-/* $Cambridge: exim/src/src/dbfn.c,v 1.2 2005/01/04 10:00:42 ph10 Exp $ */
-
/*************************************************
* Exim - an Internet mail transport agent *
*************************************************/
-/* Copyright (c) University of Cambridge 1995 - 2005 */
+/* Copyright (c) University of Cambridge 1995 - 2018 */
+/* Copyright (c) The Exim Maintainers 2020 */
/* See the file NOTICE for conditions of use and distribution. */
#include "exim.h"
+/* We have buffers holding path names for database files.
+PATH_MAX could be used here, but would be wasting memory, as we deal
+with database files like $spooldirectory/db/<name> */
+#define PATHLEN 256
+
/* Functions for accessing Exim's hints database, which consists of a number of
different DBM files. This module does not contain code for reading DBM files
/* For Berkeley DB >= 2, we can define a function to be called in case of DB
errors. This should help with debugging strange DB problems, e.g. getting "File
-exists" when you try to open a db file. */
+exists" when you try to open a db file. The API for this function was changed
+at DB release 4.3. */
#if defined(USE_DB) && defined(DB_VERSION_STRING)
void
+#if DB_VERSION_MAJOR > 4 || (DB_VERSION_MAJOR == 4 && DB_VERSION_MINOR >= 3)
+dbfn_bdb_error_callback(const DB_ENV *dbenv, const char *pfx, const char *msg)
+{
+dbenv = dbenv;
+#else
dbfn_bdb_error_callback(const char *pfx, char *msg)
{
+#endif
pfx = pfx;
log_write(0, LOG_MAIN, "Berkeley DB error: %s", msg);
}
dbblock Points to an open_db block to be filled in.
lof If TRUE, write to the log for actual open failures (locking failures
are always logged).
+ panic If TRUE, panic on failure to create the db directory
Returns: NULL if the open failed, or the locking failed. After locking
failures, errno is zero.
On success, dbblock is returned. This contains the dbm pointer and
the fd of the locked lock file.
+
+There are some calls that use O_RDWR|O_CREAT for the flags. Having discovered
+this in December 2005, I'm not sure if this is correct or not, but for the
+moment I haven't changed them.
*/
open_db *
-dbfn_open(uschar *name, int flags, open_db *dbblock, BOOL lof)
+dbfn_open(uschar *name, int flags, open_db *dbblock, BOOL lof, BOOL panic)
{
int rc, save_errno;
BOOL read_only = flags == O_RDONLY;
BOOL created = FALSE;
flock_t lock_data;
-uschar buffer[256];
+uschar dirname[PATHLEN], filename[PATHLEN];
+
+DEBUG(D_hints_lookup) acl_level++;
/* The first thing to do is to open a separate file on which to lock. This
ensures that Exim has exclusive use of the database before it even tries to
unnecessarily, because usually the lock file will be there. If the directory
exists, there is no error. */
-sprintf(CS buffer, "%s/db/%s.lockfile", spool_directory, name);
+snprintf(CS dirname, sizeof(dirname), "%s/db", spool_directory);
+snprintf(CS filename, sizeof(filename), "%s/%s.lockfile", dirname, name);
-if ((dbblock->lockfd = Uopen(buffer, O_RDWR, EXIMDB_LOCKFILE_MODE)) < 0)
+if ((dbblock->lockfd = Uopen(filename, O_RDWR, EXIMDB_LOCKFILE_MODE)) < 0)
{
created = TRUE;
- (void)directory_make(spool_directory, US"db", EXIMDB_DIRECTORY_MODE, TRUE);
- dbblock->lockfd = Uopen(buffer, O_RDWR|O_CREAT, EXIMDB_LOCKFILE_MODE);
+ (void)directory_make(spool_directory, US"db", EXIMDB_DIRECTORY_MODE, panic);
+ dbblock->lockfd = Uopen(filename, O_RDWR|O_CREAT, EXIMDB_LOCKFILE_MODE);
