*************************************************/
/* Copyright (c) University of Cambridge 1995 - 2018 */
+/* Copyright (c) The Exim Maintainers 2020 - 2021 */
/* See the file NOTICE for conditions of use and distribution. */
/* Functions for writing log files. The code for maintaining datestamped
US"Negotiation failed for proxy configured host",
US"Authenticator 'other' failure",
US"target not supporting SMTPUTF8",
- US"",
+ US"host is local",
+ US"tainted filename",
US"Not time for routing",
US"Not time for local delivery",
Returns: a file descriptor, or < 0 on failure (errno set)
*/
-int
-log_create(uschar *name)
+static int
+log_open_already_exim(uschar * const name)
{
-int fd = Uopen(name,
-#ifdef O_CLOEXEC
- O_CLOEXEC |
-#endif
- O_CREAT|O_APPEND|O_WRONLY, LOG_MODE);
+int fd = -1;
+const int flags = O_WRONLY | O_APPEND | O_CREAT | O_NONBLOCK;
+
+if (geteuid() != exim_uid)
+ {
+ errno = EACCES;
+ return -1;
+ }
+
+fd = Uopen(name, flags, LOG_MODE);
/* If creation failed, attempt to build a log directory in case that is the
problem. */
uschar *lastslash = Ustrrchr(name, '/');
*lastslash = 0;
created = directory_make(NULL, name, LOG_DIRECTORY_MODE, FALSE);
- DEBUG(D_any) debug_printf("%s log directory %s\n",
- created ? "created" : "failed to create", name);
+ DEBUG(D_any)
+ if (created)
+ debug_printf("created log directory %s\n", name);
+ else
+ debug_printf("failed to create log directory %s: %s\n", name, strerror(errno));
*lastslash = '/';
- if (created) fd = Uopen(name,
-#ifdef O_CLOEXEC
- O_CLOEXEC |
-#endif
- O_CREAT|O_APPEND|O_WRONLY, LOG_MODE);
+ if (created) fd = Uopen(name, flags, LOG_MODE);
}
return fd;
+/* Inspired by OpenSSH's mm_send_fd(). Thanks!
+Send fd over socketpair.
+Return: true iff good.
+*/
+
+static BOOL
+log_send_fd(const int sock, const int fd)
+{
+struct msghdr msg;
+union {
+ struct cmsghdr hdr;
+ char buf[CMSG_SPACE(sizeof(int))];
+} cmsgbuf;
+struct cmsghdr *cmsg;
+char ch = 'A';
+struct iovec vec = {.iov_base = &ch, .iov_len = 1};
+ssize_t n;
+
+memset(&msg, 0, sizeof(msg));
+memset(&cmsgbuf, 0, sizeof(cmsgbuf));
+msg.msg_control = &cmsgbuf.buf;
+msg.msg_controllen = sizeof(cmsgbuf.buf);
+
+cmsg = CMSG_FIRSTHDR(&msg);
+cmsg->cmsg_len = CMSG_LEN(sizeof(int));
+cmsg->cmsg_level = SOL_SOCKET;
+cmsg->cmsg_type = SCM_RIGHTS;
+*(int *)CMSG_DATA(cmsg) = fd;
+
+msg.msg_iov = &vec;
+msg.msg_iovlen = 1;
+
+while ((n = sendmsg(sock, &msg, 0)) == -1 && errno == EINTR);
+return n == 1;
+}
+
+/* Inspired by OpenSSH's mm_receive_fd(). Thanks!
+Return fd passed over socketpair, or -1 on error.
