mail_params.h>
+#include <mail_conf.h>
+#include <ext_prop.h>
+#include <sent.h>
+#include <dsn_mask.h>
+#include <trace.h>
+
+/* Application-specific. */
+
+#include "local.h"
+
+#define NO 0
+#define YES 1
+
+/* deliver_dotforward - expand contents of .forward file */
+
+int deliver_dotforward(LOCAL_STATE state, USER_ATTR usr_attr, int *statusp)
+{
+ const char *myname = "deliver_dotforward";
+ struct stat st;
+ VSTRING *path;
+ struct mypasswd *mypwd;
+ int fd;
+ VSTREAM *fp;
+ int status;
+ int forward_found = NO;
+ int lookup_status;
+ int addr_count;
+ char *saved_forward_path;
+ char *lhs;
+ char *next;
+ int expand_status;
+ int saved_notify;
+
+ /*
+ * Make verbose logging easier to understand.
+ */
+ state.level++;
+ if (msg_verbose)
+ MSG_LOG_STATE(myname, state);
+
+ /*
+ * Skip this module if per-user forwarding is disabled.
+ */
+ if (*var_forward_path == 0)
+ return (NO);
+
+ /*
+ * Skip non-existing users. The mailbox delivery routine will catch the
+ * error.
+ */
+ if ((errno = mypwnam_err(state.msg_attr.user, &mypwd)) != 0) {
+ msg_warn("error looking up passwd info for %s: %m",
+ state.msg_attr.user);
+ dsb_simple(state.msg_attr.why, "4.0.0", "user lookup error");
+ *statusp = defer_append(BOUNCE_FLAGS(state.request),
+ BOUNCE_ATTR(state.msg_attr));
+ return (YES);
+ }
+ if (mypwd == 0)
+ return (NO);
+
+ /*
+ * From here on no early returns or we have a memory leak.
+ */
+
+ /*
+ * EXTERNAL LOOP CONTROL
+ *
+ * Set the delivered message attribute to the recipient, so that this
+ * message will list the correct forwarding address.
+ */
+ if (var_frozen_delivered == 0)
+ state.msg_attr.delivered = state.msg_attr.rcpt.address;
+
+ /*
+ * DELIVERY RIGHTS
+ *
+ * Do not inherit rights from the .forward file owner. Instead, use the
+ * recipient's rights, and insist that the .forward file is owned by the
+ * recipient. This is a small but significant difference. Use the
+ * recipient's rights for all /file and |command deliveries, and pass on
+ * these rights to command/file destinations in included files. When
+ * these are the rights of root, the /file and |command delivery routines
+ * will use unprivileged default rights instead. Better safe than sorry.
+ */
+ SET_USER_ATTR(usr_attr, mypwd, state.level);
+
+ /*
+ * DELIVERY POLICY
+ *
+ * Update the expansion type attribute so that we can decide if deliveries
+ * to |command and /file/name are allowed at all.
+ */
+ state.msg_attr.exp_type = EXPAND_TYPE_FWD;
+
+ /*
+ * WHERE TO REPORT DELIVERY PROBLEMS
+ *
+ * Set the owner attribute so that 1) include files won't set the sender to
+ * be this user and 2) mail forwarded to other local users will be
+ * resubmitted as a new queue file.
+ */
+ state.msg_attr.owner = state.msg_attr.user;
+
+ /*
+ * Search the forward_path for an existing forward file.
+ *
+ * If unmatched extensions should never be propagated, or if a forward file
+ * name includes the address extension, don't propagate the extension to
+ * the recipient addresses.
+ */
+ status = 0;
+ path = vstring_alloc(100);
+ saved_forward_path = mystrdup(var_forward_path);
+ next = saved_forward_path;
+ lookup_status = -1;
+
+ while ((lhs = mystrtok(&next, CHARS_COMMA_SP)) != 0) {
+ expand_status = local_expand(path, lhs, &state, &usr_attr,
+ var_fwd_exp_filter);
+ if ((expand_status & (MAC_PARSE_ERROR | MAC_PARSE_UNDEF)) == 0) {
+ lookup_status =
+ lstat_as(STR(path), &st, usr_attr.uid, usr_attr.gid);
+ if (msg_verbose)
+ msg_info("%s: path %s expand_status %d look_status %d", myname,
+ STR(path), expand_status, lookup_status);
+ if (lookup_status >= 0) {
+ if ((expand_status & LOCAL_EXP_EXTENSION_MATCHED) != 0
+ || (local_ext_prop_mask & EXT_PROP_FORWARD) == 0)
+ state.msg_attr.unmatched = 0;
+ break;
+ }
+ }
+ }
+
+ /*
+ * Process the forward file.
