classes/sanity: check for suid root command evility

Some users have been found to have an unnamed third-party piece of
software installed which sets chmod, chown and mknod as suid root as
part of its installation process. This interferes with the operation of
pseudo and can result in files really being owned by root within the
build output, and therefore breaks the build, apart from being a
security issue. Check for this and bail out if it is found.

Reported-by: Nicolas Dechesne <nicolas.dechesne@linaro.org>
(From OE-Core master rev: 08d61529f3c7a48ec82e1f8c9c28c7b2e5238934)

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

diff --git a/meta/classes/sanity.bbclass b/meta/classes/sanity.bbclass
index 425d5127ecdb59e5630c60b9f447dcd414222e3c..e3444d1ba542baf8bf01ba76404346ad4ea86f90 100644 (file)
--- a/meta/classes/sanity.bbclass
+++ b/meta/classes/sanity.bbclass
@@ -195,6 +195,17 @@ def check_sanity_tmpdir_change(tmpdir, data):
 
     # Check that TMPDIR isn't on a filesystem with limited filename length (eg. eCryptFS)
     testmsg = check_create_long_filename(tmpdir, "TMPDIR")
+
+    # Some third-party software apparently relies on chmod etc. being suid root (!!)
+    import stat
+    suid_check_bins = "chown chmod mknod".split()
+    for bin_cmd in suid_check_bins:
+        bin_path = bb.utils.which(os.environ["PATH"], bin_cmd)
+        if bin_path:
+            bin_stat = os.stat(bin_path)
+            if bin_stat.st_uid == 0 and bin_stat.st_mode & stat.S_ISUID:
+                testmsg = testmsg + '%s has the setuid bit set. This interferes with pseudo and may cause other issues that break the build process.\n' % bin_path
+
     # Check that we can fetch from various network transports
     errmsg = check_connectivity(data)
     testmsg = testmsg + check_connectivity(data)