Commit 99965378 authored by Ben Hutchings's avatar Ben Hutchings Committed by J. Bruce Fields

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: default avatarDavid 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: default avatarJ. Bruce Fields <bfields@redhat.com>
parent 485e71e8
......@@ -104,22 +104,21 @@ static __be32 nfsacld_proc_setacl(struct svc_rqst * rqstp,
goto out;
inode = d_inode(fh->fh_dentry);
if (!IS_POSIXACL(inode) || !inode->i_op->set_acl) {
error = -EOPNOTSUPP;
goto out_errno;
}
error = fh_want_write(fh);
if (error)
goto out_errno;
error = inode->i_op->set_acl(inode, argp->acl_access, ACL_TYPE_ACCESS);
fh_lock(fh);
error = set_posix_acl(inode, ACL_TYPE_ACCESS, argp->acl_access);
if (error)
goto out_drop_write;
error = inode->i_op->set_acl(inode, argp->acl_default,
ACL_TYPE_DEFAULT);
goto out_drop_lock;
error = set_posix_acl(inode, ACL_TYPE_DEFAULT, argp->acl_default);
if (error)
goto out_drop_write;
goto out_drop_lock;
fh_unlock(fh);
fh_drop_write(fh);
......@@ -131,7 +130,8 @@ out:
posix_acl_release(argp->acl_access);
posix_acl_release(argp->acl_default);
return nfserr;
out_drop_write:
out_drop_lock:
fh_unlock(fh);
fh_drop_write(fh);
out_errno:
nfserr = nfserrno(error);
......
......@@ -95,22 +95,20 @@ static __be32 nfsd3_proc_setacl(struct svc_rqst * rqstp,
goto out;
inode = d_inode(fh->fh_dentry);
if (!IS_POSIXACL(inode) || !inode->i_op->set_acl) {
error = -EOPNOTSUPP;
goto out_errno;
}
error = fh_want_write(fh);
if (error)
goto out_errno;
error = inode->i_op->set_acl(inode, argp->acl_access, ACL_TYPE_ACCESS);
fh_lock(fh);
error = set_posix_acl(inode, ACL_TYPE_ACCESS, argp->acl_access);
if (error)
goto out_drop_write;
error = inode->i_op->set_acl(inode, argp->acl_default,
ACL_TYPE_DEFAULT);
goto out_drop_lock;
error = set_posix_acl(inode, ACL_TYPE_DEFAULT, argp->acl_default);
out_drop_write:
out_drop_lock:
fh_unlock(fh);
fh_drop_write(fh);
out_errno:
nfserr = nfserrno(error);
......
......@@ -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:
......
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