Merge tag 'nfsd-5.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux

Pull more nfsd fixes from Chuck Lever:
 "Ensure that NFS clients cannot send file size or offset values that
  can cause the NFS server to crash or to return incorrect or surprising
  results.

  In particular, fix how the NFS server handles values larger than
  OFFSET_MAX"

* tag 'nfsd-5.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux:
  NFSD: Deprecate NFS_OFFSET_MAX
  NFSD: Fix offset type in I/O trace points
  NFSD: COMMIT operations must not return NFS?ERR_INVAL
  NFSD: Clamp WRITE offsets
  NFSD: Fix NFSv3 SETATTR/CREATE's handling of large file sizes
  NFSD: Fix ia_size underflow
  NFSD: Fix the behavior of READ near OFFSET_MAX

1 files changed, 40 insertions, 17 deletions

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 99c2b9dfbb10..91600e71be19 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -435,6 +435,10 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
 			.ia_size	= iap->ia_size,
 		};
 
+		host_err = -EFBIG;
+		if (iap->ia_size < 0)
+			goto out_unlock;
+
 		host_err = notify_change(&init_user_ns, dentry, &size_attr, NULL);
 		if (host_err)
 			goto out_unlock;
@@ -1110,42 +1114,61 @@ out:
 }
 
 #ifdef CONFIG_NFSD_V3
-/*
- * Commit all pending writes to stable storage.
+/**
+ * nfsd_commit - Commit pending writes to stable storage
+ * @rqstp: RPC request being processed
+ * @fhp: NFS filehandle
+ * @offset: raw offset from beginning of file
+ * @count: raw count of bytes to sync
+ * @verf: filled in with the server's current write verifier
  *
- * Note: we only guarantee that data that lies within the range specified
- * by the 'offset' and 'count' parameters will be synced.
+ * Note: we guarantee that data that lies within the range specified
+ * by the 'offset' and 'count' parameters will be synced. The server
+ * is permitted to sync data that lies outside this range at the
+ * same time.
  *
  * Unfortunately we cannot lock the file to make sure we return full WCC
  * data to the client, as locking happens lower down in the filesystem.
+ *
+ * Return values:
+ *   An nfsstat value in network byte order.
  */
 __be32
-nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp,
-               loff_t offset, unsigned long count, __be32 *verf)
+nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp, u64 offset,
+	    u32 count, __be32 *verf)
 {
+	u64			maxbytes;
+	loff_t			start, end;
 	struct nfsd_net		*nn;
 	struct nfsd_file	*nf;
-	loff_t			end = LLONG_MAX;
-	__be32			err = nfserr_inval;
-
-	if (offset < 0)
-		goto out;
-	if (count != 0) {
-		end = offset + (loff_t)count - 1;
-		if (end < offset)
-			goto out;
-	}
+	__be32			err;
 
 	err = nfsd_file_acquire(rqstp, fhp,
 			NFSD_MAY_WRITE|NFSD_MAY_NOT_BREAK_LEASE, &nf);
 	if (err)
 		goto out;
+
+	/*
+	 * Convert the client-provided (offset, count) range to a
+	 * (start, end) range. If the client-provided range falls
+	 * outside the maximum file size of the underlying FS,
+	 * clamp the sync range appropriately.
+	 */
+	start = 0;
+	end = LLONG_MAX;
+	maxbytes = (u64)fhp->fh_dentry->d_sb->s_maxbytes;
+	if (offset < maxbytes) {
+		start = offset;
+		if (count && (offset + count - 1 < maxbytes))
+			end = offset + count - 1;
+	}
+
 	nn = net_generic(nf->nf_net, nfsd_net_id);
 	if (EX_ISSYNC(fhp->fh_export)) {
 		errseq_t since = READ_ONCE(nf->nf_file->f_wb_err);
 		int err2;
 
-		err2 = vfs_fsync_range(nf->nf_file, offset, end, 0);
+		err2 = vfs_fsync_range(nf->nf_file, start, end, 0);
 		switch (err2) {
 		case 0:
 			nfsd_copy_write_verifier(verf, nn);