}
if (dbblock->lockfd < 0)
{
log_write(0, LOG_MAIN, "%s",
- string_open_failed(errno, "database lock file %s", buffer));
+ string_open_failed("database lock file %s", filename));
errno = 0; /* Indicates locking failure */
+ DEBUG(D_hints_lookup) acl_level--;
return NULL;
}
lock_data.l_whence = lock_data.l_start = lock_data.l_len = 0;
DEBUG(D_hints_lookup|D_retry|D_route|D_deliver)
- debug_printf("locking %s\n", buffer);
+ debug_printf_indent("locking %s\n", filename);
sigalrm_seen = FALSE;
-alarm(EXIMDB_LOCK_TIMEOUT);
+ALARM(EXIMDB_LOCK_TIMEOUT);
rc = fcntl(dbblock->lockfd, F_SETLKW, &lock_data);
-alarm(0);
+ALARM_CLR(0);
if (sigalrm_seen) errno = ETIMEDOUT;
if (rc < 0)
{
- log_write(0, LOG_MAIN, "Failed to get %s lock for %s: %s",
- ((flags & O_RDONLY) != 0)? "read" : "write", buffer,
- (errno == ETIMEDOUT)? "timed out" : strerror(errno));
- close(dbblock->lockfd);
+ log_write(0, LOG_MAIN|LOG_PANIC, "Failed to get %s lock for %s: %s",
+ read_only ? "read" : "write", filename,
+ errno == ETIMEDOUT ? "timed out" : strerror(errno));
+ (void)close(dbblock->lockfd);
errno = 0; /* Indicates locking failure */
+ DEBUG(D_hints_lookup) acl_level--;
return NULL;
}
-DEBUG(D_hints_lookup) debug_printf("locked %s\n", buffer);
+DEBUG(D_hints_lookup) debug_printf_indent("locked %s\n", filename);
/* At this point we have an opened and locked separate lock file, that is,
exclusive access to the database, so we can go ahead and open it. If we are
expected to create it, don't do so at first, again so that we can detect
whether we need to change its ownership (see comments about the lock file
-above.) */
+above.) There have been regular reports of crashes while opening hints
+databases - often this is caused by non-matching db.h and the library. To make
+it easy to pin this down, there are now debug statements on either side of the
+open call. */
-sprintf(CS buffer, "%s/db/%s", spool_directory, name);
-EXIM_DBOPEN(buffer, flags, EXIMDB_MODE, &(dbblock->dbptr));
+snprintf(CS filename, sizeof(filename), "%s/%s", dirname, name);
+EXIM_DBOPEN(filename, dirname, flags, EXIMDB_MODE, &(dbblock->dbptr));
-if (dbblock->dbptr == NULL && errno == ENOENT && flags == O_RDWR)
+if (!dbblock->dbptr && errno == ENOENT && flags == O_RDWR)
{
DEBUG(D_hints_lookup)
- debug_printf("%s appears not to exist: trying to create\n", buffer);
+ debug_printf_indent("%s appears not to exist: trying to create\n", filename);
created = TRUE;
- EXIM_DBOPEN(buffer, flags|O_CREAT, EXIMDB_MODE, &(dbblock->dbptr));
+ EXIM_DBOPEN(filename, dirname, flags|O_CREAT, EXIMDB_MODE, &(dbblock->dbptr));
}
save_errno = errno;
if (created && geteuid() == root_uid)
{
- DIR *dd;
- struct dirent *ent;
- uschar *lastname = Ustrrchr(buffer, '/') + 1;
+ DIR * dd;
+ uschar path[PATHLEN];
+ uschar *lastname;
int namelen = Ustrlen(name);
+ Ustrcpy(path, filename);
+ lastname = Ustrrchr(path, '/') + 1;
*lastname = 0;
- dd = opendir(CS buffer);
- while ((ent = readdir(dd)) != NULL)
- {
- if (Ustrncmp(ent->d_name, name, namelen) == 0)
- {
- struct stat statbuf;
- Ustrcpy(lastname, ent->d_name);
- if (Ustat(buffer, &statbuf) >= 0 && statbuf.st_uid != exim_uid)
- {
- DEBUG(D_hints_lookup) debug_printf("ensuring %s is owned by exim\n", buffer);
- Uchown(buffer, exim_uid, exim_gid);
- }
- }
- }
+ if ((dd = exim_opendir(path)))
+ for (struct dirent *ent; ent = readdir(dd); )
