nfs/blocklayout: Check max uuids and devices before decoding

Avoid nfs return uuids/devices larger than maximum.

Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

diff --git a/fs/nfs/blocklayout/dev.c b/fs/nfs/blocklayout/dev.c
index 7d9f570e1b5216d9dc16081fd7862de4a5e0c9cb..118252fd1d647bc26892e646646e973c7bd30216 100644 (file)
--- a/fs/nfs/blocklayout/dev.c
+++ b/fs/nfs/blocklayout/dev.c
@@ -65,8 +65,8 @@ nfs4_block_decode_volume(struct xdr_stream *xdr, struct pnfs_block_volume *b)
                if (!p)
                        return -EIO;
                b->simple.nr_sigs = be32_to_cpup(p++);
-               if (!b->simple.nr_sigs) {
-                       dprintk("no signature\n");
+               if (!b->simple.nr_sigs || b->simple.nr_sigs > PNFS_BLOCK_MAX_UUIDS) {
+                       dprintk("Bad signature count: %d\n", b->simple.nr_sigs);
                        return -EIO;
                }
 
@@ -105,7 +105,12 @@ nfs4_block_decode_volume(struct xdr_stream *xdr, struct pnfs_block_volume *b)
                p = xdr_inline_decode(xdr, 4);
                if (!p)
                        return -EIO;
+
                b->concat.volumes_count = be32_to_cpup(p++);
+               if (b->concat.volumes_count > PNFS_BLOCK_MAX_DEVICES) {
+                       dprintk("Too many volumes: %d\n", b->concat.volumes_count);
+                       return -EIO;
+               }
 
                p = xdr_inline_decode(xdr, b->concat.volumes_count * 4);
                if (!p)
@@ -117,8 +122,13 @@ nfs4_block_decode_volume(struct xdr_stream *xdr, struct pnfs_block_volume *b)
                p = xdr_inline_decode(xdr, 8 + 4);
                if (!p)
                        return -EIO;
+
                p = xdr_decode_hyper(p, &b->stripe.chunk_size);
                b->stripe.volumes_count = be32_to_cpup(p++);
+               if (b->stripe.volumes_count > PNFS_BLOCK_MAX_DEVICES) {
+                       dprintk("Too many volumes: %d\n", b->stripe.volumes_count);
+                       return -EIO;
+               }
 
                p = xdr_inline_decode(xdr, b->stripe.volumes_count * 4);
                if (!p)