From: Kees Cook Subject: module: report -EFAULT on bytes remaining Date: Wed, 12 Sep 2012 08:06:16 -0700 Caught by smatch: kernel/module.c:2450 copy_module_from_user() warn: maybe return -EFAULT instead of the bytes remaining? Clean up the copy_from_user() call to not report a positive value. With this patch, init_module() will report errors from copy_from_user (before it would always only report -EFAULT when err != 0). Reported-by: Fengguang Wu Signed-off-by: Kees Cook Signed-off-by: Rusty Russell (simplified) --- kernel/module.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/module.c b/kernel/module.c --- a/kernel/module.c +++ b/kernel/module.c @@ -2415,9 +2415,10 @@ int copy_module_from_user(const void __u if (!info->hdr) return -ENOMEM; - err = copy_from_user(info->hdr, umod, info->len); - if (err) + if (copy_from_user(info->hdr, umod, info->len)) { + err = -EFAULT; goto free_hdr; + } err = check_info(info); if (err)