+*/
+
+static int
+log_recv_fd(const int sock)
+{
+struct msghdr msg;
+union {
+ struct cmsghdr hdr;
+ char buf[CMSG_SPACE(sizeof(int))];
+} cmsgbuf;
+struct cmsghdr *cmsg;
+char ch = '\0';
+struct iovec vec = {.iov_base = &ch, .iov_len = 1};
+ssize_t n;
+int fd;
+
+memset(&msg, 0, sizeof(msg));
+msg.msg_iov = &vec;
+msg.msg_iovlen = 1;
+
+memset(&cmsgbuf, 0, sizeof(cmsgbuf));
+msg.msg_control = &cmsgbuf.buf;
+msg.msg_controllen = sizeof(cmsgbuf.buf);
+
+while ((n = recvmsg(sock, &msg, 0)) == -1 && errno == EINTR) ;
+if (n != 1 || ch != 'A') return -1;
+
+if (!(cmsg = CMSG_FIRSTHDR(&msg))) return -1;
+if (cmsg->cmsg_type != SCM_RIGHTS) return -1;
+if ((fd = *(const int *)CMSG_DATA(cmsg)) < 0) return -1;
+return fd;
+}
+
+
+
/*************************************************
* Create a log file as the exim user *
*************************************************/
*/
int
-log_create_as_exim(uschar *name)
+log_open_as_exim(uschar * const name)
{
-pid_t pid = exim_fork(US"logfile-create");
-int status = 1;
int fd = -1;
+const uid_t euid = geteuid();
-/* In the subprocess, change uid/gid and do the creation. Return 0 from the
-subprocess on success. If we don't check for setuid failures, then the file
-can be created as root, so vulnerabilities which cause setuid to fail mean
-that the Exim user can use symlinks to cause a file to be opened/created as
-root. We always open for append, so can't nuke existing content but it would
-still be Rather Bad. */
-
-if (pid == 0)
+if (euid == exim_uid)
+ fd = log_open_already_exim(name);
+else if (euid == root_uid)
{
- if (setgid(exim_gid) < 0)
- die(US"exim: setgid for log-file creation failed, aborting",
- US"Unexpected log failure, please try later");
- if (setuid(exim_uid) < 0)
- die(US"exim: setuid for log-file creation failed, aborting",
- US"Unexpected log failure, please try later");
- _exit((log_create(name) < 0)? 1 : 0);
- }
-
-/* If we created a subprocess, wait for it. If it succeeded, try the open. */
+ int sock[2];
+ if (socketpair(AF_UNIX, SOCK_STREAM, 0, sock) == 0)
+ {
+ const pid_t pid = fork();
+ if (pid == 0)
+ {
+ (void)close(sock[0]);
+ if ( setgroups(1, &exim_gid) != 0
+ || setgid(exim_gid) != 0
+ || setuid(exim_uid) != 0
+
+ || getuid() != exim_uid || geteuid() != exim_uid
+ || getgid() != exim_gid || getegid() != exim_gid
+
+ || (fd = log_open_already_exim(name)) < 0
+ || !log_send_fd(sock[1], fd)
+ ) _exit(EXIT_FAILURE);
+ (void)close(sock[1]);
+ _exit(EXIT_SUCCESS);
+ }
-while (pid > 0 && waitpid(pid, &status, 0) != pid);
-if (status == 0) fd = Uopen(name,
-#ifdef O_CLOEXEC
- O_CLOEXEC |
-#endif
- O_APPEND|O_WRONLY, LOG_MODE);
+ (void)close(sock[1]);
+ if (pid > 0)
+ {
+ fd = log_recv_fd(sock[0]);
+ while (waitpid(pid, NULL, 0) == -1 && errno == EINTR);
+ }
+ (void)close(sock[0]);
+ }
+ }
-/* If we failed to create a subprocess, we are in a bad way. We return
-with fd still < 0, and errno set, letting the caller handle the error. */
+if (fd >= 0)
+ {
+ int flags;
+ flags = fcntl(fd, F_GETFD);
+ if (flags != -1) (void)fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
+ flags = fcntl(fd, F_GETFL);
+ if (flags != -1) (void)fcntl(fd, F_SETFL, flags & ~O_NONBLOCK);
+ }
+else
+ errno = EACCES;
return fd;
}
it does not exist. This may be called recursively on failure, in order to open
the panic log.
-The directory is in the static variable file_path. This is static so that it
+The directory is in the static variable file_path. This is static so that
the work of sorting out the path is done just once per Exim process.
