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, 4 deletions

diff --git a/auth-rhosts.c b/auth-rhosts.c
index 7a10210b6..587f53721 100644
--- a/auth-rhosts.c
+++ b/auth-rhosts.c
@@ -260,8 +260,7 @@ auth_rhosts2(struct passwd *pw, const char *client_user, const char *hostname,
                 return 0;
         }
         if (options.strict_modes &&
-            ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
-            (st.st_mode & 022) != 0)) {
+            !secure_permissions(&st, pw->pw_uid)) {
                 logit("Rhosts authentication refused for %.100s: "
                     "bad ownership or modes for home directory.", pw->pw_name);
                 auth_debug_add("Rhosts authentication refused for %.100s: "
@@ -287,8 +286,7 @@ auth_rhosts2(struct passwd *pw, const char *client_user, const char *hostname,
                  * allowing access to their account by anyone.
                  */
                 if (options.strict_modes &&
-                    ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
-                    (st.st_mode & 022) != 0)) {
+                    !secure_permissions(&st, pw->pw_uid)) {
                         logit("Rhosts authentication refused for %.100s: bad modes for %.200s",
                             pw->pw_name, buf);
                         auth_debug_add("Bad file modes for %.200s", buf);