DivestOS/Patches/LineageOS-21.0/android_bionic/0002-Graphene_Bionic_Hardening-3.patch

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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Daniel Micay <danielmicay@gmail.com>
Date: Mon, 4 Mar 2019 04:26:04 -0500
Subject: [PATCH] use blocking getrandom and avoid urandom fallback
Signed-off-by: anupritaisno1 <www.anuprita804@gmail.com>
---
libc/bionic/getentropy.cpp | 28 +++-------------------------
1 file changed, 3 insertions(+), 25 deletions(-)
diff --git a/libc/bionic/getentropy.cpp b/libc/bionic/getentropy.cpp
index 9c93e713b..c9438ad2b 100644
--- a/libc/bionic/getentropy.cpp
+++ b/libc/bionic/getentropy.cpp
@@ -33,22 +33,6 @@
#include "private/ScopedFd.h"
-static int getentropy_urandom(void* buffer, size_t buffer_size, int saved_errno) {
- ScopedFd fd(TEMP_FAILURE_RETRY(open("/dev/urandom", O_RDONLY | O_NOFOLLOW | O_CLOEXEC, 0)));
- if (fd.get() == -1) return -1;
-
- size_t collected = 0;
- while (collected < buffer_size) {
- ssize_t count = TEMP_FAILURE_RETRY(read(fd.get(), static_cast<char*>(buffer) + collected,
- buffer_size - collected));
- if (count == -1) return -1;
- collected += count;
- }
-
- errno = saved_errno;
- return 0;
-}
-
int getentropy(void* buffer, size_t buffer_size) {
if (buffer_size > 256) {
errno = EIO;
@@ -59,16 +43,10 @@ int getentropy(void* buffer, size_t buffer_size) {
size_t collected = 0;
while (collected < buffer_size) {
- long count = TEMP_FAILURE_RETRY(getrandom(static_cast<char*>(buffer) + collected,
- buffer_size - collected, GRND_NONBLOCK));
+ long count = TEMP_FAILURE_RETRY(
+ getrandom(static_cast<char*>(buffer) + collected, buffer_size - collected, 0));
if (count == -1) {
- // EAGAIN: there isn't enough entropy right now.
- // ENOSYS/EINVAL: getrandom(2) or GRND_NONBLOCK isn't supported.
- // EFAULT: `buffer` is invalid.
- // Try /dev/urandom regardless because it can't hurt,
- // and we don't need to optimize the EFAULT case.
- // See http://b/33059407 and http://b/67015565.
- return getentropy_urandom(buffer, buffer_size, saved_errno);
+ return -1;
}
collected += count;
}