Exim is normally configured to avoid running as root wherever possible, the log
ok = string_format(buffer, sizeof(buffer), CS file_path, log_names[type]);
-/* Save the name of the mainlog for rollover processing. Without a datestamp,
-it gets statted to see if it has been cycled. With a datestamp, the datestamp
-will be compared. The static slot for saving it is the same size as buffer,
-and the text has been checked above to fit, so this use of strcpy() is OK. */
-
-if (type == lt_main && string_datestamp_offset >= 0)
+switch (type)
{
- Ustrcpy(mainlog_name, buffer);
- mainlog_datestamp = mainlog_name + string_datestamp_offset;
- }
+ case lt_main:
+ /* Save the name of the mainlog for rollover processing. Without a datestamp,
+ it gets statted to see if it has been cycled. With a datestamp, the datestamp
+ will be compared. The static slot for saving it is the same size as buffer,
+ and the text has been checked above to fit, so this use of strcpy() is OK. */
+
+ Ustrcpy(mainlog_name, buffer);
+ if (string_datestamp_offset > 0)
+ mainlog_datestamp = mainlog_name + string_datestamp_offset;
+ break;
-/* Ditto for the reject log */
+ case lt_reject:
+ /* Ditto for the reject log */
-else if (type == lt_reject && string_datestamp_offset >= 0)
- {
- Ustrcpy(rejectlog_name, buffer);
- rejectlog_datestamp = rejectlog_name + string_datestamp_offset;
- }
+ Ustrcpy(rejectlog_name, buffer);
+ if (string_datestamp_offset > 0)
+ rejectlog_datestamp = rejectlog_name + string_datestamp_offset;
+ break;
-/* and deal with the debug log (which keeps the datestamp, but does not
-update it) */
+ case lt_debug:
+ /* and deal with the debug log (which keeps the datestamp, but does not
+ update it) */
-else if (type == lt_debug)
- {
- Ustrcpy(debuglog_name, buffer);
- if (tag)
- {
- /* this won't change the offset of the datestamp */
- ok2 = string_format(buffer, sizeof(buffer), "%s%s",
- debuglog_name, tag);
- if (ok2)
- Ustrcpy(debuglog_name, buffer);
- }
- }
+ Ustrcpy(debuglog_name, buffer);
+ if (tag)
+ {
+ if (is_tainted(tag))
+ die(US"exim: tainted tag for debug log filename",
+ US"Logging failure; please try later");
+
+ /* this won't change the offset of the datestamp */
+ ok2 = string_format(buffer, sizeof(buffer), "%s%s",
+ debuglog_name, tag);
+ if (ok2)
+ Ustrcpy(debuglog_name, buffer);
+ }
+ break;
-/* Remove any datestamp if this is the panic log. This is rare, so there's no
-need to optimize getting the datestamp length. We remove one non-alphanumeric
-char afterwards if at the start, otherwise one before. */
+ default:
+ /* Remove any datestamp if this is the panic log. This is rare, so there's no
+ need to optimize getting the datestamp length. We remove one non-alphanumeric
+ char afterwards if at the start, otherwise one before. */
-else if (string_datestamp_offset >= 0)
- {
- uschar * from = buffer + string_datestamp_offset;
- uschar * to = from + string_datestamp_length;
+ if (string_datestamp_offset >= 0)
+ {
+ uschar * from = buffer + string_datestamp_offset;
+ uschar * to = from + string_datestamp_length;
- if (from == buffer || from[-1] == '/')
- {
- if (!isalnum(*to)) to++;
- }
- else
- if (!isalnum(from[-1])) from--;
+ if (from == buffer || from[-1] == '/')
+ {
+ if (!isalnum(*to)) to++;
+ }
+ else
+ if (!isalnum(from[-1])) from--;
- /* This copy is ok, because we know that to is a substring of from. But
- due to overlap we must use memmove() not Ustrcpy(). */
- memmove(from, to, Ustrlen(to)+1);
+ /* This copy is ok, because we know that to is a substring of from. But
+ due to overlap we must use memmove() not Ustrcpy(). */
+ memmove(from, to, Ustrlen(to)+1);
+ }
+ break;
}
/* If the file name is too long, it is an unrecoverable disaster */
die(US"exim: log file path too long: aborting",
US"Logging failure; please try later");
-/* We now have the file name. Try to open an existing file. After a successful
-open, arrange for automatic closure on exec(), and then return. */
-
-*fd = Uopen(buffer,
-#ifdef O_CLOEXEC
- O_CLOEXEC |
-#endif
- O_APPEND|O_WRONLY, LOG_MODE);
+/* We now have the file name. After a successful open, return. */
-if (*fd >= 0)
- {
-#ifndef O_CLOEXEC
- (void)fcntl(*fd, F_SETFD, fcntl(*fd, F_GETFD) | FD_CLOEXEC);
-#endif
+if ((*fd = log_open_as_exim(buffer)) >= 0)
return;
- }
-
-/* Open was not successful: try creating the file. If this is a root process,
-we must do the creating in a subprocess set to exim:exim in order to ensure
-that the file is created with the right ownership. Otherwise, there can be a
-race if another Exim process is trying to write to the log at the same time.
