https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=a5bcfe616c7e8f78f464bf045595d8213244876a
commit a5bcfe616c7e8f78f464bf045595d8213244876a Author: Corinna Vinschen <[email protected]> AuthorDate: Fri Dec 2 16:49:47 2022 +0100 Commit: Corinna Vinschen <[email protected]> CommitDate: Fri Dec 2 16:49:47 2022 +0100 Cygwin: uinfo: don't special case current user fetch_account_from_windows shortcuts the current user in that it takes the user's domain SID and just adds the matching RID from the token's primary group to create a group SID. How wrong this is can be very simply reproduced: Assuming you run a native process, like cmd, with primary group set to the Administrators builtin group. Run Cygwin's id(1) as child process. id(1) will print a non-existent group as primary group and also add it to the group list. This can only be avoided by not special casing the current user and thus not creating a group SID from partial information. Fixes: 6cc7c925ce86 ("(pwdgrp::fetch_account_from_windows): Default primary group for the current user to primary group from user token.") Signed-off-by: Corinna Vinschen <[email protected]> Diff: --- winsup/cygwin/uinfo.cc | 24 ++++++------------------ 1 file changed, 6 insertions(+), 18 deletions(-) diff --git a/winsup/cygwin/uinfo.cc b/winsup/cygwin/uinfo.cc index db475d710eb2..6df8c7bbbbe9 100644 --- a/winsup/cygwin/uinfo.cc +++ b/winsup/cygwin/uinfo.cc @@ -1855,7 +1855,6 @@ pwdgrp::fetch_account_from_windows (fetch_user_arg_t &arg, cyg_ldap *pldap) gid_t gid = ILLEGAL_GID; bool is_domain_account = true; PCWSTR domain = NULL; - bool is_current_user = false; char *shell = NULL; char *home = NULL; char *gecos = NULL; @@ -2314,18 +2313,9 @@ pwdgrp::fetch_account_from_windows (fetch_user_arg_t &arg, cyg_ldap *pldap) uid = posix_offset + sid_sub_auth_rid (sid); if (!is_group () && acc_type == SidTypeUser) { - /* Default primary group. If the sid is the current user, fetch - the default group from the current user token, otherwise make - the educated guess that the user is in group "Domain Users" - or "None". */ - if (sid == cygheap->user.sid ()) - { - is_current_user = true; - gid = posix_offset - + sid_sub_auth_rid (cygheap->user.groups.pgsid); - } - else - gid = posix_offset + DOMAIN_GROUP_RID_USERS; + /* Default primary group. Make the educated guess that the user + is in group "Domain Users" or "None". */ + gid = posix_offset + DOMAIN_GROUP_RID_USERS; } if (is_domain_account) @@ -2336,11 +2326,9 @@ pwdgrp::fetch_account_from_windows (fetch_user_arg_t &arg, cyg_ldap *pldap) /* On AD machines, use LDAP to fetch domain account infos. */ if (cygheap->dom.primary_dns_name ()) { - /* For the current user we got correctly cased username and - the primary group via process token. For any other user - we fetch it from AD and overwrite it. */ - if (!is_current_user - && cldap->fetch_ad_account (sid, false, domain)) + /* Fetch primary group from AD and overwrite the one we + just guessed above. */ + if (cldap->fetch_ad_account (sid, false, domain)) { if ((val = cldap->get_account_name ())) wcscpy (name, val);
