[OE-core] [PATCH] sanity: Check for setgid/setuid TMPDIR

[Richard Purdie]

Building in a TMPDIR which has setgid or setuid is a bad idea. We could try and reset
the permissions but since these can also invade into other directories like the cache
or sstate, lets tell the user to fix it instead.

[YOCTO #6519]

Signed-off-by: Richard Purdie <richard.purdie at linuxfoundation.org>

diff --git a/meta/classes/sanity.bbclass b/meta/classes/sanity.bbclass
index ed65814..367b68e 100644
--- a/meta/classes/sanity.bbclass
+++ b/meta/classes/sanity.bbclass
@@ -514,6 +514,7 @@ def check_sanity_version_change(status, d):
         import xml.parsers.expat
     except ImportError:
         status.addresult('Your python is not a full install. Please install the module xml.parsers.expat (python-xml on openSUSE and SUSE Linux).\n')
+    import stat
 
     status.addresult(check_make_version(d))
     status.addresult(check_tar_version(d))
@@ -566,6 +567,11 @@ def check_sanity_version_change(status, d):
     # Check that TMPDIR isn't on a filesystem with limited filename length (eg. eCryptFS)
     tmpdir = d.getVar('TMPDIR', True)
     status.addresult(check_create_long_filename(tmpdir, "TMPDIR"))
+    tmpdirmode = os.stat(tmpdir).st_mode
+    if (tmpdirmode & stat.S_ISGID):
+        status.addresult("TMPDIR is setgid, please don't build in a setgid directory")
+    if (tmpdirmode & stat.S_ISUID):
+        status.addresult("TMPDIR is setuid, please don't build in a setgid directory")
 
     # Some third-party software apparently relies on chmod etc. being suid root (!!)
     import stat