-The use of SIGUSR1 by the exiwhat utility can provoke a lot of simultaneous
-writing. */
euid = geteuid();
-/* If we are already running as the Exim user (even if that user is root),
-we can go ahead and create in the current process. */
-
-if (euid == exim_uid) *fd = log_create(buffer);
-
-/* Otherwise, if we are root, do the creation in an exim:exim subprocess. If we
-are neither exim nor root, creation is not attempted. */
-
-else if (euid == root_uid) *fd = log_create_as_exim(buffer);
-
-/* If we now have an open file, set the close-on-exec flag and return. */
-
-if (*fd >= 0)
- {
-#ifndef O_CLOEXEC
- (void)fcntl(*fd, F_SETFD, fcntl(*fd, F_GETFD) | FD_CLOEXEC);
-#endif
- return;
- }
-
/* Creation failed. There are some circumstances in which we get here when
the effective uid is not root or exim, which is the problem. (For example, a
non-setuid binary with log_arguments set, called in certain ways.) Rather than
}
+/* Pull the file out of the configured or the compiled-in list.
+Called for an empty log_file_path element, for debug logging activation
+when file_path has not previously been set, and from the appenfile transport setup. */
-static void
-set_file_path(void)
+void
+set_file_path(BOOL *multiple)
{
+uschar *s;
int sep = ':'; /* Fixed separator - outside use */
-uschar *t;
-const uschar *tt = US LOG_FILE_PATH;
-while ((t = string_nextinlist(&tt, &sep, log_buffer, LOG_BUFFER_SIZE)))
- {
- if (Ustrcmp(t, "syslog") == 0 || t[0] == 0) continue;
- file_path = string_copy(t);
- break;
- }
+const uschar *ss = *log_file_path ? log_file_path : US LOG_FILE_PATH;
+
+if (*ss)
+ for (logging_mode = 0;
+ s = string_nextinlist(&ss, &sep, log_buffer, LOG_BUFFER_SIZE); )
+ {
+ if (Ustrcmp(s, "syslog") == 0)
+ logging_mode |= LOG_MODE_SYSLOG;
+ else if (!(logging_mode & LOG_MODE_FILE)) /* no file yet */
+ {
+ logging_mode |= LOG_MODE_FILE;
+ if (*s) file_path = string_copy(s); /* If a non-empty path is given, use it */
+ }
+ else if (multiple) *multiple = TRUE;
+ }
+else
+ logging_mode = LOG_MODE_FILE;
+
+/* Set up the ultimate default if necessary. */
+
+if (logging_mode & LOG_MODE_FILE && !*file_path)
+ if (LOG_FILE_PATH[0])
+ {
+ /* If we still do not have a file_path, we take
+ the first non-empty, non-syslog item in LOG_FILE_PATH, if there is
+ one. If there is no such item, use the ultimate default in the
+ spool directory. */
+
+ for (ss = US LOG_FILE_PATH;
+ s = string_nextinlist(&ss, &sep, log_buffer, LOG_BUFFER_SIZE);)
+ {
+ if (*s != '/') continue;
+ file_path = string_copy(s);
+ }
+ }
+ else file_path = string_sprintf("%s/log/%%slog", spool_directory);
}
void
mainlog_close(void)
{
-if (mainlogfd < 0) return;
+/* avoid closing it if it is closed already or if we do not see a chance
+to open the file mainlog later again */
+if (mainlogfd < 0 /* already closed */
+ || !(geteuid() == 0 || geteuid() == exim_uid))
+ return;
(void)close(mainlogfd);
mainlogfd = -1;
mainlog_inode = 0;
store_pool = POOL_PERM;
- /* If nothing has been set, don't waste effort... the default values for the
- statics are file_path="" and logging_mode = LOG_MODE_FILE. */
-
- if (*log_file_path)
- {
- int sep = ':'; /* Fixed separator - outside use */
- uschar *s;
- const uschar *ss = log_file_path;
-
- logging_mode = 0;
- while ((s = string_nextinlist(&ss, &sep, log_buffer, LOG_BUFFER_SIZE)))
- {
- if (Ustrcmp(s, "syslog") == 0)
- logging_mode |= LOG_MODE_SYSLOG;
