Commit 1f2edbe3 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFS: Don't ignore suid/sgid bit changes after a successful write 



If we suspect that the server may have cleared the suid/sgid bit,
then mark the inode for revalidation.

Reported-by: default avatarKinglong Mee <kinglongmee@gmail.com>
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
parent 43b6535e

fs/nfs/write.c

+33 −2
Original line number Diff line number Diff line
@@ -1353,6 +1353,30 @@ static const struct rpc_call_ops nfs_write_common_ops = { 
	.rpc_release = nfs_writeback_release_common,

};



/*

 * Special version of should_remove_suid() that ignores capabilities.

 */

static int nfs_should_remove_suid(const struct inode *inode)

{

	umode_t mode = inode->i_mode;

	int kill = 0;



	/* suid always must be killed */

	if (unlikely(mode & S_ISUID))

		kill = ATTR_KILL_SUID;



	/*

	 * sgid without any exec bits is just a mandatory locking mark; leave

	 * it alone.  If some exec bits are set, it's a real sgid; kill it.

	 */

	if (unlikely((mode & S_ISGID) && (mode & S_IXGRP)))

		kill |= ATTR_KILL_SGID;



	if (unlikely(kill && S_ISREG(mode)))

		return kill;



	return 0;

}



/*

 * This function is called when the WRITE call is complete.
@@ -1401,9 +1425,16 @@ void nfs_writeback_done(struct rpc_task *task, struct nfs_write_data *data) 
		}

	}

#endif

	if (task->tk_status < 0)

	if (task->tk_status < 0) {

		nfs_set_pgio_error(data->header, task->tk_status, argp->offset);

	else if (resp->count < argp->count) {

		return;

	}



	/* Deal with the suid/sgid bit corner case */

	if (nfs_should_remove_suid(inode))

		nfs_mark_for_revalidate(inode);



	if (resp->count < argp->count) {

		static unsigned long    complain;



		/* This a short write! */