tmpfs: clear S_ISGID when setting posix ACLs
commit 497de07d89c1410d76a15bec2bb41f24a2a89f31 upstream.
This change was missed the tmpfs modification in In CVE-2016-7097
commit 073931017b49 ("posix_acl: Clear SGID bit when setting
file permissions")
It can test by xfstest generic/375, which failed to clear
setgid bit in the following test case on tmpfs:
touch $testfile
chown 100:100 $testfile
chmod 2755 $testfile
_runas -u 100 -g 101 -- setfacl -m u::rwx,g::rwx,o::rwx $testfile
Signed-off-by: Gu Zheng <guzheng1@huawei.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Brad Spengler <spender@grsecurity.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 5955220..c9d48dc 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -922,11 +922,10 @@
int error;
if (type == ACL_TYPE_ACCESS) {
- error = posix_acl_equiv_mode(acl, &inode->i_mode);
- if (error < 0)
- return 0;
- if (error == 0)
- acl = NULL;
+ error = posix_acl_update_mode(inode,
+ &inode->i_mode, &acl);
+ if (error)
+ return error;
}
inode->i_ctime = current_time(inode);