- else if (logging_mode & LOG_MODE_FILE)
- multiple = TRUE;
- else
- {
- logging_mode |= LOG_MODE_FILE;
-
- /* If a non-empty path is given, use it */
-
- if (*s)
- file_path = string_copy(s);
-
- /* If the path is empty, we want to use the first non-empty, non-
- syslog item in LOG_FILE_PATH, if there is one, since the value of
- log_file_path may have been set at runtime. If there is no such item,
- use the ultimate default in the spool directory. */
-
- else
- set_file_path(); /* Empty item in log_file_path */
- } /* First non-syslog item in log_file_path */
- } /* Scan of log_file_path */
- }
+ /* make sure that we have a valid log file path in "file_path",
+ the open_log() later relies on it */
+ set_file_path(&multiple);
/* If no modes have been selected, it is a major disaster */
die(US"Neither syslog nor file logging set in log_file_path",
US"Unexpected logging failure");
- /* Set up the ultimate default if necessary. Then revert to the old store
- pool, and record that we've sorted out the path. */
+ /* Revert to the old store pool, and record that we've sorted out the path. */
- if (logging_mode & LOG_MODE_FILE && !file_path[0])
- file_path = string_sprintf("%s/log/%%slog", spool_directory);
store_pool = old_pool;
path_inspected = TRUE;
if (f.disable_logging)
{
DEBUG(D_any) debug_printf("log writing disabled\n");
+ if ((flags & LOG_PANIC_DIE) == LOG_PANIC_DIE) exim_exit(EXIT_FAILURE);
return;
}
if (logging_mode & LOG_MODE_FILE)
{
+ if (!*file_path) set_file_path(NULL);
panic_recurseflag = TRUE;
open_log(&paniclogfd, lt_panic, NULL); /* Won't return on failure */
panic_recurseflag = FALSE;
if (panic_save_buffer)
- {
- int i = write(paniclogfd, panic_save_buffer, Ustrlen(panic_save_buffer));
- i = i; /* compiler quietening */
- }
+ (void) write(paniclogfd, panic_save_buffer, Ustrlen(panic_save_buffer));
written_len = write_to_fd_buf(paniclogfd, g->s, g->ptr);
if (written_len != g->ptr)
uschar *string, bit_table *options, int count, uschar *which, int flags)
{
uschar *errmsg;
-if (string == NULL) return;
+if (!string) return;
if (*string == '=')
{
char *end; /* Not uschar */
memset(selector, 0, sizeof(*selector)*selsize);
*selector = strtoul(CS string+1, &end, 0);
- if (*end == 0) return;
+ if (!*end) return;
errmsg = string_sprintf("malformed numeric %s_selector setting: %s", which,
string);
goto ERROR_RETURN;
int len;
bit_table *start, *end;
- while (isspace(*string)) string++;
- if (*string == 0) return;
+ Uskip_whitespace(&string);
+ if (!*string) return;
if (*string != '+' && *string != '-')
{
bit_table *middle = start + (end - start)/2;
int c = Ustrncmp(s, middle->name, len);
if (c == 0)
- {
if (middle->name[len] != 0) c = -1; else
{
unsigned int bit = middle->bit;
break; /* Out of loop to match selector name */
}
- }
if (c < 0) end = middle; else start = middle + 1;
} /* Loop to match selector name */
resulting in certain setup not having been done. Hack this for now so we
do not segfault; note that nondefault log locations will not work */
-if (!*file_path) set_file_path();
+if (!*file_path) set_file_path(NULL);
open_log(&fd, lt_debug, tag_name);
unlink_log(lt_debug);
}
+/* Called from the appendfile transport setup. */
+void
+open_logs(void)
+{
+set_file_path(NULL);
+if (!(logging_mode & LOG_MODE_FILE)) return;
+open_log(&mainlogfd, lt_main, 0);
+open_log(&rejectlogfd, lt_reject, 0);
+}
/* End of log.c */
git://git.exim.org / exim.git / blobdiff