diff options
Diffstat (limited to 'doc/doc-txt/Exim4.upgrade')
| -rw-r--r-- | doc/doc-txt/Exim4.upgrade | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/doc/doc-txt/Exim4.upgrade b/doc/doc-txt/Exim4.upgrade index 528d94d9c..86d4a4dda 100644 --- a/doc/doc-txt/Exim4.upgrade +++ b/doc/doc-txt/Exim4.upgrade @@ -468,11 +468,12 @@ Generic Router Options . The way that require_files works has been changed. Each item in the list is now separately expanded as the test proceeds. The use of leading ! and + characters is unchanged. However, user and group checking is done differently. - Previously, seteuid() was used, but seteuid() is no longer used in Exim (see - "Security" below). Instead, Exim now scans along the components of the file - path and checks the access for the given uid and gid. It expects "x" access - on directories and "r" on the final file. This means that file access control - lists (on those operating systems that have them) are ignored. + Previously, seteuid() was used, but seteuid() is no longer used (see + "Security" below) for checking the files required by this option. Instead, + Exim now scans along the components of the file path and checks the access + for the given uid and gid. It expects "x" access on directories and "r" on + the final file. This means that file access control lists (on those + operating systems that have them) are ignored. Other Consequences of the Director/Router Merge @@ -1380,8 +1381,11 @@ Security -------- Exim 3 could be run in a variety of ways as far as security was concerned. This -has all been simplified in Exim 4. The security-conscious might like to know -that it no longer makes any use of the seteuid() function. +has all been simplified in Exim 4. Exim dropped the use of seteuid() in +most places. But recent (2020-10/2021-04) vulnerabilities forced us to +re-introduce seteuid() for opening the database files (hint files) as secure as +possible. For future (>= 4.95) versions we work on a solution that +does not need the seteuid call. . A UID and GID are required to be specified when Exim is compiled. They can be now specified by name as well as by number, so the relevant options are now |