diff options
author | Torsten Duwe <duwe@lst.de> | 2014-06-14 23:48:41 -0400 |
---|---|---|
committer | Theodore Ts'o <tytso@mit.edu> | 2014-07-15 04:49:40 -0400 |
commit | 0f734e6e768b4b66737b3d3e13f1769a12ecff86 (patch) | |
tree | 637eb77455b97fa9385a442a25406443a6bceda7 | |
parent | be4000bc4644d027c519b6361f5ae3bbfc52c347 (diff) |
hwrng: add per-device entropy derating
This patch introduces a derating factor to struct hwrng for
the random bits going into the kernel input pool, and a common
default derating for drivers which do not specify one.
Signed-off-by: Torsten Duwe <duwe@suse.de>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Acked-by: H. Peter Anvin <hpa@zytor.com>
-rw-r--r-- | drivers/char/hw_random/core.c | 11 | ||||
-rw-r--r-- | include/linux/hw_random.h | 3 |
2 files changed, 13 insertions, 1 deletions
diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c index 48b3c812b9ec..3aaf97c774f1 100644 --- a/drivers/char/hw_random/core.c +++ b/drivers/char/hw_random/core.c | |||
@@ -56,11 +56,15 @@ static LIST_HEAD(rng_list); | |||
56 | static DEFINE_MUTEX(rng_mutex); | 56 | static DEFINE_MUTEX(rng_mutex); |
57 | static int data_avail; | 57 | static int data_avail; |
58 | static u8 *rng_buffer, *rng_fillbuf; | 58 | static u8 *rng_buffer, *rng_fillbuf; |
59 | static unsigned short current_quality = 700; /* an arbitrary 70% */ | 59 | static unsigned short current_quality; |
60 | static unsigned short default_quality; /* = 0; default to "off" */ | ||
60 | 61 | ||
61 | module_param(current_quality, ushort, 0644); | 62 | module_param(current_quality, ushort, 0644); |
62 | MODULE_PARM_DESC(current_quality, | 63 | MODULE_PARM_DESC(current_quality, |
63 | "current hwrng entropy estimation per mill"); | 64 | "current hwrng entropy estimation per mill"); |
65 | module_param(default_quality, ushort, 0644); | ||
66 | MODULE_PARM_DESC(default_quality, | ||
67 | "default entropy content of hwrng per mill"); | ||
64 | 68 | ||
65 | static void start_khwrngd(void); | 69 | static void start_khwrngd(void); |
66 | 70 | ||
@@ -79,6 +83,11 @@ static inline int hwrng_init(struct hwrng *rng) | |||
79 | return err; | 83 | return err; |
80 | } | 84 | } |
81 | 85 | ||
86 | current_quality = rng->quality ? : default_quality; | ||
87 | current_quality &= 1023; | ||
88 | |||
89 | if (current_quality == 0 && hwrng_fill) | ||
90 | kthread_stop(hwrng_fill); | ||
82 | if (current_quality > 0 && !hwrng_fill) | 91 | if (current_quality > 0 && !hwrng_fill) |
83 | start_khwrngd(); | 92 | start_khwrngd(); |
84 | 93 | ||
diff --git a/include/linux/hw_random.h b/include/linux/hw_random.h index 3f075ff00411..914bb08cd738 100644 --- a/include/linux/hw_random.h +++ b/include/linux/hw_random.h | |||
@@ -29,6 +29,8 @@ | |||
29 | * @read: New API. drivers can fill up to max bytes of data | 29 | * @read: New API. drivers can fill up to max bytes of data |
30 | * into the buffer. The buffer is aligned for any type. | 30 | * into the buffer. The buffer is aligned for any type. |
31 | * @priv: Private data, for use by the RNG driver. | 31 | * @priv: Private data, for use by the RNG driver. |
32 | * @quality: Estimation of true entropy in RNG's bitstream | ||
33 | * (per mill). | ||
32 | */ | 34 | */ |
33 | struct hwrng { | 35 | struct hwrng { |
34 | const char *name; | 36 | const char *name; |
@@ -38,6 +40,7 @@ struct hwrng { | |||
38 | int (*data_read)(struct hwrng *rng, u32 *data); | 40 | int (*data_read)(struct hwrng *rng, u32 *data); |
39 | int (*read)(struct hwrng *rng, void *data, size_t max, bool wait); | 41 | int (*read)(struct hwrng *rng, void *data, size_t max, bool wait); |
40 | unsigned long priv; | 42 | unsigned long priv; |
43 | unsigned short quality; | ||
41 | 44 | ||
42 | /* internal. */ | 45 | /* internal. */ |
43 | struct list_head list; | 46 | struct list_head list; |