exec: use -ELOOP for max recursion depth

To avoid an explosion of request_module calls on a chain of abusive
scripts, fail maximum recursion with -ELOOP instead of -ENOEXEC. As soon
as maximum recursion depth is hit, the error will fail all the way back
up the chain, aborting immediately.

This also has the side-effect of stopping the user's shell from attempting
to reexecute the top-level file as a shell script. As seen in the
dash source:

        if (cmd != path_bshell && errno == ENOEXEC) {
                *argv-- = cmd;
                *argv = cmd = path_bshell;
                goto repeat;
        }

The above logic was designed for running scripts automatically that lacked
the "#!" header, not to re-try failed recursion. On a legitimate -ENOEXEC,
things continue to behave as the shell expects.

Additionally, when tracking recursion, the binfmt handlers should not be
involved. The recursion being tracked is the depth of calls through
search_binary_handler(), so that function should be exclusively responsible
for tracking the depth.

Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: halfdog <me@halfdog.net>
Cc: P J P <ppandit@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

path: root/curvetun/Makefile

curvetun-libs =	-l${CONFIG_NACL_LIB} \
		-lpthread

curvetun-objs =	xmalloc.o \
		epoll2.o \
		str.o \
		dev.o \
		stun.o \
		sock.o \
		sig.o \
		link.o \
		patricia.o \
		corking.o \
		trie.o \
		taia.o \
		hash.o \
		rnd.o \
		curve.o \
		curve_test.o \
		cookie.o \
		keypair.o \
		ioexact.o \
		ioops.o \
		cpusched.o \
		die.o \
		sysctl.o \
		curvetun_mgmt_servers.o \
		curvetun_mgmt_users.o \
		curvetun_server.o \
		curvetun_client.o \
		curvetun.o

curvetun-eflags = -I ${CONFIG_NACL_INC_DIR}

curvetun-confs =