]> git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/commit
nfsd: check permissions when setting ACLs
authorBen Hutchings <ben@decadent.org.uk>
Wed, 22 Jun 2016 18:43:35 +0000 (19:43 +0100)
committerJ. Bruce Fields <bfields@redhat.com>
Fri, 24 Jun 2016 16:11:52 +0000 (12:11 -0400)
commit999653786df6954a31044528ac3f7a5dadca08f4
tree1591ca7fc7acbd0128b33701516f85276ad8ff06
parent485e71e8fb6356c08c7fc6bcce4bf02c9a9a663f
nfsd: check permissions when setting ACLs

Use set_posix_acl, which includes proper permission checks, instead of
calling ->set_acl directly.  Without this anyone may be able to grant
themselves permissions to a file by setting the ACL.

Lock the inode to make the new checks atomic with respect to set_acl.
(Also, nfsd was the only caller of set_acl not locking the inode, so I
suspect this may fix other races.)

This also simplifies the code, and ensures our ACLs are checked by
posix_acl_valid.

The permission checks and the inode locking were lost with commit
4ac7249e, which changed nfsd to use the set_acl inode operation directly
instead of going through xattr handlers.

Reported-by: David Sinquin <david@sinquin.eu>
[agreunba@redhat.com: use set_posix_acl]
Fixes: 4ac7249e
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
fs/nfsd/nfs2acl.c
fs/nfsd/nfs3acl.c
fs/nfsd/nfs4acl.c