From: Seth Forshee <seth.forshee@canonical.com>
Date: Tue, 30 Aug 2016 04:35:01 +0000 (-0400)
Subject: cred: Reject inodes with invalid ids in set_create_file_as()
X-Git-Tag: firefly_0821_release~176^2~4^2~31^2~55
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=4666aa74a3797d23a2344033df41b2aa0cfe5023;p=firefly-linux-kernel-4.4.55.git

cred: Reject inodes with invalid ids in set_create_file_as()

[ Upstream commit 5f65e5ca286126a60f62c8421b77c2018a482b8a ]

Using INVALID_[UG]ID for the LSM file creation context doesn't
make sense, so return an error if the inode passed to
set_create_file_as() has an invalid id.

Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/kernel/cred.c b/kernel/cred.c
index 71179a09c1d6..ff8606f77d90 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -689,6 +689,8 @@ EXPORT_SYMBOL(set_security_override_from_ctx);
  */
 int set_create_files_as(struct cred *new, struct inode *inode)
 {
+	if (!uid_valid(inode->i_uid) || !gid_valid(inode->i_gid))
+		return -EINVAL;
 	new->fsuid = inode->i_uid;
 	new->fsgid = inode->i_gid;
 	return security_kernel_create_files_as(new, inode);