From 4e0621a07ea58a0dc15859be3b743bdeb194a51b Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Wed, 11 Sep 2013 14:24:45 -0700 Subject: [PATCH] exec: don't retry if request_module() fails A separate one-liner for better documentation. It doesn't make sense to retry if request_module() fails to exec /sbin/modprobe, add the additional "request_module() < 0" check. However, this logic still doesn't look exactly right: 1. It would be better to check "request_module() != 0", the user space modprobe process should report the correct exit code. But I didn't dare to add the user-visible change. 2. The whole ENOEXEC logic looks suboptimal. Suppose that we try to exec a "#!path-to-unsupported-binary" script. In this case request_module() + "retry" will be done twice: first by the "depth == 1" code, and then again by the "depth == 0" caller which doesn't make sense. 3. And note that in the case above bprm->buf was already changed by load_script()->prepare_binprm(), so this looks even more ugly. Signed-off-by: Oleg Nesterov Acked-by: Kees Cook Cc: Al Viro Cc: Evgeniy Polyakov Cc: Zach Levis Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/exec.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/exec.c b/fs/exec.c index ba357e6..635b586 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1418,7 +1418,8 @@ int search_binary_handler(struct linux_binprm *bprm) if (printable(bprm->buf[0]) && printable(bprm->buf[1]) && printable(bprm->buf[2]) && printable(bprm->buf[3])) return retval; - request_module("binfmt-%04x", *(ushort *)(bprm->buf + 2)); + if (request_module("binfmt-%04x", *(ushort *)(bprm->buf + 2)) < 0) + return retval; need_retry = false; goto retry; } -- 2.7.4