+ *
+ * Assume that usernames do not have file system meta characters. Open the
+ * .forward file as the user. Ignore files that aren't regular files,
+ * files that are owned by the wrong user, or files that have world write
+ * permission enabled.
+ *
+ * DUPLICATE/LOOP ELIMINATION
+ *
+ * If this user includes (an alias of) herself in her own .forward file,
+ * deliver to the user instead.
+ */
+ if (lookup_status >= 0) {
+
+ /*
+ * Don't expand a verify-only request.
+ */
+ if (state.request->flags & DEL_REQ_FLAG_MTA_VRFY) {
+ dsb_simple(state.msg_attr.why, "2.0.0",
+ "forward via file: %s", STR(path));
+ *statusp = sent(BOUNCE_FLAGS(state.request),
+ SENT_ATTR(state.msg_attr));
+ forward_found = YES;
+ } else if (been_here(state.dup_filter, "forward %s", STR(path)) == 0) {
+ state.msg_attr.exp_from = state.msg_attr.local;
+ if (S_ISREG(st.st_mode) == 0) {
+ msg_warn("file %s is not a regular file", STR(path));
+ } else if (st.st_uid != 0 && st.st_uid != usr_attr.uid) {
+ msg_warn("file %s has bad owner uid %ld",
+ STR(path), (long) st.st_uid);
+ } else if (st.st_mode & 002) {
+ msg_warn("file %s is world writable", STR(path));
+ } else if ((fd = open_as(STR(path), O_RDONLY, 0, usr_attr.uid, usr_attr.gid)) < 0) {
+ msg_warn("cannot open file %s: %m", STR(path));
+ } else {
+
+ /*
+ * XXX DSN. When delivering to an alias (i.e. the envelope
+ * sender address is not replaced) any ENVID, RET, or ORCPT
+ * parameters are propagated to all forwarding addresses
+ * associated with that alias. The NOTIFY parameter is
+ * propagated to the forwarding addresses, except that any
+ * SUCCESS keyword is removed.
+ */
+ close_on_exec(fd, CLOSE_ON_EXEC);
+ addr_count = 0;
+ fp = vstream_fdopen(fd, O_RDONLY);
+ saved_notify = state.msg_attr.rcpt.dsn_notify;
+ state.msg_attr.rcpt.dsn_notify =
+ (saved_notify == DSN_NOTIFY_SUCCESS ?
+ DSN_NOTIFY_NEVER : saved_notify & ~DSN_NOTIFY_SUCCESS);
+ status = deliver_token_stream(state, usr_attr, fp, &addr_count);
+ if (vstream_fclose(fp))
+ msg_warn("close file %s: %m", STR(path));
+ if (addr_count > 0) {
+ forward_found = YES;
+ been_here(state.dup_filter, "forward-done %s", STR(path));
+
+ /*
+ * XXX DSN. When delivering to an alias (i.e. the
+ * envelope sender address is not replaced) and the
+ * original NOTIFY parameter for the alias contained the
+ * SUCCESS keyword, an "expanded" DSN is issued for the
+ * alias.
+ */
+ if (status == 0 && (saved_notify & DSN_NOTIFY_SUCCESS)) {
+ state.msg_attr.rcpt.dsn_notify = saved_notify;
+ dsb_update(state.msg_attr.why, "2.0.0", "expanded",
+ DSB_SKIP_RMTA, DSB_SKIP_REPLY,
+ "alias expanded");
+ (void) trace_append(BOUNCE_FLAG_NONE,
+ SENT_ATTR(state.msg_attr));
+ }
+ }
+ }
+ } else if (been_here_check(state.dup_filter, "forward-done %s", STR(path)) != 0)
+ forward_found = YES; /* else we're recursive */
+ }
+
+ /*
+ * Clean up.
+ */
+ vstring_free(path);
+ myfree(saved_forward_path);
+ mypwfree(mypwd);
+
+ *statusp = status;
+ return (forward_found);
+}
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