Allow harmless group-writability

Allow secure files (~/.ssh/config, ~/.ssh/authorized_keys, etc.) to be
group-writable, provided that the group in question contains only the file's
owner.  Rejected upstream for IMO incorrect reasons (e.g. a misunderstanding
about the contents of gr->gr_mem).  Given that per-user groups and umask 002
are the default setup in Debian (for good reasons - this makes operating in
setgid directories with other groups much easier), we need to permit this by
default.

Bug: https://bugzilla.mindrot.org/show_bug.cgi?id=1060
Bug-Debian: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=314347
Last-Update: 2019-10-09

Patch-Name: user-group-modes.patch

1 files changed, 2 insertions, 0 deletions

diff --git a/ssh.1 b/ssh.1
index db5c65bc7..cf991e4ee 100644
--- a/ssh.1
+++ b/ssh.1
@@ -1506,6 +1506,8 @@ The file format and configuration options are described in
 .Xr ssh_config 5 .
 Because of the potential for abuse, this file must have strict permissions:
 read/write for the user, and not writable by others.
+It may be group-writable provided that the group in question contains only
+the user.
 .Pp
 .It Pa ~/.ssh/environment
 Contains additional definitions for environment variables; see