From a966dcfe153ab0a3d8d79cd971a079411a489be7 Mon Sep 17 00:00:00 2001 From: Eugene Syromiatnikov Date: Sun, 12 Apr 2020 22:26:58 +0200 Subject: [PATCH] clone3: add build-time CLONE_ARGS_SIZE_VER* validity checks CLONE_ARGS_SIZE_VER* macros are defined explicitly and not via the offsets of the relevant struct clone_args fields, which makes it rather error-prone, so it probably makes sense to add some compile-time checks for them (including the one that breaks on struct clone_args extension as a reminder to add a relevant size macro and a similar check). Function copy_clone_args_from_user seems to be a good place for such checks. Signed-off-by: Eugene Syromiatnikov Acked-by: Christian Brauner Link: https://lore.kernel.org/r/20200412202658.GA31499@asgard.redhat.com Signed-off-by: Christian Brauner --- kernel/fork.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/kernel/fork.c b/kernel/fork.c index 3ab7cf88e455..8c700f881d92 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2605,6 +2605,14 @@ noinline static int copy_clone_args_from_user(struct kernel_clone_args *kargs, struct clone_args args; pid_t *kset_tid = kargs->set_tid; + BUILD_BUG_ON(offsetofend(struct clone_args, tls) != + CLONE_ARGS_SIZE_VER0); + BUILD_BUG_ON(offsetofend(struct clone_args, set_tid_size) != + CLONE_ARGS_SIZE_VER1); + BUILD_BUG_ON(offsetofend(struct clone_args, cgroup) != + CLONE_ARGS_SIZE_VER2); + BUILD_BUG_ON(sizeof(struct clone_args) != CLONE_ARGS_SIZE_VER2); + if (unlikely(usize > PAGE_SIZE)) return -E2BIG; if (unlikely(usize < CLONE_ARGS_SIZE_VER0)) -- 2.11.0