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: 2013-09-14

Patch-Name: user-group-modes.patch

1 files changed, 3 insertions, 6 deletions

diff --git a/auth.c b/auth.c
index 9a36f1dac..0c45f0954 100644
--- a/auth.c
+++ b/auth.c
@@ -407,8 +407,7 @@ check_key_in_hostfiles(struct passwd *pw, Key *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);
@@ -470,8 +469,7 @@ auth_secure_path(const char *name, struct stat *stp, const char *pw_dir,
                 snprintf(err, errlen, "%s is not a regular file", buf);
                 return -1;
         }
-        if ((!platform_sys_dir_uid(stp->st_uid) && stp->st_uid != uid) ||
-            (stp->st_mode & 022) != 0) {
+        if (!secure_permissions(stp, uid)) {
                 snprintf(err, errlen, "bad ownership or modes for file %s",
                     buf);
                 return -1;
@@ -486,8 +484,7 @@ auth_secure_path(const char *name, struct stat *stp, const char *pw_dir,
                 strlcpy(buf, cp, sizeof(buf));
 
                 if (stat(buf, &st) < 0 ||
-                    (!platform_sys_dir_uid(st.st_uid) && st.st_uid != uid) ||
-                    (st.st_mode & 022) != 0) {
+                    !secure_permissions(&st, uid)) {
                         snprintf(err, errlen,
                             "bad ownership or modes for directory %s", buf);
                         return -1;