[PATCH 4.4 138/192] [PATCH 4.4 08/16] cred: Reject inodes with invalid ids in set_create_file_as()

From: Greg Kroah-Hartman
Date: Mon Sep 12 2016 - 13:12:36 EST


4.4-stable review patch. If anyone has any objections, please let me know.

------------------


From: Seth Forshee <seth.forshee@xxxxxxxxxxxxx>

[ 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@xxxxxxxxxxxxx>
Acked-by: Serge Hallyn <serge.hallyn@xxxxxxxxxxxxx>
Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/cred.c | 2 ++
1 file changed, 2 insertions(+)

--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -689,6 +689,8 @@ EXPORT_SYMBOL(set_security_override_from
*/
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);