diff options
| author | Ben Hutchings <ben@decadent.org.uk> | 2016-06-22 20:43:35 +0200 |
|---|---|---|
| committer | J. Bruce Fields <bfields@redhat.com> | 2016-06-24 18:11:52 +0200 |
| commit | 999653786df6954a31044528ac3f7a5dadca08f4 (patch) | |
| tree | 1591ca7fc7acbd0128b33701516f85276ad8ff06 /fs/nfsd/nfs4acl.c | |
| parent | posix_acl: Add set_posix_acl (diff) | |
| download | linux-999653786df6954a31044528ac3f7a5dadca08f4.tar.xz linux-999653786df6954a31044528ac3f7a5dadca08f4.zip | |
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>
Diffstat (limited to 'fs/nfsd/nfs4acl.c')
| -rw-r--r-- | fs/nfsd/nfs4acl.c | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/fs/nfsd/nfs4acl.c b/fs/nfsd/nfs4acl.c index 6adabd6049b7..71292a0d6f09 100644 --- a/fs/nfsd/nfs4acl.c +++ b/fs/nfsd/nfs4acl.c @@ -770,9 +770,6 @@ nfsd4_set_nfs4_acl(struct svc_rqst *rqstp, struct svc_fh *fhp, dentry = fhp->fh_dentry; inode = d_inode(dentry); - if (!inode->i_op->set_acl || !IS_POSIXACL(inode)) - return nfserr_attrnotsupp; - if (S_ISDIR(inode->i_mode)) flags = NFS4_ACL_DIR; @@ -782,16 +779,19 @@ nfsd4_set_nfs4_acl(struct svc_rqst *rqstp, struct svc_fh *fhp, if (host_error < 0) goto out_nfserr; - host_error = inode->i_op->set_acl(inode, pacl, ACL_TYPE_ACCESS); + fh_lock(fhp); + + host_error = set_posix_acl(inode, ACL_TYPE_ACCESS, pacl); if (host_error < 0) - goto out_release; + goto out_drop_lock; if (S_ISDIR(inode->i_mode)) { - host_error = inode->i_op->set_acl(inode, dpacl, - ACL_TYPE_DEFAULT); + host_error = set_posix_acl(inode, ACL_TYPE_DEFAULT, dpacl); } -out_release: +out_drop_lock: + fh_unlock(fhp); + posix_acl_release(pacl); posix_acl_release(dpacl); out_nfserr: |