lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [day] [month] [year] [list]
Date:   Tue, 10 Aug 2021 18:31:01 -0500
From:   "Gustavo A. R. Silva" <>
To:     Trond Myklebust <>,
        Anna Schumaker <>
        "Gustavo A. R. Silva" <>,
Subject: [PATCH][next] nfs41: pnfs: filelayout: Replace one-element array
 with flexible-array member

There is a regular need in the kernel to provide a way to declare having
a dynamically sized set of trailing elements in a structure. Kernel code
should always use “flexible array members”[1] for these cases. The older
style of one-element or zero-length arrays should no longer be used[2].

Refactor the code a bit according to the use of a flexible-array member
in struct nfs4_file_layout_dsaddr instead of a one-element array, and
use the struct_size() helper.

This helps with the ongoing efforts to globally enable -Warray-bounds
and get us closer to being able to tighten the FORTIFY_SOURCE routines
on memcpy().

This issue was found with the help of Coccinelle and audited and fixed,


Signed-off-by: Gustavo A. R. Silva <>
 fs/nfs/filelayout/filelayout.h    | 2 +-
 fs/nfs/filelayout/filelayoutdev.c | 4 +---
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/fs/nfs/filelayout/filelayout.h b/fs/nfs/filelayout/filelayout.h
index 79323b5dab0c..aed0748fd6ec 100644
--- a/fs/nfs/filelayout/filelayout.h
+++ b/fs/nfs/filelayout/filelayout.h
@@ -51,7 +51,7 @@ struct nfs4_file_layout_dsaddr {
 	u32				stripe_count;
 	u8				*stripe_indices;
 	u32				ds_num;
-	struct nfs4_pnfs_ds		*ds_list[1];
+	struct nfs4_pnfs_ds		*ds_list[];
 struct nfs4_filelayout_segment {
diff --git a/fs/nfs/filelayout/filelayoutdev.c b/fs/nfs/filelayout/filelayoutdev.c
index 86c3f7e69ec4..acf4b88889dc 100644
--- a/fs/nfs/filelayout/filelayoutdev.c
+++ b/fs/nfs/filelayout/filelayoutdev.c
@@ -136,9 +136,7 @@ nfs4_fl_alloc_deviceid_node(struct nfs_server *server, struct pnfs_device *pdev,
 		goto out_err_free_stripe_indices;
-	dsaddr = kzalloc(sizeof(*dsaddr) +
-			(sizeof(struct nfs4_pnfs_ds *) * (num - 1)),
-			gfp_flags);
+	dsaddr = kzalloc(struct_size(dsaddr, ds_list, num), gfp_flags);
 	if (!dsaddr)
 		goto out_err_free_stripe_indices;

Powered by blists - more mailing lists