kernel: kexec: copy user-array safely

Currently, there is no overflow-check with memdup_user().

Use the new function memdup_array_user() instead of memdup_user() for
duplicating the user-space array safely.

Suggested-by: David Airlie <airlied@redhat.com>
Signed-off-by: Philipp Stanner <pstanner@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Zack Rusin <zackr@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230920123612.16914-4-pstanner@redhat.com

diff --git a/kernel/kexec.c b/kernel/kexec.c
index 107f355..8f35a5a 100644 (file)
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -247,7 +247,7 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
                ((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH_DEFAULT))
                return -EINVAL;
 
-       ksegments = memdup_user(segments, nr_segments * sizeof(ksegments[0]));
+       ksegments = memdup_array_user(segments, nr_segments, sizeof(ksegments[0]));
        if (IS_ERR(ksegments))
                return PTR_ERR(ksegments);