Patch "hwrng: core - Don't use a stack buffer in add_early_randomness()" has been added to the 4.8-stable tree

This is a note to let you know that I've just added the patch titled

hwrng: core - Don't use a stack buffer in add_early_randomness()

to the 4.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
hwrng-core-don-t-use-a-stack-buffer-in-add_early_randomness.patch
and it can be found in the queue-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Andrew Lutomirski <[email protected]>
Date: Mon, 17 Oct 2016 10:06:27 -0700
Subject: hwrng: core - Don't use a stack buffer in add_early_randomness()

From: Andrew Lutomirski <[email protected]>

commit 6d4952d9d9d4dc2bb9c0255d95a09405a1e958f7 upstream.

hw_random carefully avoids using a stack buffer except in add_early_randomness(). This causes a crash in virtio_rng if CONFIG_VMAP_STACK=y.

---
 drivers/char/hw_random/core.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

@@ -84,14 +84,14 @@ static size_t rng_buffer_size(void)
 
 static void add_early_randomness(struct hwrng *rng)
 {
-	unsigned char bytes[16];
 	int bytes_read;
+	size_t size = min_t(size_t, 16, rng_buffer_size());
 
 	mutex_lock(&reading_mutex);
-	bytes_read = rng_get_data(rng, bytes, sizeof(bytes), 1);
+	bytes_read = rng_get_data(rng, rng_buffer, size, 1);
 	mutex_unlock(&reading_mutex);
 	if (bytes_read > 0)
-		add_device_randomness(bytes, bytes_read);
+		add_device_randomness(rng_buffer, bytes_read);
 }
 
 static inline void cleanup_rng(struct kref *kref)

Patches currently in stable-queue which might be from [email protected] are

queue-4.8/hwrng-core-don-t-use-a-stack-buffer-in-add_early_randomness.patch