+ if (Ustrncmp(ent->d_name, name, namelen) == 0)
+ {
+ struct stat statbuf;
+ /* Filenames from readdir() are trusted,
+ so use a taint-nonchecking copy */
+ strcpy(CS lastname, CCS ent->d_name);
+ if (Ustat(path, &statbuf) >= 0 && statbuf.st_uid != exim_uid)
+ {
+ DEBUG(D_hints_lookup)
+ debug_printf_indent("ensuring %s is owned by exim\n", path);
+ if (exim_chown(path, exim_uid, exim_gid))
+ DEBUG(D_hints_lookup)
+ debug_printf_indent("failed setting %s to owned by exim\n", path);
+ }
+ }
closedir(dd);
}
/* If the open has failed, return NULL, leaving errno set. If lof is TRUE,
-log the event - also for debugging - but not if the file just doesn't exist. */
+log the event - also for debugging - but debug only if the file just doesn't
+exist. */
-if (dbblock->dbptr == NULL)
+if (!dbblock->dbptr)
{
- if (save_errno != ENOENT)
- {
- if (lof)
- log_write(0, LOG_MAIN, "%s", string_open_failed(save_errno, "DB file %s",
- buffer));
- else
- DEBUG(D_hints_lookup)
- debug_printf("%s", CS string_open_failed(save_errno, "DB file %s\n",
- buffer));
- }
- close(dbblock->lockfd);
errno = save_errno;
+ if (lof && save_errno != ENOENT)
+ log_write(0, LOG_MAIN, "%s", string_open_failed("DB file %s",
+ filename));
+ else
+ DEBUG(D_hints_lookup)
+ debug_printf_indent("%s\n", CS string_open_failed("DB file %s",
+ filename));
+ (void)close(dbblock->lockfd);
+ errno = save_errno;
+ DEBUG(D_hints_lookup) acl_level--;
return NULL;
}
DEBUG(D_hints_lookup)
- debug_printf("opened hints database %s: flags=%x\n", buffer, flags);
+ debug_printf_indent("opened hints database %s: flags=%s\n", filename,
+ flags == O_RDONLY ? "O_RDONLY"
+ : flags == O_RDWR ? "O_RDWR"
+ : flags == (O_RDWR|O_CREAT) ? "O_RDWR|O_CREAT"
+ : "??");
/* Pass back the block containing the opened database handle and the open fd
for the lock. */
dbfn_close(open_db *dbblock)
{
EXIM_DBCLOSE(dbblock->dbptr);
-close(dbblock->lockfd);
+(void)close(dbblock->lockfd);
+DEBUG(D_hints_lookup)
+ { debug_printf_indent("closed hints database and lockfile\n"); acl_level--; }
}
*/
void *
-dbfn_read_with_length(open_db *dbblock, uschar *key, int *length)
+dbfn_read_with_length(open_db *dbblock, const uschar *key, int *length)
{
void *yield;
EXIM_DATUM key_datum, result_datum;
+int klen = Ustrlen(key) + 1;
+uschar * key_copy = store_get(klen, is_tainted(key));
+
+memcpy(key_copy, key, klen);
-DEBUG(D_hints_lookup) debug_printf("dbfn_read: key=%s\n", key);
+DEBUG(D_hints_lookup) debug_printf_indent("dbfn_read: key=%s\n", key);
EXIM_DATUM_INIT(key_datum); /* Some DBM libraries require the datum */
EXIM_DATUM_INIT(result_datum); /* to be cleared before use. */
-EXIM_DATUM_DATA(key_datum) = CS key;
-EXIM_DATUM_SIZE(key_datum) = Ustrlen(key) + 1;
+EXIM_DATUM_DATA(key_datum) = CS key_copy;
+EXIM_DATUM_SIZE(key_datum) = klen;
if (!EXIM_DBGET(dbblock->dbptr, key_datum, result_datum)) return NULL;
-yield = store_get(EXIM_DATUM_SIZE(result_datum));
+/* Assume the data store could have been tainted. Properly, we should
+store the taint status with the data. */
+
+yield = store_get(EXIM_DATUM_SIZE(result_datum), TRUE);
memcpy(yield, EXIM_DATUM_DATA(result_datum), EXIM_DATUM_SIZE(result_datum));
if (length != NULL) *length = EXIM_DATUM_SIZE(result_datum);
}
+/* Read a record. If the length is not as expected then delete it, write
+an error log line, delete the record and return NULL.
