net: socket: don't set sk_uid to garbage value in ->setattr()

->setattr() was recently implemented for socket files to sync the socket
inode's uid to the new 'sk_uid' member of struct sock.  It does this by
copying over the ia_uid member of struct iattr.  However, ia_uid is
actually only valid when ATTR_UID is set in ia_valid, indicating that
the uid is being changed, e.g. by chown.  Other metadata operations such
as chmod or utimes leave ia_uid uninitialized.  Therefore, sk_uid could
be set to a "garbage" value from the stack.

Fix this by only copying the uid over when ATTR_UID is set.

[backport of net e1a3a60a2ebe991605acb14cd58e39c0545e174e]

Bug: 16355602
Change-Id: I20e53848e54282b72a388ce12bfa88da5e3e9efe
Fixes: 86741ec25462 ("net: core: Add a UID field to struct sock.")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Tested-by: Lorenzo Colitti <lorenzo@google.com>
Acked-by: Lorenzo Colitti <lorenzo@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Git-commit: 10487d4e83e94f6f5ac0912f8af04ad7dd29f071
Git-repo: https://android.googlesource.com/kernel/common.git
Signed-off-by: Srinivasarao P <spathi@codeaurora.org>

This commit is contained in:

Eric Biggers

2016-12-30 17:42:32 -06:00

committed by

syphyr

parent fb2b282658

commit 198c7fd61a

1 changed files with 1 additions and 1 deletions

									
										2

net/socket.c

										View File
									
				@ -531,7 +531,7 @@ int sockfs_setattr(struct dentry *dentry, struct iattr *iattr)

				{

					int err = simple_setattr(dentry, iattr);

					if (!err) {

					if (!err && (iattr->ia_valid & ATTR_UID)) {

						struct socket *sock = SOCKET_I(dentry->d_inode);

						sock->sk->sk_uid = iattr->ia_uid;

net: socket: don't set sk_uid to garbage value in ->setattr()

2 net/socket.c Unescape Escape View File

2

net/socket.c

View File