As part of the work to perform bounds checking on all memcpy() uses, replace the open-coded a deserialization of bytes out of memory into a trailing flexible array by using a flex_array.h helper to perform the allocation, bounds checking, and copying. Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx> Cc: Juergen Gross <jgross@xxxxxxxx> Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx> Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> --- drivers/xen/xenbus/xenbus_dev_frontend.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) diff --git a/drivers/xen/xenbus/xenbus_dev_frontend.c b/drivers/xen/xenbus/xenbus_dev_frontend.c index 597af455a522..4267aaef33fb 100644 --- a/drivers/xen/xenbus/xenbus_dev_frontend.c +++ b/drivers/xen/xenbus/xenbus_dev_frontend.c @@ -81,8 +81,8 @@ struct xenbus_transaction_holder { struct read_buffer { struct list_head list; unsigned int cons; - unsigned int len; - char msg[]; + DECLARE_FLEX_ARRAY_ELEMENTS_COUNT(unsigned int, len); + DECLARE_FLEX_ARRAY_ELEMENTS(char, msg); }; struct xenbus_file_priv { @@ -188,21 +188,17 @@ static ssize_t xenbus_file_read(struct file *filp, */ static int queue_reply(struct list_head *queue, const void *data, size_t len) { - struct read_buffer *rb; + struct read_buffer *rb = NULL; if (len == 0) return 0; if (len > XENSTORE_PAYLOAD_MAX) return -EINVAL; - rb = kmalloc(sizeof(*rb) + len, GFP_KERNEL); - if (rb == NULL) + if (mem_to_flex_dup(&rb, data, len, GFP_KERNEL)) return -ENOMEM; rb->cons = 0; - rb->len = len; - - memcpy(rb->msg, data, len); list_add_tail(&rb->list, queue); return 0; -- 2.32.0