From 2cc751545854d7bd7eedf4d7e377bb52e176cd07 Mon Sep 17 00:00:00 2001 From: Stephan Mueller Date: Sat, 22 Oct 2016 15:57:05 +0200 Subject: [PATCH] hwrng: core - zeroize buffers with random data The HWRNG core allocates two buffers during initialization which are used to obtain random data. After that data is processed, it is now zeroized as it is possible that the HWRNG core will not be asked to produce more random data for a long time. This prevents leaving such sensitive data in memory. Signed-off-by: Stephan Mueller Signed-off-by: Herbert Xu --- drivers/char/hw_random/core.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c index d2d2c89..f976641 100644 --- a/drivers/char/hw_random/core.c +++ b/drivers/char/hw_random/core.c @@ -92,6 +92,7 @@ static void add_early_randomness(struct hwrng *rng) mutex_unlock(&reading_mutex); if (bytes_read > 0) add_device_randomness(rng_buffer, bytes_read); + memset(rng_buffer, 0, size); } static inline void cleanup_rng(struct kref *kref) @@ -287,6 +288,7 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf, } } out: + memset(rng_buffer, 0, rng_buffer_size()); return ret ? : err; out_unlock_reading: @@ -425,6 +427,7 @@ static int hwrng_fillfn(void *unused) /* Outside lock, sure, but y'know: randomness. */ add_hwgenerator_randomness((void *)rng_fillbuf, rc, rc * current_quality * 8 >> 10); + memset(rng_fillbuf, 0, rng_buffer_size()); } hwrng_fill = NULL; return 0; -- 2.7.4