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, 1 insertions, 2 deletions

diff --git a/auth.c b/auth.c
index 687c57b42..aed3c13ac 100644
--- a/auth.c
+++ b/auth.c
@@ -474,8 +474,7 @@ check_key_in_hostfiles(struct passwd *pw, struct sshkey *key, const char *host,
                 user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
                 if (options.strict_modes &&
                     (stat(user_hostfile, &st) == 0) &&
-                    ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
-                    (st.st_mode & 022) != 0)) {
+                    !secure_permissions(&st, pw->pw_uid)) {
                         logit("Authentication refused for %.100s: "
                             "bad owner or modes for %.200s",
                             pw->pw_name, user_hostfile);