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authorTobin C. Harding <me@tobin.cc>2018-06-22 09:15:33 +1000
committerTheodore Ts'o <tytso@mit.edu>2018-07-17 21:32:48 -0400
commit1c4facb846c7f863bc65483394e80acdbacf671b (patch)
tree4c43ef97d6ecf95df31b4be6c08178b3fa204914 /lib
parent753d433b586d1d43c487e3d660f5778c7c8d58ea (diff)
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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) <rostedt@goodmis.org> Suggested-by: Kees Cook <keescook@chromium.org> Signed-off-by: Tobin C. Harding <me@tobin.cc> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'lib')
-rw-r--r--lib/vsprintf.c10
1 files changed, 9 insertions, 1 deletions
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(&not_filled_random_ptr_key);
+ return 0;
+ }
+ ret = add_random_ready_callback(&random_ready);
if (!ret) {
return 0;
} else if (ret == -EALREADY) {