+Use this for fixed-size records (so not retry or wait records).
+
+Arguments:
+ dbblock a pointer to an open database block
+ key the key of the record to be read
+ length the expected record length
+
+Returns: a pointer to the retrieved record, or
+ NULL if the record is not found/bad
+*/
+
+void *
+dbfn_read_enforce_length(open_db * dbblock, const uschar * key, size_t length)
+{
+int rlen;
+void * yield = dbfn_read_with_length(dbblock, key, &rlen);
+
+if (yield)
+ {
+ if (rlen == length) return yield;
+ log_write(0, LOG_MAIN|LOG_PANIC, "Bad db record size for '%s'", key);
+ dbfn_delete(dbblock, key);
+ }
+return NULL;
+}
+
/*************************************************
* Write to database file *
*/
int
-dbfn_write(open_db *dbblock, uschar *key, void *ptr, int length)
+dbfn_write(open_db *dbblock, const uschar *key, void *ptr, int length)
{
EXIM_DATUM key_datum, value_datum;
dbdata_generic *gptr = (dbdata_generic *)ptr;
+int klen = Ustrlen(key) + 1;
+uschar * key_copy = store_get(klen, is_tainted(key));
+
+memcpy(key_copy, key, klen);
gptr->time_stamp = time(NULL);
-DEBUG(D_hints_lookup) debug_printf("dbfn_write: key=%s\n", key);
+DEBUG(D_hints_lookup) debug_printf_indent("dbfn_write: key=%s\n", key);
EXIM_DATUM_INIT(key_datum); /* Some DBM libraries require the datum */
EXIM_DATUM_INIT(value_datum); /* to be cleared before use. */
-EXIM_DATUM_DATA(key_datum) = CS key;
-EXIM_DATUM_SIZE(key_datum) = Ustrlen(key) + 1;
+EXIM_DATUM_DATA(key_datum) = CS key_copy;
+EXIM_DATUM_SIZE(key_datum) = klen;
EXIM_DATUM_DATA(value_datum) = CS ptr;
EXIM_DATUM_SIZE(value_datum) = length;
return EXIM_DBPUT(dbblock->dbptr, key_datum, value_datum);
*/
int
-dbfn_delete(open_db *dbblock, uschar *key)
+dbfn_delete(open_db *dbblock, const uschar *key)
{
+int klen = Ustrlen(key) + 1;
+uschar * key_copy = store_get(klen, is_tainted(key));
+
+DEBUG(D_hints_lookup) debug_printf_indent("dbfn_delete: key=%s\n", key);
+
+memcpy(key_copy, key, klen);
EXIM_DATUM key_datum;
EXIM_DATUM_INIT(key_datum); /* Some DBM libraries require clearing */
-EXIM_DATUM_DATA(key_datum) = CS key;
-EXIM_DATUM_SIZE(key_datum) = Ustrlen(key) + 1;
+EXIM_DATUM_DATA(key_datum) = CS key_copy;
+EXIM_DATUM_SIZE(key_datum) = klen;
return EXIM_DBDEL(dbblock->dbptr, key_datum);
}
{
EXIM_DATUM key_datum, value_datum;
uschar *yield;
-value_datum = value_datum; /* dummy; not all db libraries use this */
+
+DEBUG(D_hints_lookup) debug_printf_indent("dbfn_scan\n");
/* Some dbm require an initialization */
}
start = clock();
- odb = dbfn_open(s, O_RDWR, dbblock + i, TRUE);
+ odb = dbfn_open(s, O_RDWR, dbblock + i, TRUE, TRUE);
stop = clock();
- if (odb != NULL)
+ if (odb)
{
current = i;
printf("opened %d\n", current);
git://git.exim.org / exim.git / blobdiff