From 30e2b629cc9df4c76f63b56afb35ec9f7cc3f1ce Mon Sep 17 00:00:00 2001
From: John Denker <jsd@av8n.com>
Date: Wed, 16 Oct 2013 16:52:59 -0700
Subject: smarter about calculating /total/ entropy
---
drivers/char/random.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
(limited to 'drivers/char')
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 4a2487c..b423214 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -201,6 +201,15 @@
* amount of stored entropy, measured in bits. This includes entropy
* stored in both the input pool and the blocking pool.
+ * Exported interfaces ---- ioctl
+ * ===============================
+ *** FIXME
+
+ **?? There may be older programs out there that write to
+ /dev/random and then do ioctl(RNDADDTOENTCNT...); this
+ is guaranteed to fail insidiously, since writing
+ to /dev/random does nothing to the input pool.
+
* Ensuring unpredictability at system startup
* ============================================
*
@@ -1497,8 +1506,10 @@ static long random_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
case RNDGETENTCNT:
/* inherently racy, no point locking */
if (put_user(input_pool.entropy_count
+#ifdef OVERCOMPLICATED
+ devrand_pool.entropy_count
- + prng_pool.entropy_count, p))
+#endif
+ , p))
return -EFAULT;
return 0;
case RNDADDTOENTCNT:
@@ -1636,7 +1647,7 @@ static int sum_entropy_count(struct ctl_table *table, int write,
#ifdef OVERCOMPLICATED
+ devrand_pool.entropy_count
#endif
- + prng_pool.entropy_count;
+ ;
return proc_dointvec(table, write, buffer, lenp, ppos);
}
--
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