X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/b10c87b38c2345d15d30da5c18c823355ac506a9..995e599afd3e6468d3396fb351ed0cd0ea212779:/src/src/dbfn.c diff --git a/src/src/dbfn.c b/src/src/dbfn.c index a60775681..be6a47afc 100644 --- a/src/src/dbfn.c +++ b/src/src/dbfn.c @@ -3,11 +3,17 @@ *************************************************/ /* 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/ */ +#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 @@ -92,7 +98,7 @@ int rc, save_errno; BOOL read_only = flags == O_RDONLY; BOOL created = FALSE; flock_t lock_data; -uschar dirname[256], filename[256]; +uschar dirname[PATHLEN], filename[PATHLEN]; DEBUG(D_hints_lookup) acl_level++; @@ -122,7 +128,7 @@ if ((dbblock->lockfd = Uopen(filename, O_RDWR, EXIMDB_LOCKFILE_MODE)) < 0) if (dbblock->lockfd < 0) { log_write(0, LOG_MAIN, "%s", - string_open_failed(errno, "database lock file %s", filename)); + string_open_failed("database lock file %s", filename)); errno = 0; /* Indicates locking failure */ DEBUG(D_hints_lookup) acl_level--; return NULL; @@ -194,26 +200,32 @@ but creation of the database file failed. */ if (created && geteuid() == root_uid) { - DIR *dd; - struct dirent *ent; - uschar *lastname = Ustrrchr(filename, '/') + 1; + DIR * dd; + uschar path[PATHLEN]; + uschar *lastname; int namelen = Ustrlen(name); + Ustrcpy(path, filename); + lastname = Ustrrchr(path, '/') + 1; *lastname = 0; - dd = opendir(CS filename); - while ((ent = readdir(dd))) - if (Ustrncmp(ent->d_name, name, namelen) == 0) - { - struct stat statbuf; - Ustrcpy(lastname, ent->d_name); - if (Ustat(filename, &statbuf) >= 0 && statbuf.st_uid != exim_uid) - { - DEBUG(D_hints_lookup) debug_printf_indent("ensuring %s is owned by exim\n", filename); - if (exim_chown(filename, exim_uid, exim_gid)) - DEBUG(D_hints_lookup) debug_printf_indent("failed setting %s to owned by exim\n", filename); - } - } + 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); } @@ -224,12 +236,13 @@ exist. */ if (!dbblock->dbptr) { + errno = save_errno; if (lof && save_errno != ENOENT) - log_write(0, LOG_MAIN, "%s", string_open_failed(save_errno, "DB file %s", + 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(save_errno, "DB file %s", + debug_printf_indent("%s\n", CS string_open_failed("DB file %s", filename)); (void)close(dbblock->lockfd); errno = save_errno; @@ -303,7 +316,7 @@ 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); +uschar * key_copy = store_get(klen, is_tainted(key)); memcpy(key_copy, key, klen); @@ -316,7 +329,10 @@ 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); @@ -325,6 +341,34 @@ return yield; } +/* Read a record. If the length is not as expected then delete it, write +an error log line 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 * @@ -347,7 +391,7 @@ 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); +uschar * key_copy = store_get(klen, is_tainted(key)); memcpy(key_copy, key, klen); gptr->time_stamp = time(NULL); @@ -381,7 +425,7 @@ int dbfn_delete(open_db *dbblock, const uschar *key) { int klen = Ustrlen(key) + 1; -uschar * key_copy = store_get(klen); +uschar * key_copy = store_get(klen, is_tainted(key)); DEBUG(D_hints_lookup) debug_printf_indent("dbfn_delete: key=%s\n", key); @@ -416,7 +460,6 @@ dbfn_scan(open_db *dbblock, BOOL start, EXIM_CURSOR **cursor) { 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");