NFSD: Annotate struct pnfs_block_deviceaddr with __counted_by()

Add the __counted_by compiler attribute to the flexible array member
volumes to improve access bounds-checking via CONFIG_UBSAN_BOUNDS and
CONFIG_FORTIFY_SOURCE.

Use struct_size() instead of manually calculating the number of bytes to
allocate for a pnfs_block_deviceaddr with a single volume.

Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Acked-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

diff --git a/fs/nfsd/blocklayout.c b/fs/nfsd/blocklayout.c
index 3c040c81c77d019c88f0694463da10a04487b4ce..08a20e5bcf7fee0ea6ae6bd5a3fd7622c77977ed 100644 (file)
--- a/fs/nfsd/blocklayout.c
+++ b/fs/nfsd/blocklayout.c
@@ -147,8 +147,7 @@ nfsd4_block_get_device_info_simple(struct super_block *sb,
        struct pnfs_block_deviceaddr *dev;
        struct pnfs_block_volume *b;
 
-       dev = kzalloc(sizeof(struct pnfs_block_deviceaddr) +
-                     sizeof(struct pnfs_block_volume), GFP_KERNEL);
+       dev = kzalloc(struct_size(dev, volumes, 1), GFP_KERNEL);
        if (!dev)
                return -ENOMEM;
        gdp->gd_device = dev;
@@ -255,8 +254,7 @@ nfsd4_block_get_device_info_scsi(struct super_block *sb,
        const struct pr_ops *ops;
        int ret;
 
-       dev = kzalloc(sizeof(struct pnfs_block_deviceaddr) +
-                     sizeof(struct pnfs_block_volume), GFP_KERNEL);
+       dev = kzalloc(struct_size(dev, volumes, 1), GFP_KERNEL);
        if (!dev)
                return -ENOMEM;
        gdp->gd_device = dev;

diff --git a/fs/nfsd/blocklayoutxdr.h b/fs/nfsd/blocklayoutxdr.h
index b0361e8aa9a7e7e0d97fe5edb588acea9db1ea17..4e28ac8f11279746dd2f5b5d3ae42c00a2861e72 100644 (file)
--- a/fs/nfsd/blocklayoutxdr.h
+++ b/fs/nfsd/blocklayoutxdr.h
@@ -47,7 +47,7 @@ struct pnfs_block_volume {
 
 struct pnfs_block_deviceaddr {
        u32                             nr_volumes;
-       struct pnfs_block_volume        volumes[];
+       struct pnfs_block_volume        volumes[] __counted_by(nr_volumes);
 };
 
 __be32 nfsd4_block_encode_getdeviceinfo(struct xdr_stream *xdr,