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| author | Corinna Vinschen <corinna@vinschen.de> | 2025-03-30 21:56:33 +0200 |
|---|---|---|
| committer | Corinna Vinschen <corinna@vinschen.de> | 2025-03-30 21:59:57 +0200 |
| commit | 98112b9f6f90dbce1ded637dd533ff0f5a1dffa9 (patch) | |
| tree | 606f895699f8b15c023512970736fa6b094481d9 | |
| parent | aa481e001636389c28458e18250e42a24bfcb272 (diff) | |
| download | newlib-98112b9f6f90dbce1ded637dd533ff0f5a1dffa9.zip newlib-98112b9f6f90dbce1ded637dd533ff0f5a1dffa9.tar.gz newlib-98112b9f6f90dbce1ded637dd533ff0f5a1dffa9.tar.bz2 | |
Cygwin: ACLs: don't allow special accounts as USER entry
While accounts from the BUILTIN, NT AUTHORITY, and NT SERVICE domains
can be owner of a file, they are always treated as group entries if they
show up as additional entrys in a Windows ACL. Consequentially, it
shouldn't be possible to add or remove them as USER entry, for instance,
via setfacl.
Add a check to disallow BUILTIN, NT AUTHORITY, and NT SERVICE accounts
as USER entries in a POSIX ACL.
Fixes: bc444e5aa4ca ("Reapply POSIX ACL changes.")
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
| -rw-r--r-- | winsup/cygwin/release/3.6.1 | 3 | ||||
| -rw-r--r-- | winsup/cygwin/sec/acl.cc | 16 |
2 files changed, 18 insertions, 1 deletions
diff --git a/winsup/cygwin/release/3.6.1 b/winsup/cygwin/release/3.6.1 index c1dbbfb..7a6afe6 100644 --- a/winsup/cygwin/release/3.6.1 +++ b/winsup/cygwin/release/3.6.1 @@ -20,3 +20,6 @@ Fixes: Addresses: https://cygwin.com/pipermail/cygwin/2025-March/257783.html - Fix reference counting when dlopen/dlclose a DLL with RTLD_NODELETE. + +- Disallow accounts from the BUILTIN, NT AUTHORITY, NT SERVICE domains + as USER entry in a POSIX ACL. Only allow USER_OBJ, GROUP_OBJ and GROUP. diff --git a/winsup/cygwin/sec/acl.cc b/winsup/cygwin/sec/acl.cc index 5d27a91..129fe9a 100644 --- a/winsup/cygwin/sec/acl.cc +++ b/winsup/cygwin/sec/acl.cc @@ -256,7 +256,21 @@ set_posix_access (mode_t attr, uid_t uid, gid_t gid, } } if (!aclsid[idx]) - aclsid[idx] = sidfromuid (aclbufp[idx].a_id, &cldap); + { + struct passwd *pw = internal_getpwuid (aclbufp[idx].a_id, &cldap); + if (pw) + { + /* Don't allow to pass special accounts as USER, only as + USER_OBJ, GROUP_OBJ, or GROUP */ +#define BUILTIN "U-BUILTIN\\" +#define NT_AUTH "U-NT AUTHORITY\\" +#define NT_SVC "U-NT SERVICE\\" + if (strncmp (pw->pw_gecos, BUILTIN, strlen (BUILTIN)) != 0 + && strncmp (pw->pw_gecos, NT_AUTH, strlen (NT_AUTH)) != 0 + && strncmp (pw->pw_gecos, NT_SVC, strlen (NT_SVC)) != 0) + aclsid[idx] = (PSID) ((pg_pwd *) pw)->sid; + } + } break; case GROUP_OBJ: aclsid[idx] = group; |