From 1c4facb846c7f863bc65483394e80acdbacf671b Mon Sep 17 00:00:00 2001 From: "Tobin C. Harding" Date: Fri, 22 Jun 2018 09:15:33 +1000 Subject: vsprintf: Use hw RNG for ptr_key Currently we must wait for enough entropy to become available before hashed pointers can be printed. We can remove this wait by using the hw RNG if available. Use hw RNG to get keying material. Reviewed-by: Steven Rostedt (VMware) Suggested-by: Kees Cook Signed-off-by: Tobin C. Harding Signed-off-by: Theodore Ts'o --- lib/vsprintf.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'lib/vsprintf.c') diff --git a/lib/vsprintf.c b/lib/vsprintf.c index a48aaa79d352..6c1fb395bddf 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -1675,8 +1675,16 @@ static struct random_ready_callback random_ready = { static int __init initialize_ptr_random(void) { - int ret = add_random_ready_callback(&random_ready); + int key_size = sizeof(ptr_key); + int ret; + + /* Use hw RNG if available. */ + if (get_random_bytes_arch(&ptr_key, key_size) == key_size) { + static_branch_disable(¬_filled_random_ptr_key); + return 0; + } + ret = add_random_ready_callback(&random_ready); if (!ret) { return 0; } else if (ret == -EALREADY) { -- cgit v1.2.3