--- name: "nbdb_reindexd" section: "8" platform: "linux" package: "postfix" version: "3.11.7-1" release: "Arch Linux 2026-11-01" platforms: ["linux"] url: "https://new.carta.tech/nbdb_reindexd" --- # nbdb\_reindexd(8) Postfix non-Berkeley-DB migration ## NAME nbdb\_reindexd - Postfix non-Berkeley-DB migration ## SYNOPSIS ``` nbdb_reindexd [generic Postfix daemon options] ``` ## DESCRIPTION *NOTE: This service should be enabled only temporarily to* *generate most of the non-Berkeley-DB indexed files that Postfix* *needs. Leaving this service enabled may expose the system to* *privilege-escalation attacks.* The [nbdb\_reindexd(8)](/nbdb_reindexd/8.md) server handles requests to generate a non-Berkeley-DB indexed database file for an existing Berkeley DB database (example: "hash:/path/to/file" or "btree:/path/to/file"). It implements the service by running the [postmap(1)](/postmap/1.md) or [postalias(1)](/postalias/1.md) command with appropriate privileges. The service reports a success status when the non-Berkeley-DB indexed file already exists. This can happen when multiple clients make the same request. When one request is completed successfully, the service also reports success for the other requests. This service enforces the following safety policy: - • The legacy Berkeley DB indexed file must exist (file name ends in ".db"). The [nbdb\_reindexd(8)](/nbdb_reindexd/8.md) service will use the owner"s (uid, gid) of this file, when it runs [postmap(1)](/postmap/1.md) or [postalias(1)](/postalias/1.md). It also uses the (uid,gid) for a number of safety checks as described next. - • The non-indexed source file must exist (file name without ".db" suffix). This file is needed as input for [postmap(1)](/postmap/1.md) or [postalias(1)](/postalias/1.md). The file must be owned by "root" or by the above uid, and must not allow "group" or "other" write access. - • The parent directory must be owned by "root" or by the above uid, and it must not allow "group" or "other" write access. - • Additionally, the "non\_bdb\_migration\_allow\_root\_prefixes" parameter limits the source file directory prefixes that are allowed when this service needs to run [postmap(1)](/postmap/1.md) or [postalias(1)](/postalias/1.md) with "root" privileges. - • A similar parameter, "non\_bdb\_migration\_allow\_user\_prefixes", limits the source file directory prefixes that are allowed when this service needs to run [postmap(1)](/postmap/1.md) or [postalias(1)](/postalias/1.md) as an unprivileged user. ## SECURITY ``` ``` The [nbdb\_reindexd(8)](/nbdb_reindexd/8.md) server is security sensitive. It accepts requests only from processes that can access sockets under $queue\_directory/private (i.e., processes that run with "root" or "mail\_owner" (usually, postfix) privileges). The threat is therefore a corrupted Postfix daemon process that wants to elevate privileges, by sending requests with crafted pathnames, and racing against the service by quickly swapping files or directories, hoping that Postfix will be tricked to overwrite a sensitive file with attacker-controlled data. When the service runs [postmap(1)](/postmap/1.md) or [postalias(1)](/postalias/1.md) as "root", such racing attacks should not be possible if non\_bdb\_migration\_allow\_root\_prefixes specifies only prefixes that are already trusted. This service could block all requests with crafted pathnames, if given complete information about all lookup tables that are referenced through Postfix configuration files. Unfortunately that information was not available at the time that this program was needed. ## DIAGNOSTICS Problems and transactions are logged to [syslogd(8)](/syslogd/8.md) or [postlogd(8)](/postlogd/8.md). If an attempt to create an index file fails, this service will attempt to delete the incomplete file. ## CONFIGURATION PARAMETERS ``` ``` Changes to main.cf are not picked up automatically, as [nbdb\_reindexd(8)](/nbdb_reindexd/8.md) processes are long-lived. Use the command "postfix reload" after a configuration change. The text below provides only a parameter summary. See [postconf(5)](/postconf/5.md) for more details including examples. ## SERVICE-SPECIFIC CONTROLS ``` ``` - **non\_bdb\_migration\_level (disable)** The non-Berkeley-DB migration service level. - **non\_bdb\_migration\_allow\_root\_prefixes (see 'postconf -d non\_bdb\_migration\_allow\_root\_prefixes' output)** A list of trusted pathname prefixes that must be matched when the non-Berkeley-DB migration service ([**nbdb\_reindexd**(8)](/nbdb_reindexd/8.md)) needs to run [**postmap**(1)](/postmap/1.md) or [**postalias**(1)](/postalias/1.md) commands with "root" privilege. - **non\_bdb\_migration\_allow\_user\_prefixes (see 'postconf -d non\_bdb\_migration\_allow\_user\_prefixes' output)** A list of trusted pathname prefixes that must be matched when the non-Berkeley-DB migration service ([**nbdb\_reindexd**(8)](/nbdb_reindexd/8.md)) needs to run [**postmap**(1)](/postmap/1.md) or [**postalias**(1)](/postalias/1.md) commands with non-root privilege. ## MISCELLANEOUS CONTROLS ``` ``` - **config\_directory (see 'postconf -d' output)** The default location of the Postfix main.cf and master.cf configuration files. - **process\_id (read-only)** The process ID of a Postfix command or daemon process. - **process\_name (read-only)** The process name of a Postfix command or daemon process. - **syslog\_facility (mail)** The syslog facility of Postfix logging. - **syslog\_name (see 'postconf -d' output)** A prefix that is prepended to the process name in syslog records, so that, for example, "smtpd" becomes "prefix/smtpd". - **service\_name (read-only)** The master.cf service name of a Postfix daemon process. ## SEE ALSO ``` postfix-non-bdb(1), migration management postconf(5), configuration parameters postlogd(8), Postfix logging syslogd(8), system logging ``` ## README FILES ``` ``` Use "**postconf readme\_directory**" or "**postconf html\_directory**" to locate this information. ``` NON_BERKELEYDB_README, Non-Berkeley-DB migration guide ``` ## LICENSE ``` ``` The Secure Mailer license must be distributed with this software. ## HISTORY This service was introduced with Postfix version 3.11. ## AUTHOR(S) ``` Wietse Venema porcupine.org ```