From: Eric Biggers Date: Fri, 30 Dec 2016 23:42:32 +0000 (-0600) Subject: net: socket: don't set sk_uid to garbage value in ->setattr() X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=e1a3a60a2ebe991605acb14cd58e39c0545e174e;p=linux-beck.git 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. Fixes: 86741ec25462 ("net: core: Add a UID field to struct sock.") Signed-off-by: Eric Biggers Tested-by: Lorenzo Colitti Acked-by: Lorenzo Colitti Signed-off-by: David S. Miller --- diff --git a/net/socket.c b/net/socket.c index 8487bf136e5c..a8c2307590b8 100644 --- a/net/socket.c +++ b/net/socket.c @@ -537,7 +537,7 @@ 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(d_inode(dentry)); sock->sk->sk_uid = iattr->ia_uid;