On Wed, 2024-12-18 at 00:13 +0800, Gax-c wrote:

From: Zichen Xie zichenxie0106@gmail.com

name is char[64] where the size of clnt->cl_program->name remains unknown. Invoking strcat() directly will also lead to potential buffer overflow. Change them to strscpy() and strncat() to fix potential issues.

What makes you think that clnt->cl_program->name is unknown?

All calls to nfs_sysfs_link_rpc_client() use well known RPC clients for which the cl_program is pointing to one of nlm_program, nfs_program or nfsacl_program. So we know very well the sizes of clnt->cl_program-

name.

Fixes: e13b549319a6 ("NFS: Add sysfs links to sunrpc clients for nfs_clients") Signed-off-by: Zichen Xie zichenxie0106@gmail.com Cc: stable@vger.kernel.org

---

fs/nfs/sysfs.c | 6 +++---  1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/nfs/sysfs.c b/fs/nfs/sysfs.c index bf378ecd5d9f..7b59a40d40c0 100644 --- a/fs/nfs/sysfs.c +++ b/fs/nfs/sysfs.c @@ -280,9 +280,9 @@ void nfs_sysfs_link_rpc_client(struct nfs_server *server,   char name[RPC_CLIENT_NAME_SIZE];   int ret;

• strcpy(name, clnt->cl_program->name);
• strcat(name, uniq ? uniq : "");
• strcat(name, "_client");

• strscpy(name, clnt->cl_program->name, sizeof(name));
• strncat(name, uniq ? uniq : "", sizeof(name) - strlen(name)

• 1);

• strncat(name, "_client", sizeof(name) - strlen(name) - 1);

ret = sysfs_create_link_nowarn(&server->kobj,   &clnt->cl_sysfs-

...

kobject, name);