Previously, higher 32 bits of exit_signal fields were lost when
copied to the kernel args structure (that uses int as a type for the
respective field). Fail with EINVAL if these are set as it looks like
there's no sane reason to accept them.
* kernel/fork.c (copy_clone_args_from_user): Fail with -EINVAL if
args.exit_signal converted to unsigned int is not equal to the original
value.
Signed-off-by: Eugene Syromiatnikov <e...@redhat.com>
---
kernel/fork.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/kernel/fork.c b/kernel/fork.c
index 2852d0e..fcbc4d5 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -2562,6 +2562,9 @@ noinline static int copy_clone_args_from_user(struct
kernel_clone_args *kargs,
if (copy_from_user(&args, uargs, size))
return -EFAULT;
+ if (unlikely(((unsigned int)args.exit_signal) != args.exit_signal))
+ return -EINVAL;
+
*kargs = (struct kernel_clone_args){
.flags = args.flags,
.pidfd = u64_to_user_ptr(args.pidfd),
--
2.1.4
