Messages in this thread Patch in this message | | | Date | Sun, 12 Apr 2020 22:25:33 +0200 | From | Eugene Syromiatnikov <> | Subject | [PATCH] clone3: fix cgroup argument sanity check |
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Checking that cgroup field value of struct clone_args is less than 0 is useless, as it is defined as unsigned 64-bit integer. Moreover, it doesn't catch the situations where its higher bits are lost during the assignment to the cgroup field of the cgroup field of the internal struct kernel_clone_args (where it is declared as signed 32-bit integer), so it is still possible to pass garbage there. A check against INT_MAX solves both these issues.
Fixes: ef2c41cf38a7559b ("clone3: allow spawning processes into cgroups") Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com> --- kernel/fork.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/fork.c b/kernel/fork.c index 4385f3d..b4f7775 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2631,7 +2631,7 @@ noinline static int copy_clone_args_from_user(struct kernel_clone_args *kargs, !valid_signal(args.exit_signal))) return -EINVAL; - if ((args.flags & CLONE_INTO_CGROUP) && args.cgroup < 0) + if ((args.flags & CLONE_INTO_CGROUP) && args.cgroup > INT_MAX) return -EINVAL; *kargs = (struct kernel_clone_args){ -- 2.1.4
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